The development of sulfur cathodes with high areal capacity and high energy density is crucial for the practical application of lithium-sulfur batteries(LSBs).LSBs can be built by employing(ultra)high-loading sulfur c...The development of sulfur cathodes with high areal capacity and high energy density is crucial for the practical application of lithium-sulfur batteries(LSBs).LSBs can be built by employing(ultra)high-loading sulfur cathodes,which have rarely been realized due to massive passivation and shuttling.Herein,microspheres of a carbon-carbon nitride composite(C@CN)with large mesopores are fabricated via molecular cooperative assembly.Using the C@CN-based electrodes,the effects of the large mesopores and N-functional groups on the electrochemical behavior of sulfur in LSB cells are thoroughly investigated under ultrahigh sulfur-loading conditions(>15 mgS cm^(-2)).Furthermore,for high-energy-density LSBs,the C@CN powders are pelletized into a thick free-standing electrode(thickness:500^m;diameter:11 mm)via a simple briquette process;here,the total amount of energy stored by the LSB cells is 39 mWh,corresponding to a volumetric energy density of 440 Wh L-1 with an areal capacity of 24.9 and 17.5 mAh cm^(-2) at 0.47 and 4.7 mA cm^(-2),respectively(at 24mgS cm^(-2)).These results have significantly surpassed most recent records due to the synergy among the large mesopores,(poly)sulfide-philic surfaces,and thick electrodes.The developed strategy with its potential for scale-up successfully fills the gap between laboratory-scale cells and practical cells without sacrificing the high areal capacity and high energy density,providing a solid foundation for the development of practical LSBs.展开更多
Herein,non-carbonized wood-based electrodes and separators with well-aligned channels and excellent mechanical properties are developed for supercapacitors.To enhance the conductivity and boost the capacitance,Ti_(3)C...Herein,non-carbonized wood-based electrodes and separators with well-aligned channels and excellent mechanical properties are developed for supercapacitors.To enhance the conductivity and boost the capacitance,Ti_(3)C_(2)(MXene)nanosheets with high electrical conductivity and excellent electrochemical activity are loaded into the wood cells via self-assembly triggered by fast evaporating water in Ti_(3)C_(2)suspension.By the assistance of positive charged polydopamine microspheres with large surface area,the self-restacking of Ti_(3)C_(2)nanosheets can be avoided and the high mass loading(50 wt%)can be achieved due to the extra driving force for Ti_(3)C_(2)absorption.Benefiting from the conductive Ti_(3)C_(2)nanosheets with massive active sites and the multiple well-aligned channels in wood with efficient transportation pathways for charge carriers,the as-designed free-standing electrode shows a large areal capacitance of 1060 mF cm^(-2)at 0.5 mA cm^(-2)and high capacitance retention of 67%at 10 mA cm^(-2).Also,this electrode is highly size-customizable,showing a good ability to be industrially processed into various shapes and dimensions.Furthermore,an all-wood based supercapacitor with Ti_(3)C_(2)/wood composites as two layers of electrodes and a wood slice as the separator is fabricated,presenting a high energy density of 10.5μW h cm^(-2)at 389.9μW cm^(-2).展开更多
Electrocatalytic nitrogen reduction reaction is a carbon-free and energy-saving strategy for efficient synthesis of ammonia under ambient conditions.Here,we report the synthesis of nanosized Bi2O3 particles grown on f...Electrocatalytic nitrogen reduction reaction is a carbon-free and energy-saving strategy for efficient synthesis of ammonia under ambient conditions.Here,we report the synthesis of nanosized Bi2O3 particles grown on functionalized exfoliated graphene(Bi2O3/FEG)via a facile electrochemical deposition method.The obtained free-standing Bi2O3/FEG achieves a high Faradaic efficiency of 11.2%and a large NH3 yield of 4.21±0.14μgNH3 h^-1 cm^-2 at-0.5 V versus reversible hydrogen electrode in 0.1 M Na2SO4,better than that in the strong acidic and basic media.Benefiting from its strong interaction of Bi 6p band with the N2p orbitals,binder-free characteristic,and facile electron transfer,Bi2O3/FEG achieves superior catalytic performance and excellent long-term stability as compared with most of the previous reported catalysts.This study is significant to design low-cost,high-efficient Bi-based electrocatalysts for electrochemical ammonia synthesis.展开更多
