To meet the growing needs of flexible and wearable electronics,stretchable energy storage devices—especially supercapacitors(SCs)—have become a key focus in advanced energy storage research.However,achieving both me...To meet the growing needs of flexible and wearable electronics,stretchable energy storage devices—especially supercapacitors(SCs)—have become a key focus in advanced energy storage research.However,achieving both mechanical stretchability and high capacitance in SC still faces great challenges,and the crucial factors lie in creating superior electrode materials that exhibit high electrochemical performance as well as excellent mechanical stretchability.Covalent organic frameworks(COFs)possess considerable potential as electrode materials for SCs by virtue of stable organic frameworks,open channels and designable functional groups.Nevertheless,their applications in flexible SCs are greatly hindered by their rigid characteristics.Here a novel COFs@conductive polymer hydrogels(CPHs)@poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate)(PEDOT:PSS)complexes,which integrate the pseudocapacitance of PDITAPA COF,mechanical stretchability of hydrogels and high conductivity of PEDOT:PSS,has been developed as stretchable electrode of SCs.Physically cross-linked PEDOT nanofibers,with their interlinked and entangled architecture,collectively boost mechanical,electrical,and electrochemical performance.The COFs@CPHs@PEDOT:PSS simultaneously demonstrates outstanding mechanical stretchability,high electrical behaviors,and superior swelling characteristics.The resulting SC exhibits advantages of simple structures,facile assembly processes,high specific capacitance,excellent cycling stability,and arbitrary deformation,which holds great application prospects for wearable electronic products.Owing to its uncomplicated structure,ease of production,high energy storage capacity,robust cycling performance,and adaptability to deformation,this fabricated SC is well-suited for next-generation wearable technologies.展开更多
Graphitic carbon nitride(g-C_(3)N_(4)),known for its green and abundant nature and composed of carbon and nitrogen in a two-dimensional structure,has emerged as a significant area of interest across various discipline...Graphitic carbon nitride(g-C_(3)N_(4)),known for its green and abundant nature and composed of carbon and nitrogen in a two-dimensional structure,has emerged as a significant area of interest across various disciplines,particularly in energy conversion and storage.Its recent demonstrations of high potential in supercapacitor applications mark it as a promising alternative to graphene within the realm of materials science.Numerous favorable features,such as chemical and thermal stability,abundant nitrogen content,eco-friendly attributes,and gentle conditions for synthesis,are shown.This review summarizes recent advancements in the use of g-C_(3)N_(4)and its composites as electrodes for supercapacitors,highlighting the advantages and issues associated with g-C_(3)N_(4)in these applications.This emphasizes situations where the composition of g-C_(3)N_(4)with other materials,such as metal oxides,metal chalcogenides,carbon materials,and conducting polymers,overcomes its limitations,leading to composite materials with improved functionalities.This review discusses the challenges that still need to be addressed and the possible future roles of g-C_(3)N_(4)in the research of advanced supercapacitor technology,such as battery-hybrid supercapacitors,flexible supercapacitors,and photo-supercapacitors.展开更多
Supercapacitors are gaining popularity due to their high cycling stability,power density,and fast charge and discharge rates.Researchers are ex-ploring electrode materials,electrolytes,and separat-ors for cost-effecti...Supercapacitors are gaining popularity due to their high cycling stability,power density,and fast charge and discharge rates.Researchers are ex-ploring electrode materials,electrolytes,and separat-ors for cost-effective energy storage systems.Ad-vances in materials science have led to the develop-ment of hybrid nanomaterials,such as combining fil-amentous carbon forms with inorganic nanoparticles,to create new charge and energy transfer processes.Notable materials for electrochemical energy-stor-age applications include MXenes,2D transition met-al carbides,and nitrides,carbon black,carbon aerogels,activated carbon,carbon nanotubes,conducting polymers,carbon fibers,and nanofibers,and graphene,because of their thermal,electrical,and mechanical properties.Carbon materials mixed with conducting polymers,ceramics,metal oxides,transition metal oxides,metal hydroxides,transition metal sulfides,trans-ition metal dichalcogenide,metal sulfides,carbides,nitrides,and biomass materials have received widespread attention due to their remarkable performance,eco-friendliness,cost-effectiveness,and renewability.This article explores the development of carbon-based hybrid materials for future supercapacitors,including electric double-layer capacitors,pseudocapacitors,and hy-brid supercapacitors.It investigates the difficulties that influence structural design,manufacturing(electrospinning,hydro-thermal/solvothermal,template-assisted synthesis,electrodeposition,electrospray,3D printing)techniques and the latest car-bon-based hybrid materials research offer practical solutions for producing high-performance,next-generation supercapacitors.展开更多
With the rapid development of flexible wearable electronics,the demand for stretchable energy storage devices has surged.In this work,a novel gradient-layered architecture was design based on single-pore hollow lignin...With the rapid development of flexible wearable electronics,the demand for stretchable energy storage devices has surged.In this work,a novel gradient-layered architecture was design based on single-pore hollow lignin nanospheres(HLNPs)-intercalated two-dimensional transition metal carbide(Ti_(3)C_(2)T_(x) MXene)for fabricating highly stretchable and durable supercapacitors.By depositing and inserting HLNPs in the MXene layers with a bottom-up decreasing gradient,a multilayered porous MXene structure with smooth ion channels was constructed by reducing the overstacking of MXene lamella.Moreover,the micro-chamber architecture of thin-walled lignin nanospheres effectively extended the contact area between lignin and MXene to improve ion and electron accessibility,thus better utilizing the pseudocapacitive property of lignin.All these strategies effectively enhanced the capacitive performance of the electrodes.In addition,HLNPs,which acted as a protective phase for MXene layer,enhanced mechanical properties of the wrinkled stretchable electrodes by releasing stress through slip and deformation during the stretch-release cycling and greatly improved the structural integrity and capacitive stability of the electrodes.Flexible electrodes and symmetric flexible all-solid-state supercapacitors capable of enduring 600%uniaxial tensile strain were developed with high specific capacitances of 1273 mF cm^(−2)(241 F g^(−1))and 514 mF cm^(−2)(95 F g^(−1)),respectively.Moreover,their capacitances were well preserved after 1000 times of 600%stretch-release cycling.This study showcased new possibilities of incorporating biobased lignin nanospheres in energy storage devices to fabricate stretchable devices leveraging synergies among various two-dimensional nanomaterials.展开更多
Ionic liquids(ILs)are promising electrolytes of supercapacitors for high voltage tolerance,zero vapor pressure,excellent thermal stability and environmental friendliness.However,the high viscosity and low ion mobility...Ionic liquids(ILs)are promising electrolytes of supercapacitors for high voltage tolerance,zero vapor pressure,excellent thermal stability and environmental friendliness.However,the high viscosity and low ion mobility of ILs limit the capacitance and high-rate performance of the devices.Rather than relying on black-box predictions and screening of advanced ILs for supercapacitors,machine learning models informed by experimentally derived physicochemical parameters can achieve significantly higher accuracy and relevance.According to the comprehensive experimental and data-driven investigation based on electrochemical characterization,nuclear magnetic resonance(NMR)dynamics,quantum and molecular dynamics simulations,we reveal an effective boosting of the specific capacity based on the water solvation mechanism in hydrophilic ILs.We then apply chemistry-informed machine learning to inverse screening and design ILs for supercapacitors based on the critical experimental parameters and morgan fingerprints.These findings elucidate the efficiency and mutual reinforcement of experimental and data-driven investigations in discovering promising materials for energy storage and conversion devices.展开更多
