A new model of porous electrodes based on the Gibbs free energy is developed, in which lithium-ion(Liion) diffusion, diffusion-induced stress(DIS), Butler–Volmer(BV) reaction kinetics, and size polydispersity of elec...A new model of porous electrodes based on the Gibbs free energy is developed, in which lithium-ion(Liion) diffusion, diffusion-induced stress(DIS), Butler–Volmer(BV) reaction kinetics, and size polydispersity of electrode particles are considered. The influence of BV reaction kinetics and concentration-dependent exchange current density(ECD) on concentration profile and DIS evolution are numerically investigated. BV reaction kinetics leads to a decrease in Li-ion concentration and DIS. In addition, concentrationdependent ECD results in a decrease in Li-ion concentration and an increase in DIS. Size polydispersity of electrode particles significantly affects the concentration profile and DIS.Optimal macroscopic state of charge(SOC) should consider the influence of the microscopic SOC values and mass fractions of differently sized particles.展开更多
Sulphur(S)-template method based on conventional slurry-casting method has been developed to pro-duce porous silicon(Si)electrodes.The facile fabrication technology is suitable for current production line and expected...Sulphur(S)-template method based on conventional slurry-casting method has been developed to pro-duce porous silicon(Si)electrodes.The facile fabrication technology is suitable for current production line and expected to be widely applied to various electrode materials under large volume change during operation.Specifically,S particles as template agent are mixed with active material Si,carbon conductor and binder forming uniform slurry.After casting and drying,the electrodes are immersed in carbon disul-fide solution to remove S particles rapidly,generating pores in-situ at the original position of S particles.Electrochemical analysis shows that the pores inside electrodes are able to shorten lithium ion diffusion paths,reduce normal expansion rate and decrease formation of cracks in the Si electrode(2 mg_(Si)/cm^(2)),demonstrating a reversible capacity of 951 mAh/g at 0.5 A/g after 100 cycles(with a capacity retention of 99.5%)and a capacity of-826 mAh/g at 2 A/g.展开更多
Thick electrode,with its feasibility and cost-effectiveness in lithium-ion batteries(LIBs),has attracted significant attention as a promising approach maximizing the energy density of battery.Through raising the mass ...Thick electrode,with its feasibility and cost-effectiveness in lithium-ion batteries(LIBs),has attracted significant attention as a promising approach maximizing the energy density of battery.Through raising the mass loading of active materials without altering the fundamental chemical attributes,thick electrodes can boost the energy density of the batteries effectively.Nevertheless,as the thickness of the electrode increases,the ionic conductivity of the electrode decreases,leading to abominable polarization in the thickness direction,which severely hampers the practical application of a thick electrode.This work proposes a novel porous gradient design of high-performance thick electrodes for LIBs.By constructing a porous structure that serves as a fast transport pathway for lithium(Li)ions,the ion transport kinetics within thick electrodes are significantly enhanced.Meanwhile,a particle size gradient design is incorporated to further mitigate polarization effects within the electrode,leading to substantial improvements in reaction homogeneity and material utilization.Employing this strategy,we have fabricated a porous gradient nanocellulose-carbon-nanotube based thick electrode,which exhibits an impressive capacity retention of 86.7%at a high mass loading of LiCoO_(2)(LCO)active material(20 mg cm^(-2))and a high current density of 5mA cm^(-2).展开更多
The demand for sustainable and stretchable thin-film printed batteries for bioelectronics,wearables,and e-textiles is rapidly increasing.Recently,we developed a fully 3D-printed soft-matter thin-film Ga-Ag_(2)O batter...The demand for sustainable and stretchable thin-film printed batteries for bioelectronics,wearables,and e-textiles is rapidly increasing.Recently,we developed a fully 3D-printed soft-matter thin-film Ga-Ag_(2)O battery with 3R characteristics:resilient to mechanical strain,repairable after damage,and recyclable.This battery achieved a record-breaking areal capacity of 26.37 mAh cm-2,increasing to 30.32 mAh cm^(-2) after 10 cycles under 100%strain.This performance stems from the synergistic effects of gallium’s liquid metal properties and the styrene-isoprene-styrene polymer in the anode.Gallium’s high specific capacity(1153.2 mAh g^(-1)),deformability,and self-healing abilities,supported by its supercooled liquid phase,significantly enhance the battery’s resilience and efficiency.However,the cathode’s lower theoretical capacity,due to Ag_(2)O(231.31 mAh g^(-1)),remains a limitation.Traditional Ag_(2)O-carbon black-styrene-isoprene-styrene cathodes experience rapid capacity decay as only the surface area of the active materials interacts with the electrolyte.To overcome this,we designed a carbon-filled Ag_(2)O foam electrode using a sacrificial sugar template,increasing the effective surface area.This optimization enhanced ion-exchange efficiency,specific capacity,and cyclability,achieving a specific capacity of 221.16 mAh g^(-1).Consequently,the Ga-Ag_(2)O stretchable battery attained a record areal capacity of 40.91 mAh cm^(-2)—double that of nonfoam electrodes—and exhibited fivefold improved charge-discharge cycles.Using ultrastretchable Ag-EGaIn-styrene-isoprene-styrene and carbon black-styrene-isoprene-styrene current collectors,the battery’s specific capacity increased by 33%under 50%strain.Integrated into a soft-matter smart wristband for temperature monitoring,the battery demonstrated its promise for wearable electronics.展开更多
Understanding the mechanisms and properties of various transport processes in the electrolyte,porous electrode,and at the interface between electrode and electrolyte plays a crucial role in guiding the improvement of ...Understanding the mechanisms and properties of various transport processes in the electrolyte,porous electrode,and at the interface between electrode and electrolyte plays a crucial role in guiding the improvement of electrolytes,materials and microstructures of electrode.Nanoscale equilibrium properties and nonequilibrium ion transport are substantially different to that in the bulk,which are difficult to observe from experiments directly.In this paper,we introduce equilibrium and no-equilibrium thermodynamics for electrolyte in porous electrodes or electrolyte-electrode interface.The equilibrium properties of electrical double layer(EDL)including the EDL structure and capacitance are discussed.In addition,classical non-equilibrium thermodynamic theory is introduced to help us understand the coupling effect of different transport processes.We also review the recent studies of nonequilibrium ion transport in porous electrode by molecular and continuum methods,among these methods,dynamic density functional theory(DDFT)shows tremendous potential as its high efficiency and high accuracy.Moreover,some opportunities for future development and application of the non-equilibrium thermodynamics in electrochemical system are prospected.展开更多