Supercapacitors are efficient and versatile energy storage devices,offering remarkable power density,fast charge/discharge rates,and exceptional cycle life.As research continues to push the boundaries of their perform...Supercapacitors are efficient and versatile energy storage devices,offering remarkable power density,fast charge/discharge rates,and exceptional cycle life.As research continues to push the boundaries of their performance,electrode fabrication techniques are critical aspects influencing the overall capabilities of supercapacitors.Herein,we aim to shed light on the advantages offered by dry electrode processing for advanced supercapacitors.Notably,our study explores the performance of these electrodes in three different types of electrolytes:organic,ionic liquids,and quasi-solid states.By examining the impact of dry electrode processing on various electrode and electrolyte systems,we show valuable insights into the versatility and efficacy of this technique.The supercapacitors employing dry electrodes demonstrated significant improvements compared with conventional wet electrodes,with a lifespan extension of+45%in organic,+192%in ionic liquids,and+84%in quasi-solid electrolytes.Moreover,the increased electrode densities achievable through the dry approach directly translate to improved volumetric outputs,enhancing energy storage capacities within compact form factors.Notably,dry electrode-prepared supercapacitors outperformed their wet electrode counterparts,exhibiting a higher energy density of 6.1 Wh cm^(-3)compared with 4.7 Wh cm^(-3)at a high power density of 195Wcm^(-3),marking a substantial 28%energy improvement in the quasi-solid electrolyte.展开更多
Electrophoretic deposition in conjunction with electrochemical reduction was used to make flexible free-standing graphene-like films. Firstly, graphene oxide （GO） film was deposited on graphite substrate by electrop...Electrophoretic deposition in conjunction with electrochemical reduction was used to make flexible free-standing graphene-like films. Firstly, graphene oxide （GO） film was deposited on graphite substrate by electrophoretic deposition method, and then reduced by subsequent electrochemical reduction of GO to obtain reduced GO （ERGO） film with high electrochemical performance. The morphology, structure and electrochemical performance of the prepared graphene-like film were confirmed by SEM, XRD and FT-IR. These unique materials were found to provide high specific capacitance and good cycling stability. The high specific capacitance of 254 F/g was obtained from cyclic voltammetry measurement at a scan rate of 10 mV/s. When the current density increased to 83.3 A/g, the specific capacitance values still remained 132 F/g. Meanwhile, the high powder density of 39.1 kW/kg was measured at energy density of 11.8 W-h/kg in 1 mol/L H2SO4 solution. Furthermore, at a constant scan rate of 50 mV/s, 97.02% of its capacitance was retained for 1000 cycles. These promising results were attributed to the unique assembly structure of graphene film and low contact resistance, which indicated their potential application to electrochemical capacitors.展开更多
Highly sensitive, selective, and stable hydrogen peroxide （H2O2） detection using nanozyme-based catalysts are desirable for practical applications. Herein, vertical α-FeOOH nanowires were successfully grown on the ...Highly sensitive, selective, and stable hydrogen peroxide （H2O2） detection using nanozyme-based catalysts are desirable for practical applications. Herein, vertical α-FeOOH nanowires were successfully grown on the surface of carbon fiber paper （CFP） via a low-temperature hydrothermal procedure. The formation of vertical α-FeOOH nanowires is ascribed to the structure-directing role of sodium dodecyl sulfate. The resulting free-standing electrode with one-dimensional （1D） nanowires offers oriented channels for fast charge transfer, excellent electrical contact between the electrocatalyst and the current collector, and good mechanical stability and reproducibility. Thus, it can serve as an efficient electrocatalyst for the reduction and sensitive detection of H2O2. The relation of the oxidation current of H202 with the concentration is linear from 0.05 to 0.5 mM with a sensitivity of -0.194 mA/（mM.cm2） and a low detection limit of 18μM. Furthermore, the portability in the geometric tailor and easy device fabrication allow extending the general applicability of this free-standing electrode to chemical and biological sensors.展开更多