Improving the volumetric energy density of supercapacitors is essential for practical applications,which highly relies on the dense storage of ions in carbon-based electrodes.The functional units of carbon-based elect...Improving the volumetric energy density of supercapacitors is essential for practical applications,which highly relies on the dense storage of ions in carbon-based electrodes.The functional units of carbon-based electrode exhibit multi-scale structural characteristics including macroscopic electrode morphologies,mesoscopic microcrystals and pores,and microscopic defects and dopants in the carbon basal plane.Therefore,the ordered combination of multi-scale structures of carbon electrode is crucial for achieving dense energy storage and high volumetric performance by leveraging the functions of various scale structu re.Considering that previous reviews have focused more on the discussion of specific scale structu re of carbon electrodes,this review takes a multi-scale perspective in which recent progresses regarding the structureperformance relationship,underlying mechanism and directional design of carbon-based multi-scale structures including carbon morphology,pore structure,carbon basal plane micro-environment and electrode technology on dense energy storage and volumetric property of supercapacitors are systematically discussed.We analyzed in detail the effects of the morphology,pore,and micro-environment of carbon electrode materials on ion dense storage,summarized the specific effects of different scale structures on volumetric property and recent research progress,and proposed the mutual influence and trade-off relationship between various scale structures.In addition,the challenges and outlooks for improving the dense storage and volumetric performance of carbon-based supercapacitors are analyzed,which can provide feasible technical reference and guidance for the design and manufacture of dense carbon-based electrode materials.展开更多
This study explores the potential of Michelia champaca wood as a sustainable and locally available precursor for the fabrication of high-performance supercapacitor electrodes.Activated carbons were synthesized through...This study explores the potential of Michelia champaca wood as a sustainable and locally available precursor for the fabrication of high-performance supercapacitor electrodes.Activated carbons were synthesized through single-step carbonization at 400℃ and 500℃(SSC-400℃ and SSC-500℃) and double-step carbonization at 400℃(DSC-400℃),with all samples activated using H_(3)PO_(4).The effects of carbonization stratergy on the structural,morphological,and electrochemical characteristics of the resulting carbon materials were systematically evaluated,using techniques such as BET,SEM,TEM,XRD,Raman scattering,FTIR,CV,GCD and EIS.Among the samples,SSC-400℃ exhibited the best electrochemical performance,achieving a specific capacitance of 292.2 Fg^(-1),an energy density of 6.4 Wh kg^(-1),and a power density of 198.4 W kg^(-1).This superior performance is attributed to its optimized pore structure,improved sur-face functionality and enhanced conductivity.SSC-500℃showed marginally lower performance,whereas,DSC-400℃ displayed the least favorable results,indicating that double-step carbonization process may negatively affect material quality by disrupting the pore network.This work highlights a strong correlation between synthesis methodology and electrochemical efficiency,directly reinforcing the importance of process optimization in electrode material develop-ment.The findings contribute to the broader goal of developing cost-effective,renewable and environmentally friendly energy storage systems.By valorizing biomass waste,the study supports global movements toward green energy technologies and circular carbon economies,offering a viable pathway for sustainable supercapacitor development and practical applications in energy storage devices.展开更多
Thick electrodes can reduce the ratio of inactive constituents in a holistic energy storage system while improving energy and power densities.Unfortunately,traditional slurry-casting electrodes induce high-tortuous io...Thick electrodes can reduce the ratio of inactive constituents in a holistic energy storage system while improving energy and power densities.Unfortunately,traditional slurry-casting electrodes induce high-tortuous ionic diffusion routes that directly depress the capacitance with a thickening design.To overcome this,a novel 3D low-tortuosity,self-supporting,wood-structured ultrathick electrode(NiMoN@WC,a thickness of~1400 mm)with hierarchical porosity and artificial array-distributed small holes was constructed via anchoring bimetallic nitrides into the monolithic wood carbons.Accompanying the embedded NiMoN nanoclusters with well-designed geometric and electronic structure,the vertically low-tortuous channels,enlarged specific surface area and pore volume,superhydrophilic interface,and excellent charge conductivities,a superior capacitance of NiMoN@WC thick electrodes(~5350 mF cm^(-2)and 184.5 F g^(-1))is achieved without the structural deformation.In especial,monolithic wood carbons with gradient porous network not only function as the high-flux matrices to ameliorate the NiMoN loading via cell wall engineering but also allow fully-exposed electroactive substance and efficient current collection,thereby deliver an acceptable rate capability over 75%retention even at a high sweep rate of 20 mA cm^(-2).Additionally,an asymmetric NiMoN@WC//WC supercapacitor with an available working voltage of 1.0-1.8 V is assembled to demonstrate a maximum energy density of~2.04 mWh cm^(-2)(17.4 Wh kg^(-1))at a power density of 1620 mW cm^(-2),along with a decent long-term lifespan over 10,000 charging-discharging cycles.As a guideline,the rational design of wood ultrathick electrode with nanostructured transition metal nitrides sketch a promising blueprint for alleviating global energy scarcity while expanding carbon-neutral technologies.展开更多
Porous carbons hold broad application prospects in the domains of electrochemical energy storage devices and sensors.In this study,porous carbon derived from sodium alginate-encapsulated ZIF-8(SA/ZIF-8-C)was suc-cessf...Porous carbons hold broad application prospects in the domains of electrochemical energy storage devices and sensors.In this study,porous carbon derived from sodium alginate-encapsulated ZIF-8(SA/ZIF-8-C)was suc-cessfully prepared by blending ZIF-8 particles with sodium alginate,forming hydrogel beads in the presence of divalent metal ions,and subsequently subjecting them to high-temperature pyrolysis.Various characterization techniques were employed to evaluate the properties of the prepared materials.The introduction of a carbon framework on ZIF-8-derived particles effectively enhanced the conductivity of the prepared materials.The SA/ZIF-8(1.0)-C sample heated at 800℃exhibited a specific capacitance of up to 208 F g^(-1)at a current density of 0.5 A g^(-1)and outstanding cyclic stability.Even after 10,000 charge and discharge cycles,its capacitance retention rate remained as high as 87.14%.The symmetric supercapacitor constructed with the composite demonstrated an excellent energy density of 14.58 Wh kg^(-1)at a power capacity of 403.85 W kg^(-1).The implementation of this study provides new ideas and inspiration for the development of high-performance supercapacitors.展开更多
Poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate)(PEDOT:PSS)is a highly successful conductive polymer utilized as an electrode material in energy storage units for portable and wearable electronic de-vices.Neve...Poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate)(PEDOT:PSS)is a highly successful conductive polymer utilized as an electrode material in energy storage units for portable and wearable electronic de-vices.Nevertheless,employing PEDOT:PSS in supercapacitors(SC)in its pristine state presents challenges due to its suboptimal electrochemical performance and operational instability.To surmount these limita-tions,PEDOT:PSS has been integrated with carbon-based materials to form flexible electrodes,which ex-hibit physical and chemical stability during SC operation.We developed a streamlined fabrication process for high-performance SC electrodes composed of PEDOT:PSS and carbon quantum dots(CQDs).The CQDs were synthesized under microwave irradiation,yielding green-and red-light emissions.Through optimiz-ing the ratios of CQDs to PEDOT:PSS,the SC electrodes were prepared using a spray-coating technique,marking a significant improvement in device performance with a high volumetric capacitance(104.10 F cm-3),impressive energy density(19.68 Wh cm^(-3)),and excellent cyclic stability,retaining~85% of its original volumetric capacitance after 15,000 repeated GCD cycles.Moreover,the SCs,when utilized as a flexible substrate,demonstrated the ability to maintain up to~85% of their electrochemical performance even after 3,000 bending cycles(at a bending angle of 60°).These attributes render this hybrid composite an ideal candidate for a lightweight smart energy storage component in portable and wearable electronic technologies.展开更多