Thermocells are garnering increasing attention as a promising thermoelectric technology for harvesting low-grade heat.However,their performance is often limited by the scarcity of high-performance redox couples that p...Thermocells are garnering increasing attention as a promising thermoelectric technology for harvesting low-grade heat.However,their performance is often limited by the scarcity of high-performance redox couples that possess both high thermopower and rapid redox kinetics.This work addresses this challenge by leveraging our recently developed copper(Ⅰ/Ⅱ)(Cu^(+)/Cu^(2+))redox couple.We significantly enhance the performance of Cu-based liquid thermocells by integrating a thermosensitive crystallization process with etched carbon cloth electrodes,achieving synergistic improvements in thermodynamic and kinetic performance.The thermosensitive crystallization process establishes a persistent Cu^(2+)concentration gradient,boosting the thermopower from 1.47 to 2.93 mV K^(-1).Moreover,the etched carbon cloth electrodes provide a larger electroactive surface area and demonstrate a higher current density.Consequently,the optimized Cu^(+)/Cu^(2+)system achieved an exceptional normalized power density P_(max)(ΔT)^(-2)of 3.97 mW m^(-2)K^(-2).A thermocell module comprised of 20 cells directly power various electronic devices at a temperature difference of 40 K.This work successfully exhibits potential of Cu^(+)/Cu^(2+)redox couple in thermoelectric conversion and introduces a valuable redox couple for highperformance thermocells.展开更多
A novel type of porous magnesium electrode with a stable 3D copper foam as current collectors for the organic magnesium-air battery was prepared by both amperostatic and pulsed electrodeposition of magnesium on copper...A novel type of porous magnesium electrode with a stable 3D copper foam as current collectors for the organic magnesium-air battery was prepared by both amperostatic and pulsed electrodeposition of magnesium on copper foam substrates in an electrolyte of 1 mol/L EtMgBr/THF solution, respectively. Optimal parameters of the pulsed electrodeposition were obtained using a bending cathode at the right angle. The surface morphology of the porous electrode was investigated by SEM, and the discharging performance of the porous magnesium electrode was detected by the chronoamperometric measurement. The electrochemical stability of 3D copper foam current collectors was examined by cyclic voltammetry, SEM and ICP-OES analyses. The results show that the rate capability of the porous magnesium electrode with a stable 3D copper foam as a current collector is better than that of the planar magnesium electrode, and the rate capability of the porous magnesium electrode prepared by the pulsed electrodeposition is superior to that of the porous magnesium electrode prepared by the amperostatic electrodeposition. The 3D structure of copper foam current collectors of the porous magnesium electrode could keep stable during the discharging process.展开更多
In order to obtain a porous Mg electrode with a stable skeleton, organic Mg fuel cell （OMFC）, the electrochemical behavior of Mg deposition on Cu and Ni metallic substrates in 1 mol/L EtMgBr/THF solution was investi...In order to obtain a porous Mg electrode with a stable skeleton, organic Mg fuel cell （OMFC）, the electrochemical behavior of Mg deposition on Cu and Ni metallic substrates in 1 mol/L EtMgBr/THF solution was investigated by SEM, EDS and electrochemical methods. The experimental results show that Mg can be electrodeposited on both substrates, as a continuous layer on a Cu substrate. Accordingly, an approach for producing a porous Mg electrode with a stable skeleton of OMFC was proposed by means of electrodeposition of Mg on a foamed Ni substrate with a layer of Cu pre-plating. The discharge performance of this porous Mg electrode of OMFC is superior to that of a planar Mg electrode.展开更多
The polyaniline/polysulfone（PAN/PSF） composite films were prepared by electropolymerization,and then CeO2-Pt particles were codeposited into this composite film to obtain the CeO2-Pt-modified polyaniline/polysulfone...The polyaniline/polysulfone（PAN/PSF） composite films were prepared by electropolymerization,and then CeO2-Pt particles were codeposited into this composite film to obtain the CeO2-Pt-modified polyaniline/polysulfone（CeO2-Pt/PAN/PSF） electrodes.Their morphol-ogy and chemical component were characterized by field emission scanning electron microscopy（FESEM） and energy dispersive X-ray spectroscopy（EDS）,respectively.The results showed that the composite film had bi-layer structure with asymmetrical pores,and platinum and cerium oxide particles were homogeneously dispersed in the modified film electrodes.The cyclic voltammetry（CV） and electrochemical impedance spectroscopy（EIS） techniques were applied to investigate the electrocatalytic activity of the Pt-CeO2/PAN/PSF electrodes.It was indicated that appropriate amount of CeO2 could enhance the catalytic activity of Pt for methanol electro-oxidation.Chronoamperometry（i-t） measurements revealed that the Pt-CeO2/PAN/PSF electrode was relatively endurable for intermediate production.In addition,different mix-ing amounts of Pt and CeO2 nanoparticles were also investigated in detail.展开更多
Rate capability,peak power,and energy density are of vital importance for the capacitive energy storage(CES)of electrochemical energy devices.The frequency response analysis(FRA)is regarded as an efficient tool in stu...Rate capability,peak power,and energy density are of vital importance for the capacitive energy storage(CES)of electrochemical energy devices.The frequency response analysis(FRA)is regarded as an efficient tool in studying the CES.In the present work,a bi-scale impedance transmission line model(TLM)is firstly developed for a single pore to a porous electrode.Not only the TLM of the single pore is reparameterized but also the particle packing compactness is defined in the bi-scale.Subsequently,the CES properties are identified by FRA,focused on rate capability vs.characteristic frequency,peak power vs.equivalent series resistance,and energy density vs.low frequency limiting capacitance for a single pore to a porous electrode.Based on these relationships,the CES properties are numerically simulated and theoretically predicted for a single pore to a porous electrode in terms of intra-particle pore length,intra-particle pore diameter,inter-particle pore diameter,electrolyte conductivity,interfacial capacitance&exponent factor,electrode thickness,electrode apparent surface area,and particle packing compactness.Finally,the experimental diagnosis of four supercapacitors(SCs)with different electrode thicknesses is conducted for validating the bi-scale TLM and gaining an insight into the CES properties for a porous electrode to a single pore.The calculating results suggest,to some extent,the inter-particle pore plays a more critical role than the intra-particle pore in the CES properties such as the rate capability and the peak power density for a single pore to a porous electrode.Hence,in order to design a better porous electrode,more attention should be given to the inter-particle pore.展开更多