The keen interest in fuel cells and metal-air batteries stimulates a great deal of research on the development of a cost-efficient and high-performance catalyst as an alternative to traditional Pt to boost the sluggis...The keen interest in fuel cells and metal-air batteries stimulates a great deal of research on the development of a cost-efficient and high-performance catalyst as an alternative to traditional Pt to boost the sluggish oxygen reduction reaction(ORR)at the cathode.Herein,we report a facile and scalable strategy for the large-scale preparation of a free-standing and flexible porous atomically dispersed Fe-N-doped carbon microtube(FeSAC/PCMT)sponge.Benefiting from its unique structure that greatly facilitates the catalytic kinetics,mass transport,and electron transfer,our FeSAC/PCMT electrode exhibits excellent performance with an ORR potential of 0.942 V at^(-3) mA cm^(-2).When the FeSAC/PCMT sponge was directly used as an oxygen electrode for liquid-state and flexible solid-state zinc-air batteries,high peak power densities of 183.1 and 58.0 mW cm^(-2) were respectively achieved,better than its powdery counterpart and commercial Pt/C catalyst.Experimental and theoretical investigation results demonstrate that such ultrahigh ORR performance can be attributed to atomically dispersed Fe-N_(5) species in FeSAC/PCMT.This study presents a cost-effective and scalable strategy for the fabrication of highly efficient and flexible oxygen electrodes,provides a significant new insight into the catalytic mechanisms,and helps to realize significant advances in energy devices.展开更多
While transition-metal oxides such as α-MoO_(3)provide high capacity,their use is limited by modest electronic conductivity and electrochemical instability in aqueous electrolytes.Two-dimensional(2D)MXenes,offer meta...While transition-metal oxides such as α-MoO_(3)provide high capacity,their use is limited by modest electronic conductivity and electrochemical instability in aqueous electrolytes.Two-dimensional(2D)MXenes,offer metallic conductivity,but their capacitance is limited in aqueous electrolytes.Insertion of partially solvated cations into Ti_(3)C_(2)MXene from lithium-based water-in-salt(WIS)electrolytes enables charge storage at positive potentials,allowing a wider potential window and higher capacitance.Herein,we demonstrate that α-MoO_(3)/Ti_(3)C_(2)hybrids combine the high capacity of α-MoO_(3)and conductivity of Ti_(3)C_(2)in WIS(19.8 m LiCI)electrolyte in a wide1.8 V voltage window.Cyclic voltammograms reveal multiple redox peaks from α-MoO_(3)in addition to the well-separated peaks of Ti_(3)C_(2)in the hybrid electrode.This leads to a higher specific charge and a higher rate capability compared to a carbon and binder containing α-MoO_(3)electrode.These results demonstrate that the addition of MXene to less conductive oxides eliminates the need for conductive carbon additives and binders,leads to a larger amount of charge stored,and increases redox capacity at higher rates.In addition,MXene encapsulated α-MoO_(3)showed improved electrochemical stability,which was attributed to the suppressed dissolution of α-MoO_(3).The work suggests that oxide/MXene hybrids are promising for energy storage.展开更多
Vanadium redox flow batteries(VRFBs)are a means of large-scale energy storage due to their excellent scalability,safety,long cycling life,and decoupled power and energy capacities.However,the slow redox kinetics of va...Vanadium redox flow batteries(VRFBs)are a means of large-scale energy storage due to their excellent scalability,safety,long cycling life,and decoupled power and energy capacities.However,the slow redox kinetics of vanadium species on conventional carbon electrodes remains a major limitation to their performance.We investigated the deposition of carbon black,carbon nanotubes,and electrochemically exfoliated graphene(Exf-Gr)onto thermally-activated carbon paper(ACP)by spray coating to increase the electrode electrocatalytic activity.The modified electrodes were characterized using scanning electron microscopy,X-ray diffraction,Raman spectroscopy,X-ray photoelectron microscopy,and surface area analysis,while their electrochemical properties were evaluated by cyclic voltammetry,electrochemical impedance spectroscopy,and singlecell VRFB testing.Among the modified electrodes,Exf-Gr/ACP had the best performance,achieving a 2.9-fold reduction in charge transfer resistance compared to pristine ACP and delivering 2.5 times the discharge capacity in single-cell tests.This improvement is attributed to Exf-Gr’s high surface area,favorable catalytic activity,and excellent dispersion on the ACP substrate.Surface modification with electrochemically exfoliated graphene is a highly effective strategy for improving the electrode performance in VRFB systems,with significant implications for large-scale energy storage.展开更多