Delafossite AgFeO_(2)nanoparticles with a mixture of 2H and 3R phases were successfully fabricated by using a simple co-precipitation method.The resulting precursor was calcined at temperatures of 100,200,300,400,and ...Delafossite AgFeO_(2)nanoparticles with a mixture of 2H and 3R phases were successfully fabricated by using a simple co-precipitation method.The resulting precursor was calcined at temperatures of 100,200,300,400,and 500℃to obtain the delafossite AgFe0_(2)phase.The morphology and microstructure of the prepared AgFeO_(2)samples were characterized by using field emission scanning electron microscopy(FESEM),transmission electron microscopy(TEM),N_(2) adsorption/desorption,X-ray absorption spectroscopy(XAS),and Xray photoelectron spectroscopy(XPS)techniques.A three-electrode system was employed to investigate the electrochemical properties of the delafossite AgFeO_(2)nanoparticles in a 3 M KOH electrolyte.The delafossite AgFeO_(2)nanoparticles calcined at 100℃(AFO100)exhibited the highest surface area of 28.02 m^(2)·g^(-1)and outstanding electrochemical performance with specific capacitances of 229.71 F·g^(-1)at a current density of 1 A·g^(-1)and 358.32 F·g^(-1)at a scan rate of 2 mV·s^(-1).This sample also demonstrated the capacitance retention of 82.99% after 1000 charge/discharge cycles,along with superior specific power and specific energy values of 797.46 W·kg^(-1)and 72.74Wh·kg^(-1),respectively.These findings indicate that delafossite AgFeO_(2)has great potential as an electrode material for supercapacitor applications.展开更多
Herein,we report a simple self-charging hybrid power system(SCHPS)based on binder-free zinc copper selenide nanostructures(ZnCuSe_(2) NSs)deposited carbon fabric(CF)(i.e.,ZnCuSe_(2)/CF),which is used as an active mate...Herein,we report a simple self-charging hybrid power system(SCHPS)based on binder-free zinc copper selenide nanostructures(ZnCuSe_(2) NSs)deposited carbon fabric(CF)(i.e.,ZnCuSe_(2)/CF),which is used as an active material in the fabrication of supercapacitor(SC)and triboelectric nanogenerator(TENG).At first,a binder-free ZnCuSe_(2)/CF was synthesized via a simple and facial hydrothermal synthesis approach,and the electrochemical properties of the obtained ZnCuSe_(2)/CF were evaluated by fabricating a symmetric quasi-solid-state SC(SQSSC).The ZCS-2(Zn:Cu ratio of 2:1)material deposited CF-based SQSSC exhibited good electrochemical properties,and the obtained maximum energy and power densities were 7.5 Wh kg^(-1)and 683.3 W kg^(-1),respectively with 97.6%capacitance retention after 30,000 cycles.Furthermore,the ZnCuSe_(2)/CF was coated with silicone rubber elastomer using a doctor blade technique,which is used as a negative triboelectric material in the fabrication of the multiple TENG(M-TENG).The fabricated M-TENG exhibited excellent electrical output performance,and the robustness and mechanical stability of the device were studied systematically.The practicality and applicability of the proposed M-TENG and SQSSC were systematically investigated by powering various low-power portable electronic components.Finally,the SQSSC was combined with the M-TENG to construct a SCHPS.The fabricated SCHPS provides a feasible solution for sustainable power supply,and it shows great potential in self-powered portable electronic device applications.展开更多
With the development of electronics and portable devices,there is a significant drive to develop electrode materials for supercapacitors that are lightweight,economical,and provide high energy and power densities.Lign...With the development of electronics and portable devices,there is a significant drive to develop electrode materials for supercapacitors that are lightweight,economical,and provide high energy and power densities.Lignin-based porous carbons have recently been extensively studied for en-ergy storage applications because of their characteristics of large specific surface area,easy doping,and high conductivity.Significant progress in the synthesis of porous carbons derived from lignin,using different strategies for their preparation and modification with heteroatoms,metal oxides,met-al sulfides,and conductive polymers is considered and their electrochemical performances and ion storage mechanisms are discussed.Considerable fo-cus is directed towards the challenges encountered in using lignin-based por-ous carbons and the ways to optimize specific capacity and energy density for supercapacitor applications.Finally,the limitations of existing technolo-gies and research directions for improving the performance of lignin-based carbons are discussed.展开更多
The ability to control the preparation of one-dimensional(1D)porous carbon nanorods,especially during rapid polymerization,is key to their practical application.We report a method for synthesizing 1D porous carbon nan...The ability to control the preparation of one-dimensional(1D)porous carbon nanorods,especially during rapid polymerization,is key to their practical application.We report a method for synthesizing 1D porous carbon nanorods,characterized by the formation of rod-like mi-celles that are assembled from sodium palmitate and Pluronic F127,facilitated by protonated melamine,and subsequently converted into melamine-based N-doped polymer nanorods which were carbonized to produce the corres-ponding N-doped carbon nanorods.The specific capacitance of the supercapacitor used the as-pre-pared N-doped nanorods as electrode material in a three-electrode system was calculated to be 301.66 F g^(-1) at a current density of 0.2 A g^(-1),with an ultra-high specific surface area normalized capacitance of up to 67.07μF cm^(-2).The N-doping and their one-dimensionality give the nanorods a low internal resistance and good stability,making them well suited for fundamental studies and practical applications ranging from materials chemistry to electrochemical energy storage.展开更多
A low-cost 1D cobalt-based coordination polymer(CP)[Co(BGPD)(DMSO)_(2)(H_(2)O)_(2)](Co-BD;H2BGPD=N,N'-bis(glycinyl)pyromellitic diimide;DMSO=dimethyl sulfoxide)was synthesized by a simple method,and its crystal st...A low-cost 1D cobalt-based coordination polymer(CP)[Co(BGPD)(DMSO)_(2)(H_(2)O)_(2)](Co-BD;H2BGPD=N,N'-bis(glycinyl)pyromellitic diimide;DMSO=dimethyl sulfoxide)was synthesized by a simple method,and its crystal structure was characterized.In a three-electrode system,Co-BD,as the electrode material for supercapacitors,achieved a specific capacitance of 830 F·g^(-1)at 1 A·g^(-1),equivalent to a specific capacity of 116.4 mAh·g^(-1),and exhibited high-rate capability,reaching 212 F·g^(-1)at 20 A·g^(-1).Impressively,Co-BD||rGO(reduced graphene oxide),representing an asymmetrical supercapacitor,owns a higher energy density of 14.2 Wh·kg^(-1)at 0.80 kW·kg^(-1),and an excellent cycle performance(After 4000 cycles at 1 A·g^(-1),the capacitance retention was up to 94%).CCDC:2418872.展开更多
Introduction High-entropy oxides(HEOs)have attracted much attention in the field of electrochemistry due to their distinctive structural characteristics and unique properties.The multiple-principal elements in HEOs of...Introduction High-entropy oxides(HEOs)have attracted much attention in the field of electrochemistry due to their distinctive structural characteristics and unique properties.The multiple-principal elements in HEOs offer the multiple redox pairs and multiple possible active sites,which can enhance the energy storage capacity and the electrocatalytic performance.Although the notable progress is achieved in the development of HEOs electrodes,their electrochemical properties should be further improved to meet the requirements of high-performance supercapacitors and OER electrocatalysts.The abundant active sites for the Faradic redox reactions and short pathways for charge transportation could be constructed through the design of novel HEOs with advanced microstructures,thus improving the electrochemical properties.As advanced microstructures,a hollow structure has a great promise for energy storage and conversion because it can provide more accessible storage sites,more catalytic centers and a larger electrode/electrolyte contact area.It is thus expected that the construction of hollow structure is an alternative route to significantly promote the electrochemical properties of HEOs electrode materials.However,it is difficult to prepare the HEOs with a hollow structure due to the complexity of the high-entropy system.In this work,a hollow spherical high-entropy perovskite oxide of La(Cr_(0.2)Mn_(0.2)Fe_(0.2)Ni_(0.2)Cu_(0.2))O_(3)(HS-HEPs)was prepared by microwave solvothermal process and subsequent calcination