Porous platinum electrodes were prepared by adding YSZ,as an active material,in platinum paste.Relationship between microstructure and electrochemical performance of O 2(g),Pt/YSZ electrode have been characterized by ...Porous platinum electrodes were prepared by adding YSZ,as an active material,in platinum paste.Relationship between microstructure and electrochemical performance of O 2(g),Pt/YSZ electrode have been characterized by SEM and cyclic voltammetry.Results showed that the microstructure of platinum electrode is a significant impact on the cyclic voltammetry.With the increase of platinum electrode's porosity,the area of three-phase boundary of O 2(g) /Pt/YSZ was increased.The electrochemical reactivity was also enhanced.These were presented as the increase of current density and cathode voltage in cyclic voltammetry.展开更多
The development of a simple, efficient and sensitive sensor for dissolved oxygen is proposed using a novel type of porous carbon composite membrane/glassy carbon electrode based on the low-cost common filter paper by ...The development of a simple, efficient and sensitive sensor for dissolved oxygen is proposed using a novel type of porous carbon composite membrane/glassy carbon electrode based on the low-cost common filter paper by a simple method. The resulting device exhibited excellent electrocatalytic activities toward the oxygen reduction reaction. Scanning electron microscopy, transmission electron microscopy, X-ray photoelectron spectroscopy and electrochemical measurements demonstrated that the porous morphology and uniformly dispersed Fe;C nanoparticles of the PCCM play an important role in the oxygen reduction reaction. A linear response range from 2mmol/L up to 110 mmol/L and a detection limit of 1.4 mmol/L was obtained with this sensor. The repeatability of the proposed sensor,evaluated in terms of relative standard deviation, was 3.0%. The successful fabrication of PCCM/GC electrode may promote the development of new porous carbon oxygen reduction reaction material for the oxygen reduction sensor.展开更多
Anodic oxidation electrodeposition is the primary way to prepare lead dioxide anode. The regulation of the external circuit for the reaction is a unique advantage of electrocatalytic reaction, which can regulate cryst...Anodic oxidation electrodeposition is the primary way to prepare lead dioxide anode. The regulation of the external circuit for the reaction is a unique advantage of electrocatalytic reaction, which can regulate crystallization and accelerate the reaction process. In this study, lead dioxide coatings with uniform pore size distribution were quickly prepared on three different substrates by potential linear increase electrodeposition(PLIED). Morphology and structure analysis shows that the prepared electrodes have uniform porous morphology, and Ti/SnO_(2)/PLIED has the smallest grain size. Three electrodes all display well degradation performance to azophloxine and diclofenac sodium. Ti/PLIED, and Ti/SnO_(2)/PLIED are appreciated for degrading organics with a simple structure in low concentrations. At the same time,Ti/SnO_(2)/PLIED is more suitable for complex organics in high concentrations. Electrochemical activity tests indicate the different mechanisms of the PLIED electrodes that build the other degradation performance.Three PLIED electrodes show excellent electrical and electrochemical stability during the cycle degradation process. The results provide a reference for the subsequent anodic oxidation electrodeposition research and the regulating effect of the external circuit on coating properties.展开更多
The bio-nanotechnological fabrication of high-surface-area carbons has attracted widespread interest in supercapacitor applications by using readily-available natural products as raw materials or bio-templates,and is ...The bio-nanotechnological fabrication of high-surface-area carbons has attracted widespread interest in supercapacitor applications by using readily-available natural products as raw materials or bio-templates,and is expected to refine on pore accessibility for compact energy storage. Here, a renovated design strategy of semi-biomass interpenetrating polymer network(IPN) derived carbon is demonstrated through physically knitting the biomacromolecule(sodium alginate, SA) polymeric chains into the highly crosslinked resorcinol-formaldehyde(RF) network and subsequent thermochemical conversion. Moleculelevel interlacing forces in such IPN efficiently relieve the RF skeleton shrinkage when producing carbon,while the other SA network addresses the macrophase separation issue to sacrifice as an in-knitted porogen and a morphology-directing agent. As a result, porous carbon globules are equipped with moss-like surfaces and interconnected pore architecture for high accessible electrode surface(1013 m^(2)/g), and efficient electrochemical responses are reached with the specific capacitance of 312 F/g at 1 A/g. Taking the advantage of 9 mol/kg NaClO_(4) complex-solvent electrolyte, the voltage window is extended to 2.4 V,endowing the two-electrode device with the high energy delivery of 32.3 Wh/kg at 240 W/kg.展开更多
Solid oxide cells(SOCs),capable of interconverting electrical and chemical energy,have emerged as one of the key technologies for the future multi-energy complementary grid.However,the commercialization of SOCs is hin...Solid oxide cells(SOCs),capable of interconverting electrical and chemical energy,have emerged as one of the key technologies for the future multi-energy complementary grid.However,the commercialization of SOCs is hindered by poor long-term stability,attributed in large part to the microstructural evolution of the electrodes,which results in the loss of active reaction sites,blockage of gas transport pathways,and degradation of mechanical properties.Owing to recently developed three-dimensional(3D)microstructure reconstruction techniques,the microstructural evolution of SOC electrodes can now be investigated quantitatively.This review highlights insights gained from studies of the microstructural evolution of porous cermet SOC electrodes during long-term operation and redox cycling,and the corresponding effects on electrochemical and mechanical performance,with particular attention to investigations using 3D reconstruction technologies.The influencing parameters and the possible strategies to mitigate microstructure evolution-induced degradation are also summarized.The challenges and opportunities for the future development of stable and active SOC electrode microstructures are analyzed,and the corresponding prospects for commercial application are provided.展开更多
Liquid phosphoric acid(PA),as the proton carrier for high temperature polymer electrolyte membrane fuel cells(HT-PEMFCs),presents challenges such as catalyst poisoning,high gas transport resistance and electrolyte los...Liquid phosphoric acid(PA),as the proton carrier for high temperature polymer electrolyte membrane fuel cells(HT-PEMFCs),presents challenges such as catalyst poisoning,high gas transport resistance and electrolyte loss.These issues significantly impede the performance and durability of HT-PEMFCs,thereby limiting their potential for further application.In this study,poly(2,3,5,6-tetrafluorostylene-4-phosphonic acid)(PWN)with intrinsic proton conduction ability was employed as catalyst layer binder to reveal the impacts of the ionomer's molecular structure on mass transport within the catalyst layer.Our findings demonstrated that increasing the phosphorylation degree of PWN could enhance both pore formation at the catalyst layer and electrode acidophilic capability while improving proton conduction ability and reducing cells'internal resistance.However,adverse effects included increased local oxygen transport resistance and decreased catalyst utilization resulting from electrode acidophilic capability.This research offers valuable insights for the relationships between micro-scale molecule structure,mesoscale electrode architecture,and membrane electrode assembly design in HT-PEMFCs.展开更多
High-performance solid polymer electrolyte （SPE） has long been desired for the next-generation high energy density and safe rechargeable lithium batteries. A SPE composed of 80 wt% lithium bis（trifluo-romethanesulf...High-performance solid polymer electrolyte （SPE） has long been desired for the next-generation high energy density and safe rechargeable lithium batteries. A SPE composed of 80 wt% lithium bis（trifluo-romethanesulfonyl）imide （LiTFSI）, 20% poly（ethylene carbonate） （PEC） and a polyamide （PA） fiber membrane backbone was prepared by solution-casting method. This solid electrolyte exhibits quite high ionic conductivity and lithium ion transference number （t＋）, and excellent mechanical strength. The as-prepared solid electrolyte shows good wettability to porous electrodes during cycles, which is beneficial to form ionically conductive phase throughout porous electrodes. All-solid-state LiFePO4lLi cells assembled with the as-prepared solid electrolyte deliver a high initial discharge specific capacity of 125.7 mAh·g^-1 and good cycling stability at 55 ℃ （93.4% retention at 1C after 200 cycles）, and superior cycle performance. Outstanding electrochemical performance can be mainly ascribed to the improved ionic conductivity in the entire porous electrodes due to the good wettability of SPE.展开更多
Alkaline water electrolysis is a practical route for large-scale green hydrogen production to assist decarbonization,whereby carbon dioxide emissions are limited.However,the use of this process in hydrogen evolution r...Alkaline water electrolysis is a practical route for large-scale green hydrogen production to assist decarbonization,whereby carbon dioxide emissions are limited.However,the use of this process in hydrogen evolution reaction(HER)is hampered by the alkaline solution,which leads to slow H_(2)O dissociation kinetics,especially when nickel–molybdenum(NiMo)alloy catalysts are utilized;thus,an improvement of this approach for effective HER activity is desirable.In this work,a porous phosphide NiMo-based(NiMoP)alloy electrode catalyst was engineered using a multistep electrodeposition method.Various experiments,combined with theoretical calculations,confirmed that the phosphide incorporation in the NiMo alloys promoted alkaline HER performance at a high current density of 1000 mA cm^(−2)with the potential−0.191 V.The evaluation of the effect of electrodeposition current density on HER performance revealed that the P content indeed positively impacted the accompanying alkaline HER performance,attributable to phosphide contribution in the electron reconstruction.Density functional theory(DFT)calculations demonstrated that the P atom promoted the loss of Mo electrons and hindered Ni from gaining electrons.This charge reconstruction allowed the optimization of the H^(*)adsorption,contributing to a stronger H_(2)O adsorption and encouraging H-OH^(*)bond breakage.Our current approach may provide the possibility of designing high-performance alkaline HER electrodes at high current density.展开更多
Graphite material was used as the electrode for an all-vanadium redox flow battery, and the electrode was modified by transition metallic ions to enhance its electrochemical behavior. An porous graphite composite elec...Graphite material was used as the electrode for an all-vanadium redox flow battery, and the electrode was modified by transition metallic ions to enhance its electrochemical behavior. An porous graphite composite electrode has high specific surface area and high current density. The electrode modified by transition metallic ions has improved catalysis behavior that can catalyze the V（Ⅱ）-V（Ⅴ） redox reaction showed by cyclic voltammograms. This article studied the impedance of the modified electrode by electrochemical impedance spectroscopy （EIS）, and approved that the electrode modified by Co^2＋ and Mn^2＋ has a lower charge transfer resistance than the non-modified electrode. The effect of average particle size distribution is at lower frequencies that the slope of Warburg impedance is reduced by large particle size distribution. The voltage efficiency of the Co^2＋ modified electrode test cell is 81.5%, which is higher than that of the non-modified electrode.展开更多
Three-dimensional(3D)grid porous electrodes introduce vertically aligned pores as a convenient path for the transport of lithium-ions(Li-ions),thereby reducing the total transport distance of Li-ions and improving the...Three-dimensional(3D)grid porous electrodes introduce vertically aligned pores as a convenient path for the transport of lithium-ions(Li-ions),thereby reducing the total transport distance of Li-ions and improving the reaction kinetics.Although there have been other studies focusing on 3D electrodes fabricated by 3D printing,there still exists a gap between electrode design and their electrochemical performance.In this study,we try to bridge this gap through a comprehensive investigation on the effects of various electrode parameters including the electrode porosity,active material particle diameter,electrode electronic conductivity,electrode thickness,line width,and pore size on the electrochemical performance.Both numerical simulations and experimental investigations are conducted to systematically examine these effects.3D grid porous Li_(4)Ti_(5)O_(12)(LTO)thick electrodes are fabricated by low temperature direct writing technology and the electrodes with the thickness of 1085μm and areal mass loading of 39.44 mg·cm^(−2) are obtained.The electrodes display impressive electrochemical performance with the areal capacity of 5.88 mAh·cm^(−2)@1.0 C,areal energy density of 28.95 J·cm^(−2)@1.0 C,and areal power density of 8.04 mW·cm^(−2)@1.0 C.This study can provide design guidelines for obtaining 3D grid porous electrodes with superior electrochemical performance.展开更多
基金financial support by the National Natural Science Foundation of China (Grants 11472165, 11332005)
文摘A new model of porous electrodes based on the Gibbs free energy is developed, in which lithium-ion(Liion) diffusion, diffusion-induced stress(DIS), Butler–Volmer(BV) reaction kinetics, and size polydispersity of electrode particles are considered. The influence of BV reaction kinetics and concentration-dependent exchange current density(ECD) on concentration profile and DIS evolution are numerically investigated. BV reaction kinetics leads to a decrease in Li-ion concentration and DIS. In addition, concentrationdependent ECD results in a decrease in Li-ion concentration and an increase in DIS. Size polydispersity of electrode particles significantly affects the concentration profile and DIS.Optimal macroscopic state of charge(SOC) should consider the influence of the microscopic SOC values and mass fractions of differently sized particles.