treatment.The as-prepared HS-HEPs exhibited the excellent electrochemical performance when used as an electrode material for supercapacitors and OER electrocatalysts due to the advantages resulted from the combination of high-entropy perovskite and special hollow structure.Methods HS-HEPs were prepared by microwave solvothermal process and subsequent calcination treatment.Typically,0.134 mmol Cr(NO_(3))_(3)·6H_(2)O,0.134 mmol Mn(NO_(3))_(2)·4H_(2)O,0.134 mmol Fe(NO_(3))_(3)·9H_(2)O,0.134 mmol Ni(NO_(3))_(2)·6H_(2)O,0.134 mmol Cu(NO_(3))_(2)·3H_(2)O,and 0.5 mmol La(NO_(3))_(3)·6H_(2)O were dissolved in 30 mL ethanol under stirring for 1 h to obtain the homogeneous solution.Afterwards,60 mg of carbon spheres were added in the solution under ultrasonic treatment for 30 min.The resulting mixture was transferred to a 50 mL microwave digestion vessel.The vessel was heated in a microwave oven at a power of 210 W for 10 min.Subsequently,the obtained mixture was centrifuged,washed with deionized water,and dried in a vacuum drying oven at 70℃for 12 h.Finally,the obtained precursor powder was calcinated in a tube furnace with a heating rate of 3℃/min at 650℃for 2 h to acquire HS-HEPs.The crystalline structure of the sample was determined by X-ray diffraction(XRD,D8 Davinci,Bruker Co.,Germany).The morphology and microstructure of sample were characterized by field-emission scanning electron microscopy(FESEM,S-4800,Hitachi Co.Ltd.,Japan)equipped with energy dispersive X-ray spectroscopy(EDS)and transmission electron microscopy(TEM,2100F,JEOL Co.,Japan).The X-ray photoelectron spectra were obtained by a X-ray photoelectron spectrometry(XPS,ESCALab 250,Thermo VG Co.,USA).The supercapacitor and OER performance of the sample were measured on a CHI 660E electrochemical workstation(Shanghai Chenhua Instrument Co.,China).Results and discussion The as-prepared samples display a cubic perovskite crystalline structure and a hollow sphere morphology.According to the XPS analysis,the variable oxidation states of Cr,Fe and Mn present in the HS-HEPs,which benefits the Faradaic redox reactions and increases the capacitance.In addition,the existence of high concentration of oxygen vacancies in HS-HEPs is beneficial to enhancing the capacitance and OER activity.Based on the GCD curve,the specific capacitance of HS-HEPs is estimated to be 406 F/g at 1 A/g.After GCD cycles of 5000 at a current density of 5 A/g,65%capacitance is retained,implying a good long-term electrochemical stability.An asymmetric supercapacitor device(HS-HEPs//AC)with a two electrode configuration is assembled.A maximum energy density of 39.4 W·h/kg is achieved at power density of 746 W/kg.The OER activity of HS-HEPs is evaluated by a linear sweep voltammetry(LSV)polarization curve in 1 mol/L KOH aqueous solution using a standard three-electrode system.The overpotential of HS-HEPs is identified as 347 mV versus RHE for achieving a current density of 10 mA/cm^(2),which is smaller than that of commercial IrO2(372 mV).The HS-HEPs possess the excellent electrochemical performance,which can be ascribed to the high specific surface area,abundant active sites,and high oxygen vacancy content,resulting from the combination of high-entropy perovskite and special hollow structure.Conclusions High-entropy La(Cr_(0.2)Mn_(0.2)Fe_(0.2)Ni_(0.2)Cu_(0.2))O_(3)hollow spheres with a perovskite crystalline structure were prepared by microwave solvothermal process and subsequent calcination treatment.The HS-HEPs possessed the excellent electrochemical performance,which could be ascribed to the high specific surface area,abundant active sites,and high oxygen vacancy content,resulting from the combination of high-entropy perovskite and special hollow structure.Based on the electrochemical performance,HS-HEPs could be used as supercapacitor electrode material and OER electrocatalysts.This work could provide a strategy to design and prepare high-entropy oxides with a hollow sphere structure,having promising applications in energy storage and conversion.展开更多
Filter capacitors play an important role in altern-ating current(AC)-line filtering for stabilizing voltage,sup-pressing harmonics,and improving power quality.However,traditional aluminum electrolytic capacitors(AECs)...Filter capacitors play an important role in altern-ating current(AC)-line filtering for stabilizing voltage,sup-pressing harmonics,and improving power quality.However,traditional aluminum electrolytic capacitors(AECs)suffer from a large size,short lifespan,low power density,and poor reliability,which limits their use.In contrast,ultrafast supercapacitors(SCs)are ideal for replacing commercial AECs because of their extremely high power densities,fast charging and discharging,and excellent high-frequency re-sponse.We review the design principles and key parameters for ultrafast supercapacitors and summarize research pro-gress in recent years from the aspects of electrode materials,electrolytes,and device configurations.The preparation,structures,and frequency response performance of electrode materials mainly consisting of carbon materials such as graphene and carbon nanotubes,conductive polymers,and transition metal compounds,are focused on.Finally,future research directions for ultrafast SCs are suggested.展开更多
Due to its unique layered structure and excellent electrochemical properties,molybdenum disulfide(MoS_(2))demonstrates significant potential for applications in the energy storage field,particularly in supercapacitors...Due to its unique layered structure and excellent electrochemical properties,molybdenum disulfide(MoS_(2))demonstrates significant potential for applications in the energy storage field,particularly in supercapacitors.It is widely regarded as one of the most representative transition metal dichalcogenides.MoS_(2)possesses a high theoretical specific capacitance,abundant edge active sites,and favorable tunability and structural diversity,which provide it with a distinct advantage in the construction of advanced electrode structures.Additionally,the anisotropic characteristics of MoS_(2)concerning electron and ion transport offer more dimensions for regulating its electrochemical behavior.This work will systematically review various synthesis strategies for MoS_(2)and its recent advancements in energy storage,with a particular focus on the mechanisms by which interlayer spacing modulation affects energy storage behavior in supercapacitor configurations.The discussion will encompass a comprehensive logical framework that spans material structure modifications,electronic configuration evolution,and enhancements in macroscopic device performance.This review aims to provide theoretical support and practical guidance for the application of MoS_(2)in the next generation of highperformance energy storage devices.展开更多
In order to meet the demands of new-generation electric vehicles that require high power output(over 15 kW/kg),it is crucial to increase the energy density of car-bon-based supercapacitors to a level comparable to tha...In order to meet the demands of new-generation electric vehicles that require high power output(over 15 kW/kg),it is crucial to increase the energy density of car-bon-based supercapacitors to a level comparable to that of batteries,while maintaining a high power density.We re-port a porous carbon material produced by immersing pop-lar wood(PW)sawdust in a solution of KOH and graphene oxide(GO),followed by carbonization.The resulting mater-ial has exceptional properties as an electrode for high-en-ergy supercapacitors.Compared to the material prepared by the direct carbonization of PW,its electrical conductivity was in-creased from 0.36 to 26.3 S/cm.Because of this and a high microporosity of over 80%,which provides fast electron channels and a large ion storage surface,when used as the electrodes for a symmetric supercapacitor,it gave a high energy density of 27.9 Wh/kg@0.95 kW/kg in an aqueous electrolyte of 1.0 mol/L Na_(2)SO_(4).The device also had battery-level energy storage with maximum energy densities of 73.9 Wh/kg@2.0 kW/kg and 67.6 Wh/kg@40 kW/kg,an ultrahigh power density,in an organic electrolyte of 1.0 mol/L TEABF4/AN.These values are comparable to those of 30−45 Wh/kg for Pb-acid batteries and 30−55 Wh/kg for aqueous lithium batteries.This work indicates a way to prepare carbon materials that can be used in supercapacit-ors with ultrahigh energy and power densities.展开更多
基金granted by the National Natural Science Foundation of China(Nos.52533008,21835003,62274097,and 62004106)National Key Research and Development Program of China(Nos.2024YFB3612500,2024YFB3612600,and 2023YFB3608900)+2 种基金Basic Research Program of Jiangsu Province(No.BK20243057)Postgraduate Research&Practice Innovation Program of Jiangsu Province(No.KYCX25_1213)the Natural Science Foundation of Nanjing Universityof Posts and Telecommunications(No.NY225135).