基金the National Natural Science Foundation of China(Nos.51904344,52172264)the Natural Science Foundation of Hunan Province of China(Nos.2021JJ10060,2022GK2033).
文摘Sulphur(S)-template method based on conventional slurry-casting method has been developed to pro-duce porous silicon(Si)electrodes.The facile fabrication technology is suitable for current production line and expected to be widely applied to various electrode materials under large volume change during operation.Specifically,S particles as template agent are mixed with active material Si,carbon conductor and binder forming uniform slurry.After casting and drying,the electrodes are immersed in carbon disul-fide solution to remove S particles rapidly,generating pores in-situ at the original position of S particles.Electrochemical analysis shows that the pores inside electrodes are able to shorten lithium ion diffusion paths,reduce normal expansion rate and decrease formation of cracks in the Si electrode(2 mg_(Si)/cm^(2)),demonstrating a reversible capacity of 951 mAh/g at 0.5 A/g after 100 cycles(with a capacity retention of 99.5%)and a capacity of-826 mAh/g at 2 A/g.
基金financially supported by the National Key R&D Program of China(2023YFB2503900)the National Natural Science Foundation of China(U22A20140,52072138)the Shenzhen Science and Technology Program(JCYJ20220818100418040,JCYJ20220530160816038)。
文摘Thick electrode,with its feasibility and cost-effectiveness in lithium-ion batteries(LIBs),has attracted significant attention as a promising approach maximizing the energy density of battery.Through raising the mass loading of active materials without altering the fundamental chemical attributes,thick electrodes can boost the energy density of the batteries effectively.Nevertheless,as the thickness of the electrode increases,the ionic conductivity of the electrode decreases,leading to abominable polarization in the thickness direction,which severely hampers the practical application of a thick electrode.This work proposes a novel porous gradient design of high-performance thick electrodes for LIBs.By constructing a porous structure that serves as a fast transport pathway for lithium(Li)ions,the ion transport kinetics within thick electrodes are significantly enhanced.Meanwhile,a particle size gradient design is incorporated to further mitigate polarization effects within the electrode,leading to substantial improvements in reaction homogeneity and material utilization.Employing this strategy,we have fabricated a porous gradient nanocellulose-carbon-nanotube based thick electrode,which exhibits an impressive capacity retention of 86.7%at a high mass loading of LiCoO_(2)(LCO)active material(20 mg cm^(-2))and a high current density of 5mA cm^(-2).
基金supported by the European Research Council,ERC project Liquid3D,grant number 101045072supported by the Foundation of Science and Technology(FCT)of Portugal through the CMU-Portugal project WoW(Reference No:45913).
文摘The demand for sustainable and stretchable thin-film printed batteries for bioelectronics,wearables,and e-textiles is rapidly increasing.Recently,we developed a fully 3D-printed soft-matter thin-film Ga-Ag_(2)O battery with 3R characteristics:resilient to mechanical strain,repairable after damage,and recyclable.This battery achieved a record-breaking areal capacity of 26.37 mAh cm-2,increasing to 30.32 mAh cm^(-2) after 10 cycles under 100%strain.This performance stems from the synergistic effects of gallium’s liquid metal properties and the styrene-isoprene-styrene polymer in the anode.Gallium’s high specific capacity(1153.2 mAh g^(-1)),deformability,and self-healing abilities,supported by its supercooled liquid phase,significantly enhance the battery’s resilience and efficiency.However,the cathode’s lower theoretical capacity,due to Ag_(2)O(231.31 mAh g^(-1)),remains a limitation.Traditional Ag_(2)O-carbon black-styrene-isoprene-styrene cathodes experience rapid capacity decay as only the surface area of the active materials interacts with the electrolyte.To overcome this,we designed a carbon-filled Ag_(2)O foam electrode using a sacrificial sugar template,increasing the effective surface area.This optimization enhanced ion-exchange efficiency,specific capacity,and cyclability,achieving a specific capacity of 221.16 mAh g^(-1).Consequently,the Ga-Ag_(2)O stretchable battery attained a record areal capacity of 40.91 mAh cm^(-2)—double that of nonfoam electrodes—and exhibited fivefold improved charge-discharge cycles.Using ultrastretchable Ag-EGaIn-styrene-isoprene-styrene and carbon black-styrene-isoprene-styrene current collectors,the battery’s specific capacity increased by 33%under 50%strain.Integrated into a soft-matter smart wristband for temperature monitoring,the battery demonstrated its promise for wearable electronics.
基金sponsored by the National Natural Science Foundation of China(No.91834301,21808055)National Natural Science Foundation of China for Innovative Research Groups(No.)+1 种基金the Shanghai Sailing Program(18YF1405400)EU-FET project NANOPHLOW0(REP-766972-1)。
文摘Understanding the mechanisms and properties of various transport processes in the electrolyte,porous electrode,and at the interface between electrode and electrolyte plays a crucial role in guiding the improvement of electrolytes,materials and microstructures of electrode.Nanoscale equilibrium properties and nonequilibrium ion transport are substantially different to that in the bulk,which are difficult to observe from experiments directly.In this paper,we introduce equilibrium and no-equilibrium thermodynamics for electrolyte in porous electrodes or electrolyte-electrode interface.The equilibrium properties of electrical double layer(EDL)including the EDL structure and capacitance are discussed.In addition,classical non-equilibrium thermodynamic theory is introduced to help us understand the coupling effect of different transport processes.We also review the recent studies of nonequilibrium ion transport in porous electrode by molecular and continuum methods,among these methods,dynamic density functional theory(DDFT)shows tremendous potential as its high efficiency and high accuracy.Moreover,some opportunities for future development and application of the non-equilibrium thermodynamics in electrochemical system are prospected.
基金financially supported by research grants from Innovative Research Group Project of National Natural Science Foundation of China(52021004)the National Key Research and Development Program of China(2022YFB3803300)+1 种基金the National Natural Science Foundation of China(62474026,62205140,12204071)the China Postdoctoral Science Foundation(2022M710532)。
文摘Thermocells are garnering increasing attention as a promising thermoelectric technology for harvesting low-grade heat.However,their performance is often limited by the scarcity of high-performance redox couples that possess both high thermopower and rapid redox kinetics.This work addresses this challenge by leveraging our recently developed copper(Ⅰ/Ⅱ)(Cu^(+)/Cu^(2+))redox couple.We significantly enhance the performance of Cu-based liquid thermocells by integrating a thermosensitive crystallization process with etched carbon cloth electrodes,achieving synergistic improvements in thermodynamic and kinetic performance.The thermosensitive crystallization process establishes a persistent Cu^(2+)concentration gradient,boosting the thermopower from 1.47 to 2.93 mV K^(-1).Moreover,the etched carbon cloth electrodes provide a larger electroactive surface area and demonstrate a higher current density.Consequently,the optimized Cu^(+)/Cu^(2+)system achieved an exceptional normalized power density P_(max)(ΔT)^(-2)of 3.97 mW m^(-2)K^(-2).A thermocell module comprised of 20 cells directly power various electronic devices at a temperature difference of 40 K.This work successfully exhibits potential of Cu^(+)/Cu^(2+)redox couple in thermoelectric conversion and introduces a valuable redox couple for highperformance thermocells.
基金Project(20973124)supported by the National Natural Science Foundation of ChinaProject supported by Key Laboratory of Superlight Materials and Surface Technology,Ministry of Education(Harbin Engineering University),China
文摘A novel type of porous magnesium electrode with a stable 3D copper foam as current collectors for the organic magnesium-air battery was prepared by both amperostatic and pulsed electrodeposition of magnesium on copper foam substrates in an electrolyte of 1 mol/L EtMgBr/THF solution, respectively. Optimal parameters of the pulsed electrodeposition were obtained using a bending cathode at the right angle. The surface morphology of the porous electrode was investigated by SEM, and the discharging performance of the porous magnesium electrode was detected by the chronoamperometric measurement. The electrochemical stability of 3D copper foam current collectors was examined by cyclic voltammetry, SEM and ICP-OES analyses. The results show that the rate capability of the porous magnesium electrode with a stable 3D copper foam as a current collector is better than that of the planar magnesium electrode, and the rate capability of the porous magnesium electrode prepared by the pulsed electrodeposition is superior to that of the porous magnesium electrode prepared by the amperostatic electrodeposition. The 3D structure of copper foam current collectors of the porous magnesium electrode could keep stable during the discharging process.
基金Project(20973124)supported by the National Natural Science Foundation of China
文摘In order to obtain a porous Mg electrode with a stable skeleton, organic Mg fuel cell （OMFC）, the electrochemical behavior of Mg deposition on Cu and Ni metallic substrates in 1 mol/L EtMgBr/THF solution was investigated by SEM, EDS and electrochemical methods. The experimental results show that Mg can be electrodeposited on both substrates, as a continuous layer on a Cu substrate. Accordingly, an approach for producing a porous Mg electrode with a stable skeleton of OMFC was proposed by means of electrodeposition of Mg on a foamed Ni substrate with a layer of Cu pre-plating. The discharge performance of this porous Mg electrode of OMFC is superior to that of a planar Mg electrode.
基金Project supported by the National Natural Science Foundation of China (20475077)
文摘The polyaniline/polysulfone（PAN/PSF） composite films were prepared by electropolymerization,and then CeO2-Pt particles were codeposited into this composite film to obtain the CeO2-Pt-modified polyaniline/polysulfone（CeO2-Pt/PAN/PSF） electrodes.Their morphol-ogy and chemical component were characterized by field emission scanning electron microscopy（FESEM） and energy dispersive X-ray spectroscopy（EDS）,respectively.The results showed that the composite film had bi-layer structure with asymmetrical pores,and platinum and cerium oxide particles were homogeneously dispersed in the modified film electrodes.The cyclic voltammetry（CV） and electrochemical impedance spectroscopy（EIS） techniques were applied to investigate the electrocatalytic activity of the Pt-CeO2/PAN/PSF electrodes.It was indicated that appropriate amount of CeO2 could enhance the catalytic activity of Pt for methanol electro-oxidation.Chronoamperometry（i-t） measurements revealed that the Pt-CeO2/PAN/PSF electrode was relatively endurable for intermediate production.In addition,different mix-ing amounts of Pt and CeO2 nanoparticles were also investigated in detail.
基金financial support from the National Science Foundation of China(22078190)the National Key R&D Plan of China(2020YFB1505802)。
文摘Rate capability,peak power,and energy density are of vital importance for the capacitive energy storage(CES)of electrochemical energy devices.The frequency response analysis(FRA)is regarded as an efficient tool in studying the CES.In the present work,a bi-scale impedance transmission line model(TLM)is firstly developed for a single pore to a porous electrode.Not only the TLM of the single pore is reparameterized but also the particle packing compactness is defined in the bi-scale.Subsequently,the CES properties are identified by FRA,focused on rate capability vs.characteristic frequency,peak power vs.equivalent series resistance,and energy density vs.low frequency limiting capacitance for a single pore to a porous electrode.Based on these relationships,the CES properties are numerically simulated and theoretically predicted for a single pore to a porous electrode in terms of intra-particle pore length,intra-particle pore diameter,inter-particle pore diameter,electrolyte conductivity,interfacial capacitance&exponent factor,electrode thickness,electrode apparent surface area,and particle packing compactness.Finally,the experimental diagnosis of four supercapacitors(SCs)with different electrode thicknesses is conducted for validating the bi-scale TLM and gaining an insight into the CES properties for a porous electrode to a single pore.The calculating results suggest,to some extent,the inter-particle pore plays a more critical role than the intra-particle pore in the CES properties such as the rate capability and the peak power density for a single pore to a porous electrode.Hence,in order to design a better porous electrode,more attention should be given to the inter-particle pore.