文摘To meet the growing needs of flexible and wearable electronics,stretchable energy storage devices—especially supercapacitors(SCs)—have become a key focus in advanced energy storage research.However,achieving both mechanical stretchability and high capacitance in SC still faces great challenges,and the crucial factors lie in creating superior electrode materials that exhibit high electrochemical performance as well as excellent mechanical stretchability.Covalent organic frameworks(COFs)possess considerable potential as electrode materials for SCs by virtue of stable organic frameworks,open channels and designable functional groups.Nevertheless,their applications in flexible SCs are greatly hindered by their rigid characteristics.Here a novel COFs@conductive polymer hydrogels(CPHs)@poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate)(PEDOT:PSS)complexes,which integrate the pseudocapacitance of PDITAPA COF,mechanical stretchability of hydrogels and high conductivity of PEDOT:PSS,has been developed as stretchable electrode of SCs.Physically cross-linked PEDOT nanofibers,with their interlinked and entangled architecture,collectively boost mechanical,electrical,and electrochemical performance.The COFs@CPHs@PEDOT:PSS simultaneously demonstrates outstanding mechanical stretchability,high electrical behaviors,and superior swelling characteristics.The resulting SC exhibits advantages of simple structures,facile assembly processes,high specific capacitance,excellent cycling stability,and arbitrary deformation,which holds great application prospects for wearable electronic products.Owing to its uncomplicated structure,ease of production,high energy storage capacity,robust cycling performance,and adaptability to deformation,this fabricated SC is well-suited for next-generation wearable technologies.
基金financial support of the TMA pai scholarship from the Manipal Institute of Technology,Manipal Academy of Higher Education,Manipal,in achieving this milestone。
文摘Graphitic carbon nitride(g-C_(3)N_(4)),known for its green and abundant nature and composed of carbon and nitrogen in a two-dimensional structure,has emerged as a significant area of interest across various disciplines,particularly in energy conversion and storage.Its recent demonstrations of high potential in supercapacitor applications mark it as a promising alternative to graphene within the realm of materials science.Numerous favorable features,such as chemical and thermal stability,abundant nitrogen content,eco-friendly attributes,and gentle conditions for synthesis,are shown.This review summarizes recent advancements in the use of g-C_(3)N_(4)and its composites as electrodes for supercapacitors,highlighting the advantages and issues associated with g-C_(3)N_(4)in these applications.This emphasizes situations where the composition of g-C_(3)N_(4)with other materials,such as metal oxides,metal chalcogenides,carbon materials,and conducting polymers,overcomes its limitations,leading to composite materials with improved functionalities.This review discusses the challenges that still need to be addressed and the possible future roles of g-C_(3)N_(4)in the research of advanced supercapacitor technology,such as battery-hybrid supercapacitors,flexible supercapacitors,and photo-supercapacitors.
文摘Supercapacitors are gaining popularity due to their high cycling stability,power density,and fast charge and discharge rates.Researchers are ex-ploring electrode materials,electrolytes,and separat-ors for cost-effective energy storage systems.Ad-vances in materials science have led to the develop-ment of hybrid nanomaterials,such as combining fil-amentous carbon forms with inorganic nanoparticles,to create new charge and energy transfer processes.Notable materials for electrochemical energy-stor-age applications include MXenes,2D transition met-al carbides,and nitrides,carbon black,carbon aerogels,activated carbon,carbon nanotubes,conducting polymers,carbon fibers,and nanofibers,and graphene,because of their thermal,electrical,and mechanical properties.Carbon materials mixed with conducting polymers,ceramics,metal oxides,transition metal oxides,metal hydroxides,transition metal sulfides,trans-ition metal dichalcogenide,metal sulfides,carbides,nitrides,and biomass materials have received widespread attention due to their remarkable performance,eco-friendliness,cost-effectiveness,and renewability.This article explores the development of carbon-based hybrid materials for future supercapacitors,including electric double-layer capacitors,pseudocapacitors,and hy-brid supercapacitors.It investigates the difficulties that influence structural design,manufacturing(electrospinning,hydro-thermal/solvothermal,template-assisted synthesis,electrodeposition,electrospray,3D printing)techniques and the latest car-bon-based hybrid materials research offer practical solutions for producing high-performance,next-generation supercapacitors.
基金supported by Natural Science and Engineering Research Council of Canada(RGPIN-2017-06737)Canada Research Chairs program,the National Key Research and Development Program of China(2017YFD0601005,2022YFD0904201)+1 种基金the National Natural Science Foundation of China(51203075)the China Scholarship Council(Grant No.CSC202208320361).
文摘With the rapid development of flexible wearable electronics,the demand for stretchable energy storage devices has surged.In this work,a novel gradient-layered architecture was design based on single-pore hollow lignin nanospheres(HLNPs)-intercalated two-dimensional transition metal carbide(Ti_(3)C_(2)T_(x) MXene)for fabricating highly stretchable and durable supercapacitors.By depositing and inserting HLNPs in the MXene layers with a bottom-up decreasing gradient,a multilayered porous MXene structure with smooth ion channels was constructed by reducing the overstacking of MXene lamella.Moreover,the micro-chamber architecture of thin-walled lignin nanospheres effectively extended the contact area between lignin and MXene to improve ion and electron accessibility,thus better utilizing the pseudocapacitive property of lignin.All these strategies effectively enhanced the capacitive performance of the electrodes.In addition,HLNPs,which acted as a protective phase for MXene layer,enhanced mechanical properties of the wrinkled stretchable electrodes by releasing stress through slip and deformation during the stretch-release cycling and greatly improved the structural integrity and capacitive stability of the electrodes.Flexible electrodes and symmetric flexible all-solid-state supercapacitors capable of enduring 600%uniaxial tensile strain were developed with high specific capacitances of 1273 mF cm^(−2)(241 F g^(−1))and 514 mF cm^(−2)(95 F g^(−1)),respectively.Moreover,their capacitances were well preserved after 1000 times of 600%stretch-release cycling.This study showcased new possibilities of incorporating biobased lignin nanospheres in energy storage devices to fabricate stretchable devices leveraging synergies among various two-dimensional nanomaterials.