文摘Porous platinum electrodes were prepared by adding YSZ,as an active material,in platinum paste.Relationship between microstructure and electrochemical performance of O 2(g),Pt/YSZ electrode have been characterized by SEM and cyclic voltammetry.Results showed that the microstructure of platinum electrode is a significant impact on the cyclic voltammetry.With the increase of platinum electrode's porosity,the area of three-phase boundary of O 2(g) /Pt/YSZ was increased.The electrochemical reactivity was also enhanced.These were presented as the increase of current density and cathode voltage in cyclic voltammetry.
基金the National Natural Science Foundation of China (No.21273097)the project from the State Key Laboratory of Electroanalytical Chemistry (No.2013)the Science Foundation of Jilin Province (No.20130204003GX)
文摘The development of a simple, efficient and sensitive sensor for dissolved oxygen is proposed using a novel type of porous carbon composite membrane/glassy carbon electrode based on the low-cost common filter paper by a simple method. The resulting device exhibited excellent electrocatalytic activities toward the oxygen reduction reaction. Scanning electron microscopy, transmission electron microscopy, X-ray photoelectron spectroscopy and electrochemical measurements demonstrated that the porous morphology and uniformly dispersed Fe;C nanoparticles of the PCCM play an important role in the oxygen reduction reaction. A linear response range from 2mmol/L up to 110 mmol/L and a detection limit of 1.4 mmol/L was obtained with this sensor. The repeatability of the proposed sensor,evaluated in terms of relative standard deviation, was 3.0%. The successful fabrication of PCCM/GC electrode may promote the development of new porous carbon oxygen reduction reaction material for the oxygen reduction sensor.
基金the financial supports from the National Natural Science Foundation of China (No. 52270078)the Natural Science Basic Research Plan in Shaanxi Province of China (No. 2021JM-012)+1 种基金the Welfare Technology Research Plan of Zhejiang Province (No. LZY21E080003)the Fundamental Research Funds for the Central Universities (No. xjh012020037)。
文摘Anodic oxidation electrodeposition is the primary way to prepare lead dioxide anode. The regulation of the external circuit for the reaction is a unique advantage of electrocatalytic reaction, which can regulate crystallization and accelerate the reaction process. In this study, lead dioxide coatings with uniform pore size distribution were quickly prepared on three different substrates by potential linear increase electrodeposition(PLIED). Morphology and structure analysis shows that the prepared electrodes have uniform porous morphology, and Ti/SnO_(2)/PLIED has the smallest grain size. Three electrodes all display well degradation performance to azophloxine and diclofenac sodium. Ti/PLIED, and Ti/SnO_(2)/PLIED are appreciated for degrading organics with a simple structure in low concentrations. At the same time,Ti/SnO_(2)/PLIED is more suitable for complex organics in high concentrations. Electrochemical activity tests indicate the different mechanisms of the PLIED electrodes that build the other degradation performance.Three PLIED electrodes show excellent electrical and electrochemical stability during the cycle degradation process. The results provide a reference for the subsequent anodic oxidation electrodeposition research and the regulating effect of the external circuit on coating properties.
基金financially supported by the National Natural Science Foundation of China (Nos. 51772216, 21905207, 21875165 and 21703161)the Science and Technology Commission of Shanghai Municipality, China (Nos. 20ZR1460300, 14DZ2261100)+2 种基金Zhejiang Provincial Natural Science Foundation of China (No. LY19B010003)the Fundamental Research Funds for the Central Universitiesthe Large Equipment Test Foundation of Tongji University。
文摘The bio-nanotechnological fabrication of high-surface-area carbons has attracted widespread interest in supercapacitor applications by using readily-available natural products as raw materials or bio-templates,and is expected to refine on pore accessibility for compact energy storage. Here, a renovated design strategy of semi-biomass interpenetrating polymer network(IPN) derived carbon is demonstrated through physically knitting the biomacromolecule(sodium alginate, SA) polymeric chains into the highly crosslinked resorcinol-formaldehyde(RF) network and subsequent thermochemical conversion. Moleculelevel interlacing forces in such IPN efficiently relieve the RF skeleton shrinkage when producing carbon,while the other SA network addresses the macrophase separation issue to sacrifice as an in-knitted porogen and a morphology-directing agent. As a result, porous carbon globules are equipped with moss-like surfaces and interconnected pore architecture for high accessible electrode surface(1013 m^(2)/g), and efficient electrochemical responses are reached with the specific capacitance of 312 F/g at 1 A/g. Taking the advantage of 9 mol/kg NaClO_(4) complex-solvent electrolyte, the voltage window is extended to 2.4 V,endowing the two-electrode device with the high energy delivery of 32.3 Wh/kg at 240 W/kg.
基金funding from National Natural Science Foundation of China,China(52102226,12472173)Guangdong Basic and Applied Basic Research Foundation,China(2023A1515011003,2023A1515010723)+2 种基金Science,Technology and Innovation Commission of Shenzhen Municipality,China(GJHZ20220913143009017,GJHZ20210705141401004)the Talent Recruitment Project of Guangdong Province,China(2019QN01G098)Development and Reform Commission of Shenzhen Municipality,China(XMHT20220103004).
文摘Solid oxide cells(SOCs),capable of interconverting electrical and chemical energy,have emerged as one of the key technologies for the future multi-energy complementary grid.However,the commercialization of SOCs is hindered by poor long-term stability,attributed in large part to the microstructural evolution of the electrodes,which results in the loss of active reaction sites,blockage of gas transport pathways,and degradation of mechanical properties.Owing to recently developed three-dimensional(3D)microstructure reconstruction techniques,the microstructural evolution of SOC electrodes can now be investigated quantitatively.This review highlights insights gained from studies of the microstructural evolution of porous cermet SOC electrodes during long-term operation and redox cycling,and the corresponding effects on electrochemical and mechanical performance,with particular attention to investigations using 3D reconstruction technologies.The influencing parameters and the possible strategies to mitigate microstructure evolution-induced degradation are also summarized.The challenges and opportunities for the future development of stable and active SOC electrode microstructures are analyzed,and the corresponding prospects for commercial application are provided.