基金supported by the National Natural Science Foundation of China(92372126,52373203)the Excellent Young Scientists Fund Programthe AI for Science Foundation of Fudan University(FudanX24AI014)。
文摘Ionic liquids(ILs)are promising electrolytes of supercapacitors for high voltage tolerance,zero vapor pressure,excellent thermal stability and environmental friendliness.However,the high viscosity and low ion mobility of ILs limit the capacitance and high-rate performance of the devices.Rather than relying on black-box predictions and screening of advanced ILs for supercapacitors,machine learning models informed by experimentally derived physicochemical parameters can achieve significantly higher accuracy and relevance.According to the comprehensive experimental and data-driven investigation based on electrochemical characterization,nuclear magnetic resonance(NMR)dynamics,quantum and molecular dynamics simulations,we reveal an effective boosting of the specific capacity based on the water solvation mechanism in hydrophilic ILs.We then apply chemistry-informed machine learning to inverse screening and design ILs for supercapacitors based on the critical experimental parameters and morgan fingerprints.These findings elucidate the efficiency and mutual reinforcement of experimental and data-driven investigations in discovering promising materials for energy storage and conversion devices.
基金funded by the Joint Fund for Regional Innovation and Development of National Natural Science Foundation of China(U21A20143)the National Science Fund for Excellent Young Scholars(52322607)the Excellent Youth Foundation of Heilongjiang Scientific Committee(YQ2022E028)。
文摘Improving the volumetric energy density of supercapacitors is essential for practical applications,which highly relies on the dense storage of ions in carbon-based electrodes.The functional units of carbon-based electrode exhibit multi-scale structural characteristics including macroscopic electrode morphologies,mesoscopic microcrystals and pores,and microscopic defects and dopants in the carbon basal plane.Therefore,the ordered combination of multi-scale structures of carbon electrode is crucial for achieving dense energy storage and high volumetric performance by leveraging the functions of various scale structu re.Considering that previous reviews have focused more on the discussion of specific scale structu re of carbon electrodes,this review takes a multi-scale perspective in which recent progresses regarding the structureperformance relationship,underlying mechanism and directional design of carbon-based multi-scale structures including carbon morphology,pore structure,carbon basal plane micro-environment and electrode technology on dense energy storage and volumetric property of supercapacitors are systematically discussed.We analyzed in detail the effects of the morphology,pore,and micro-environment of carbon electrode materials on ion dense storage,summarized the specific effects of different scale structures on volumetric property and recent research progress,and proposed the mutual influence and trade-off relationship between various scale structures.In addition,the challenges and outlooks for improving the dense storage and volumetric performance of carbon-based supercapacitors are analyzed,which can provide feasible technical reference and guidance for the design and manufacture of dense carbon-based electrode materials.
文摘This study explores the potential of Michelia champaca wood as a sustainable and locally available precursor for the fabrication of high-performance supercapacitor electrodes.Activated carbons were synthesized through single-step carbonization at 400℃ and 500℃(SSC-400℃ and SSC-500℃) and double-step carbonization at 400℃(DSC-400℃),with all samples activated using H_(3)PO_(4).The effects of carbonization stratergy on the structural,morphological,and electrochemical characteristics of the resulting carbon materials were systematically evaluated,using techniques such as BET,SEM,TEM,XRD,Raman scattering,FTIR,CV,GCD and EIS.Among the samples,SSC-400℃ exhibited the best electrochemical performance,achieving a specific capacitance of 292.2 Fg^(-1),an energy density of 6.4 Wh kg^(-1),and a power density of 198.4 W kg^(-1).This superior performance is attributed to its optimized pore structure,improved sur-face functionality and enhanced conductivity.SSC-500℃showed marginally lower performance,whereas,DSC-400℃ displayed the least favorable results,indicating that double-step carbonization process may negatively affect material quality by disrupting the pore network.This work highlights a strong correlation between synthesis methodology and electrochemical efficiency,directly reinforcing the importance of process optimization in electrode material develop-ment.The findings contribute to the broader goal of developing cost-effective,renewable and environmentally friendly energy storage systems.By valorizing biomass waste,the study supports global movements toward green energy technologies and circular carbon economies,offering a viable pathway for sustainable supercapacitor development and practical applications in energy storage devices.
基金support from the National Natural Science Foundation of China(32171728)Wuhan Knowledge Innovation Project(2022020801020312).
文摘Thick electrodes can reduce the ratio of inactive constituents in a holistic energy storage system while improving energy and power densities.Unfortunately,traditional slurry-casting electrodes induce high-tortuous ionic diffusion routes that directly depress the capacitance with a thickening design.To overcome this,a novel 3D low-tortuosity,self-supporting,wood-structured ultrathick electrode(NiMoN@WC,a thickness of~1400 mm)with hierarchical porosity and artificial array-distributed small holes was constructed via anchoring bimetallic nitrides into the monolithic wood carbons.Accompanying the embedded NiMoN nanoclusters with well-designed geometric and electronic structure,the vertically low-tortuous channels,enlarged specific surface area and pore volume,superhydrophilic interface,and excellent charge conductivities,a superior capacitance of NiMoN@WC thick electrodes(~5350 mF cm^(-2)and 184.5 F g^(-1))is achieved without the structural deformation.In especial,monolithic wood carbons with gradient porous network not only function as the high-flux matrices to ameliorate the NiMoN loading via cell wall engineering but also allow fully-exposed electroactive substance and efficient current collection,thereby deliver an acceptable rate capability over 75%retention even at a high sweep rate of 20 mA cm^(-2).Additionally,an asymmetric NiMoN@WC//WC supercapacitor with an available working voltage of 1.0-1.8 V is assembled to demonstrate a maximum energy density of~2.04 mWh cm^(-2)(17.4 Wh kg^(-1))at a power density of 1620 mW cm^(-2),along with a decent long-term lifespan over 10,000 charging-discharging cycles.As a guideline,the rational design of wood ultrathick electrode with nanostructured transition metal nitrides sketch a promising blueprint for alleviating global energy scarcity while expanding carbon-neutral technologies.
基金supports from the National Natural Science Foundation of China(22075034,22178037,and 22478047)Natural Science Foundation of Liaoning Province of China(2021-MS-303)the China Scholarship Council(CSC No 202008210171).
文摘Porous carbons hold broad application prospects in the domains of electrochemical energy storage devices and sensors.In this study,porous carbon derived from sodium alginate-encapsulated ZIF-8(SA/ZIF-8-C)was suc-cessfully prepared by blending ZIF-8 particles with sodium alginate,forming hydrogel beads in the presence of divalent metal ions,and subsequently subjecting them to high-temperature pyrolysis.Various characterization techniques were employed to evaluate the properties of the prepared materials.The introduction of a carbon framework on ZIF-8-derived particles effectively enhanced the conductivity of the prepared materials.The SA/ZIF-8(1.0)-C sample heated at 800℃exhibited a specific capacitance of up to 208 F g^(-1)at a current density of 0.5 A g^(-1)and outstanding cyclic stability.Even after 10,000 charge and discharge cycles,its capacitance retention rate remained as high as 87.14%.The symmetric supercapacitor constructed with the composite demonstrated an excellent energy density of 14.58 Wh kg^(-1)at a power capacity of 403.85 W kg^(-1).The implementation of this study provides new ideas and inspiration for the development of high-performance supercapacitors.
基金supported by the National Research Foundation of Korea(NRF)through a grant provided by the Korean government(No.NRF-2021R1F1A1063451).
文摘Poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate)(PEDOT:PSS)is a highly successful conductive polymer utilized as an electrode material in energy storage units for portable and wearable electronic de-vices.Nevertheless,employing PEDOT:PSS in supercapacitors(SC)in its pristine state presents challenges due to its suboptimal electrochemical performance and operational instability.To surmount these limita-tions,PEDOT:PSS has been integrated with carbon-based materials to form flexible electrodes,which ex-hibit physical and chemical stability during SC operation.We developed a streamlined fabrication process for high-performance SC electrodes composed of PEDOT:PSS and carbon quantum dots(CQDs).The CQDs were synthesized under microwave irradiation,yielding green-and red-light emissions.Through optimiz-ing the ratios of CQDs to PEDOT:PSS,the SC electrodes were prepared using a spray-coating technique,marking a significant improvement in device performance with a high volumetric capacitance(104.10 F cm-3),impressive energy density(19.68 Wh cm^(-3)),and excellent cyclic stability,retaining~85% of its original volumetric capacitance after 15,000 repeated GCD cycles.Moreover,the SCs,when utilized as a flexible substrate,demonstrated the ability to maintain up to~85% of their electrochemical performance even after 3,000 bending cycles(at a bending angle of 60°).These attributes render this hybrid composite an ideal candidate for a lightweight smart energy storage component in portable and wearable electronic technologies.
基金Suranaree University of Technology(SUT)Thailand Science,Research and Innovation(TSRI)National Science,Research and Innovation Fund(NSRF)(project cord.179314)。
文摘Delafossite AgFeO_(2)nanoparticles with a mixture of 2H and 3R phases were successfully fabricated by using a simple co-precipitation method.The resulting precursor was calcined at temperatures of 100,200,300,400,and 500℃to obtain the delafossite AgFe0_(2)phase.The morphology and microstructure of the prepared AgFeO_(2)samples were characterized by using field emission scanning electron microscopy(FESEM),transmission electron microscopy(TEM),N_(2) adsorption/desorption,X-ray absorption spectroscopy(XAS),and Xray photoelectron spectroscopy(XPS)techniques.A three-electrode system was employed to investigate the electrochemical properties of the delafossite AgFeO_(2)nanoparticles in a 3 M KOH electrolyte.The delafossite AgFeO_(2)nanoparticles calcined at 100℃(AFO100)exhibited the highest surface area of 28.02 m^(2)·g^(-1)and outstanding electrochemical performance with specific capacitances of 229.71 F·g^(-1)at a current density of 1 A·g^(-1)and 358.32 F·g^(-1)at a scan rate of 2 mV·s^(-1).This sample also demonstrated the capacitance retention of 82.99% after 1000 charge/discharge cycles,along with superior specific power and specific energy values of 797.46 W·kg^(-1)and 72.74Wh·kg^(-1),respectively.These findings indicate that delafossite AgFeO_(2)has great potential as an electrode material for supercapacitor applications.
基金supported by the National Research Foundation of Korea(NRF)grant funded by the Korean government(MSIP)(No.2018R1A6A1A03025708)partly supported by the GRRC program of Gyeonggi province(GRRCKyungHee2023-B03).
文摘Herein,we report a simple self-charging hybrid power system(SCHPS)based on binder-free zinc copper selenide nanostructures(ZnCuSe_(2) NSs)deposited carbon fabric(CF)(i.e.,ZnCuSe_(2)/CF),which is used as an active material in the fabrication of supercapacitor(SC)and triboelectric nanogenerator(TENG).At first,a binder-free ZnCuSe_(2)/CF was synthesized via a simple and facial hydrothermal synthesis approach,and the electrochemical properties of the obtained ZnCuSe_(2)/CF were evaluated by fabricating a symmetric quasi-solid-state SC(SQSSC).The ZCS-2(Zn:Cu ratio of 2:1)material deposited CF-based SQSSC exhibited good electrochemical properties,and the obtained maximum energy and power densities were 7.5 Wh kg^(-1)and 683.3 W kg^(-1),respectively with 97.6%capacitance retention after 30,000 cycles.Furthermore,the ZnCuSe_(2)/CF was coated with silicone rubber elastomer using a doctor blade technique,which is used as a negative triboelectric material in the fabrication of the multiple TENG(M-TENG).The fabricated M-TENG exhibited excellent electrical output performance,and the robustness and mechanical stability of the device were studied systematically.The practicality and applicability of the proposed M-TENG and SQSSC were systematically investigated by powering various low-power portable electronic components.Finally,the SQSSC was combined with the M-TENG to construct a SCHPS.The fabricated SCHPS provides a feasible solution for sustainable power supply,and it shows great potential in self-powered portable electronic device applications.
基金National Natural Science Foundation of China(22262034)。
文摘With the development of electronics and portable devices,there is a significant drive to develop electrode materials for supercapacitors that are lightweight,economical,and provide high energy and power densities.Lignin-based porous carbons have recently been extensively studied for en-ergy storage applications because of their characteristics of large specific surface area,easy doping,and high conductivity.Significant progress in the synthesis of porous carbons derived from lignin,using different strategies for their preparation and modification with heteroatoms,metal oxides,met-al sulfides,and conductive polymers is considered and their electrochemical performances and ion storage mechanisms are discussed.Considerable fo-cus is directed towards the challenges encountered in using lignin-based por-ous carbons and the ways to optimize specific capacity and energy density for supercapacitor applications.Finally,the limitations of existing technolo-gies and research directions for improving the performance of lignin-based carbons are discussed.
文摘The ability to control the preparation of one-dimensional(1D)porous carbon nanorods,especially during rapid polymerization,is key to their practical application.We report a method for synthesizing 1D porous carbon nanorods,characterized by the formation of rod-like mi-celles that are assembled from sodium palmitate and Pluronic F127,facilitated by protonated melamine,and subsequently converted into melamine-based N-doped polymer nanorods which were carbonized to produce the corres-ponding N-doped carbon nanorods.The specific capacitance of the supercapacitor used the as-pre-pared N-doped nanorods as electrode material in a three-electrode system was calculated to be 301.66 F g^(-1) at a current density of 0.2 A g^(-1),with an ultra-high specific surface area normalized capacitance of up to 67.07μF cm^(-2).The N-doping and their one-dimensionality give the nanorods a low internal resistance and good stability,making them well suited for fundamental studies and practical applications ranging from materials chemistry to electrochemical energy storage.
文摘A low-cost 1D cobalt-based coordination polymer(CP)[Co(BGPD)(DMSO)_(2)(H_(2)O)_(2)](Co-BD;H2BGPD=N,N'-bis(glycinyl)pyromellitic diimide;DMSO=dimethyl sulfoxide)was synthesized by a simple method,and its crystal structure was characterized.In a three-electrode system,Co-BD,as the electrode material for supercapacitors,achieved a specific capacitance of 830 F·g^(-1)at 1 A·g^(-1),equivalent to a specific capacity of 116.4 mAh·g^(-1),and exhibited high-rate capability,reaching 212 F·g^(-1)at 20 A·g^(-1).Impressively,Co-BD||rGO(reduced graphene oxide),representing an asymmetrical supercapacitor,owns a higher energy density of 14.2 Wh·kg^(-1)at 0.80 kW·kg^(-1),and an excellent cycle performance(After 4000 cycles at 1 A·g^(-1),the capacitance retention was up to 94%).CCDC:2418872.