基金supported by The National Key Research and Development Program of China(2021YFB4001204)National Natural Science Foundation of China(22179130,22379143,22479145)。
文摘Liquid phosphoric acid(PA),as the proton carrier for high temperature polymer electrolyte membrane fuel cells(HT-PEMFCs),presents challenges such as catalyst poisoning,high gas transport resistance and electrolyte loss.These issues significantly impede the performance and durability of HT-PEMFCs,thereby limiting their potential for further application.In this study,poly(2,3,5,6-tetrafluorostylene-4-phosphonic acid)(PWN)with intrinsic proton conduction ability was employed as catalyst layer binder to reveal the impacts of the ionomer's molecular structure on mass transport within the catalyst layer.Our findings demonstrated that increasing the phosphorylation degree of PWN could enhance both pore formation at the catalyst layer and electrode acidophilic capability while improving proton conduction ability and reducing cells'internal resistance.However,adverse effects included increased local oxygen transport resistance and decreased catalyst utilization resulting from electrode acidophilic capability.This research offers valuable insights for the relationships between micro-scale molecule structure,mesoscale electrode architecture,and membrane electrode assembly design in HT-PEMFCs.
基金financially supported by the National Natural Scientific Foundation of China(No.51532002)Beijing Natural Science Foundation(No.L172023)the National Basic Research Program of China(No.2015CB932500)
文摘High-performance solid polymer electrolyte （SPE） has long been desired for the next-generation high energy density and safe rechargeable lithium batteries. A SPE composed of 80 wt% lithium bis（trifluo-romethanesulfonyl）imide （LiTFSI）, 20% poly（ethylene carbonate） （PEC） and a polyamide （PA） fiber membrane backbone was prepared by solution-casting method. This solid electrolyte exhibits quite high ionic conductivity and lithium ion transference number （t＋）, and excellent mechanical strength. The as-prepared solid electrolyte shows good wettability to porous electrodes during cycles, which is beneficial to form ionically conductive phase throughout porous electrodes. All-solid-state LiFePO4lLi cells assembled with the as-prepared solid electrolyte deliver a high initial discharge specific capacity of 125.7 mAh·g^-1 and good cycling stability at 55 ℃ （93.4% retention at 1C after 200 cycles）, and superior cycle performance. Outstanding electrochemical performance can be mainly ascribed to the improved ionic conductivity in the entire porous electrodes due to the good wettability of SPE.
基金supported by the National Key R&D Program of China(grant no.2022YFB4202200)the Fundamental Research Funds for the Central Universities,China.
文摘Alkaline water electrolysis is a practical route for large-scale green hydrogen production to assist decarbonization,whereby carbon dioxide emissions are limited.However,the use of this process in hydrogen evolution reaction(HER)is hampered by the alkaline solution,which leads to slow H_(2)O dissociation kinetics,especially when nickel–molybdenum(NiMo)alloy catalysts are utilized;thus,an improvement of this approach for effective HER activity is desirable.In this work,a porous phosphide NiMo-based(NiMoP)alloy electrode catalyst was engineered using a multistep electrodeposition method.Various experiments,combined with theoretical calculations,confirmed that the phosphide incorporation in the NiMo alloys promoted alkaline HER performance at a high current density of 1000 mA cm^(−2)with the potential−0.191 V.The evaluation of the effect of electrodeposition current density on HER performance revealed that the P content indeed positively impacted the accompanying alkaline HER performance,attributable to phosphide contribution in the electron reconstruction.Density functional theory(DFT)calculations demonstrated that the P atom promoted the loss of Mo electrons and hindered Ni from gaining electrons.This charge reconstruction allowed the optimization of the H^(*)adsorption,contributing to a stronger H_(2)O adsorption and encouraging H-OH^(*)bond breakage.Our current approach may provide the possibility of designing high-performance alkaline HER electrodes at high current density.
基金This work was financially supported by the National Natural Science Foundation of China (No. 90510001).
文摘Graphite material was used as the electrode for an all-vanadium redox flow battery, and the electrode was modified by transition metallic ions to enhance its electrochemical behavior. An porous graphite composite electrode has high specific surface area and high current density. The electrode modified by transition metallic ions has improved catalysis behavior that can catalyze the V（Ⅱ）-V（Ⅴ） redox reaction showed by cyclic voltammograms. This article studied the impedance of the modified electrode by electrochemical impedance spectroscopy （EIS）, and approved that the electrode modified by Co^2＋ and Mn^2＋ has a lower charge transfer resistance than the non-modified electrode. The effect of average particle size distribution is at lower frequencies that the slope of Warburg impedance is reduced by large particle size distribution. The voltage efficiency of the Co^2＋ modified electrode test cell is 81.5%, which is higher than that of the non-modified electrode.
基金This work is supported by the National Natural Science Foundation of China(Nos.51705334 and 51975384)the Shenzhen Science&Technology Projects(Nos.JCYJ20180305125025855 and JCYJ20200109105618137).
文摘Three-dimensional(3D)grid porous electrodes introduce vertically aligned pores as a convenient path for the transport of lithium-ions(Li-ions),thereby reducing the total transport distance of Li-ions and improving the reaction kinetics.Although there have been other studies focusing on 3D electrodes fabricated by 3D printing,there still exists a gap between electrode design and their electrochemical performance.In this study,we try to bridge this gap through a comprehensive investigation on the effects of various electrode parameters including the electrode porosity,active material particle diameter,electrode electronic conductivity,electrode thickness,line width,and pore size on the electrochemical performance.Both numerical simulations and experimental investigations are conducted to systematically examine these effects.3D grid porous Li_(4)Ti_(5)O_(12)(LTO)thick electrodes are fabricated by low temperature direct writing technology and the electrodes with the thickness of 1085μm and areal mass loading of 39.44 mg·cm^(−2) are obtained.The electrodes display impressive electrochemical performance with the areal capacity of 5.88 mAh·cm^(−2)@1.0 C,areal energy density of 28.95 J·cm^(−2)@1.0 C,and areal power density of 8.04 mW·cm^(−2)@1.0 C.This study can provide design guidelines for obtaining 3D grid porous electrodes with superior electrochemical performance.