文摘Introduction High-entropy oxides(HEOs)have attracted much attention in the field of electrochemistry due to their distinctive structural characteristics and unique properties.The multiple-principal elements in HEOs offer the multiple redox pairs and multiple possible active sites,which can enhance the energy storage capacity and the electrocatalytic performance.Although the notable progress is achieved in the development of HEOs electrodes,their electrochemical properties should be further improved to meet the requirements of high-performance supercapacitors and OER electrocatalysts.The abundant active sites for the Faradic redox reactions and short pathways for charge transportation could be constructed through the design of novel HEOs with advanced microstructures,thus improving the electrochemical properties.As advanced microstructures,a hollow structure has a great promise for energy storage and conversion because it can provide more accessible storage sites,more catalytic centers and a larger electrode/electrolyte contact area.It is thus expected that the construction of hollow structure is an alternative route to significantly promote the electrochemical properties of HEOs electrode materials.However,it is difficult to prepare the HEOs with a hollow structure due to the complexity of the high-entropy system.In this work,a hollow spherical high-entropy perovskite oxide of La(Cr_(0.2)Mn_(0.2)Fe_(0.2)Ni_(0.2)Cu_(0.2))O_(3)(HS-HEPs)was prepared by microwave solvothermal process and subsequent calcination treatment.The as-prepared HS-HEPs exhibited the excellent electrochemical performance when used as an electrode material for supercapacitors and OER electrocatalysts due to the advantages resulted from the combination of high-entropy perovskite and special hollow structure.Methods HS-HEPs were prepared by microwave solvothermal process and subsequent calcination treatment.Typically,0.134 mmol Cr(NO_(3))_(3)·6H_(2)O,0.134 mmol Mn(NO_(3))_(2)·4H_(2)O,0.134 mmol Fe(NO_(3))_(3)·9H_(2)O,0.134 mmol Ni(NO_(3))_(2)·6H_(2)O,0.134 mmol Cu(NO_(3))_(2)·3H_(2)O,and 0.5 mmol La(NO_(3))_(3)·6H_(2)O were dissolved in 30 mL ethanol under stirring for 1 h to obtain the homogeneous solution.Afterwards,60 mg of carbon spheres were added in the solution under ultrasonic treatment for 30 min.The resulting mixture was transferred to a 50 mL microwave digestion vessel.The vessel was heated in a microwave oven at a power of 210 W for 10 min.Subsequently,the obtained mixture was centrifuged,washed with deionized water,and dried in a vacuum drying oven at 70℃for 12 h.Finally,the obtained precursor powder was calcinated in a tube furnace with a heating rate of 3℃/min at 650℃for 2 h to acquire HS-HEPs.The crystalline structure of the sample was determined by X-ray diffraction(XRD,D8 Davinci,Bruker Co.,Germany).The morphology and microstructure of sample were characterized by field-emission scanning electron microscopy(FESEM,S-4800,Hitachi Co.Ltd.,Japan)equipped with energy dispersive X-ray spectroscopy(EDS)and transmission electron microscopy(TEM,2100F,JEOL Co.,Japan).The X-ray photoelectron spectra were obtained by a X-ray photoelectron spectrometry(XPS,ESCALab 250,Thermo VG Co.,USA).The supercapacitor and OER performance of the sample were measured on a CHI 660E electrochemical workstation(Shanghai Chenhua Instrument Co.,China).Results and discussion The as-prepared samples display a cubic perovskite crystalline structure and a hollow sphere morphology.According to the XPS analysis,the variable oxidation states of Cr,Fe and Mn present in the HS-HEPs,which benefits the Faradaic redox reactions and increases the capacitance.In addition,the existence of high concentration of oxygen vacancies in HS-HEPs is beneficial to enhancing the capacitance and OER activity.Based on the GCD curve,the specific capacitance of HS-HEPs is estimated to be 406 F/g at 1 A/g.After GCD cycles of 5000 at a current density of 5 A/g,65%capacitance is retained,implying a good long-term electrochemical stability.An asymmetric supercapacitor device(HS-HEPs//AC)with a two electrode configuration is assembled.A maximum energy density of 39.4 W·h/kg is achieved at power density of 746 W/kg.The OER activity of HS-HEPs is evaluated by a linear sweep voltammetry(LSV)polarization curve in 1 mol/L KOH aqueous solution using a standard three-electrode system.The overpotential of HS-HEPs is identified as 347 mV versus RHE for achieving a current density of 10 mA/cm^(2),which is smaller than that of commercial IrO2(372 mV).The HS-HEPs possess the excellent electrochemical performance,which can be ascribed to the high specific surface area,abundant active sites,and high oxygen vacancy content,resulting from the combination of high-entropy perovskite and special hollow structure.Conclusions High-entropy La(Cr_(0.2)Mn_(0.2)Fe_(0.2)Ni_(0.2)Cu_(0.2))O_(3)hollow spheres with a perovskite crystalline structure were prepared by microwave solvothermal process and subsequent calcination treatment.The HS-HEPs possessed the excellent electrochemical performance,which could be ascribed to the high specific surface area,abundant active sites,and high oxygen vacancy content,resulting from the combination of high-entropy perovskite and special hollow structure.Based on the electrochemical performance,HS-HEPs could be used as supercapacitor electrode material and OER electrocatalysts.This work could provide a strategy to design and prepare high-entropy oxides with a hollow sphere structure,having promising applications in energy storage and conversion.
文摘Filter capacitors play an important role in altern-ating current(AC)-line filtering for stabilizing voltage,sup-pressing harmonics,and improving power quality.However,traditional aluminum electrolytic capacitors(AECs)suffer from a large size,short lifespan,low power density,and poor reliability,which limits their use.In contrast,ultrafast supercapacitors(SCs)are ideal for replacing commercial AECs because of their extremely high power densities,fast charging and discharging,and excellent high-frequency re-sponse.We review the design principles and key parameters for ultrafast supercapacitors and summarize research pro-gress in recent years from the aspects of electrode materials,electrolytes,and device configurations.The preparation,structures,and frequency response performance of electrode materials mainly consisting of carbon materials such as graphene and carbon nanotubes,conductive polymers,and transition metal compounds,are focused on.Finally,future research directions for ultrafast SCs are suggested.
文摘Due to its unique layered structure and excellent electrochemical properties,molybdenum disulfide(MoS_(2))demonstrates significant potential for applications in the energy storage field,particularly in supercapacitors.It is widely regarded as one of the most representative transition metal dichalcogenides.MoS_(2)possesses a high theoretical specific capacitance,abundant edge active sites,and favorable tunability and structural diversity,which provide it with a distinct advantage in the construction of advanced electrode structures.Additionally,the anisotropic characteristics of MoS_(2)concerning electron and ion transport offer more dimensions for regulating its electrochemical behavior.This work will systematically review various synthesis strategies for MoS_(2)and its recent advancements in energy storage,with a particular focus on the mechanisms by which interlayer spacing modulation affects energy storage behavior in supercapacitor configurations.The discussion will encompass a comprehensive logical framework that spans material structure modifications,electronic configuration evolution,and enhancements in macroscopic device performance.This review aims to provide theoretical support and practical guidance for the application of MoS_(2)in the next generation of highperformance energy storage devices.
文摘In order to meet the demands of new-generation electric vehicles that require high power output(over 15 kW/kg),it is crucial to increase the energy density of car-bon-based supercapacitors to a level comparable to that of batteries,while maintaining a high power density.We re-port a porous carbon material produced by immersing pop-lar wood(PW)sawdust in a solution of KOH and graphene oxide(GO),followed by carbonization.The resulting mater-ial has exceptional properties as an electrode for high-en-ergy supercapacitors.Compared to the material prepared by the direct carbonization of PW,its electrical conductivity was in-creased from 0.36 to 26.3 S/cm.Because of this and a high microporosity of over 80%,which provides fast electron channels and a large ion storage surface,when used as the electrodes for a symmetric supercapacitor,it gave a high energy density of 27.9 Wh/kg@0.95 kW/kg in an aqueous electrolyte of 1.0 mol/L Na_(2)SO_(4).The device also had battery-level energy storage with maximum energy densities of 73.9 Wh/kg@2.0 kW/kg and 67.6 Wh/kg@40 kW/kg,an ultrahigh power density,in an organic electrolyte of 1.0 mol/L TEABF4/AN.These values are comparable to those of 30−45 Wh/kg for Pb-acid batteries and 30−55 Wh/kg for aqueous lithium batteries.This work indicates a way to prepare carbon materials that can be used in supercapacit-ors with ultrahigh energy and power densities.