The development of shape-customizable and bulk flexible electrochemical devices through processing technologies as versatile as those used for plastics promises to revolutionize the future of battery technology.Howeve...The development of shape-customizable and bulk flexible electrochemical devices through processing technologies as versatile as those used for plastics promises to revolutionize the future of battery technology.However,this pursuit has been fundamentally hindered by the absence of transformative battery materials capable of delivering the necessary electrochemical functions,robust interface adhesion,and,crucially,the suitable rheological properties required for on-demand shaping.In this work,we introduce a concept of a multifunctional plasticine electrode matrix(PEM)featuring nano-interpenetrating networks(nano-IPN)to address this challenge.Utilizing the nonflammable liquid-electrolyte hydration combined with conductive nanomaterials,we have realized a PEM in the form of a multifunctional nanocomposite that integrates ion and electron conduction,component binding,non-flammability,and plasticine-like moldability.With this PEM,we have successfully fabricated a variety of bulk-flexible electrodes with high mass loading of active material(AM)(>70 wt%)using industry-friendly extrusion and compression molding techniques.Moreover,these high AM-loading composite electrodes achieve an unparalleled bulk conformability and flexibility,remaining structurally intact even under severe mechanical stress.Ultimately,we have successfully produced shape-patternable and flexible batteries via extrusion molding.This study underscores the potential of the PEM to revolutionize battery microstructures,interfaces,manufacturing processes,and performance characteristics.展开更多
Objective:To investigate the spatial gradient of intraoperative impedance across the cochlear electrode array in pediatric cochlear implant recipients and assess its potential as a physiological indicator for the elec...Objective:To investigate the spatial gradient of intraoperative impedance across the cochlear electrode array in pediatric cochlear implant recipients and assess its potential as a physiological indicator for the electrode-neural interface.Methods:A prospective observational study involving 56 pediatric patients underwent cochlear implantation with Cochlear Nucleus devices.Intraoperative polarized impedance and electrically evoked compound action potential(ECAP)threshold were recorded across all 1232 electrodes using AutoNRT software.Eight electrodes with open-or short-circuit were excluded,leaving 1,224 for analysis.Impedance values were categorized by cochlear region(basal,middle,apical),and electrodes with elevated impedance(10-20 kΩ)were analyzed for regional distribution and clinical relevance.Data were analyzed for spatial patterns and correlation with the ECAP threshold profiles.Results:A consistent basal-to-apical increase in impedance was observed(7.7±1.9,9.2±1.4,10.8±1.5 kΩ;p<0.001).Impedance and ECAP threshold were weakly correlated(ρ=-0.20,p<0.001;β=-1.26,p<0.001),with a positive association in the apical region(ρ=0.12,p=0.048).Electrodes with higher impedance(1020 kΩ)were less likely to show elevated or absent TNRT(OR=0.175,p=0.02).The impedance gradient persisted across age groups and was significantly correlated with ECAP threshold patterns.Conclusion:Intraoperative impedance monitoring reveals a strong and physiologically consistent gradient,with higher values in apical electrodes.This gradient reflects anatomical and tissue interface variations,which may offer a valuable physiological indicator for intraoperative electrode positioning and neural interface integrity.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
To enhance the electrochemical performance of lithium-ion battery anodes with higher silicon content,it is essential to engineer their microstructure for better lithium-ion transport and mitigated volume change as wel...To enhance the electrochemical performance of lithium-ion battery anodes with higher silicon content,it is essential to engineer their microstructure for better lithium-ion transport and mitigated volume change as well.Herein,we suggest an effective approach to control the micropore structure of silicon oxide(SiO_(x))/artificial graphite(AG)composite electrodes using a perforated current collector.The electrode features a unique pore structure,where alternating high-porosity domains and low-porosity domains markedly reduce overall electrode resistance,leading to a 20%improvement in rate capability at a 5C-rate discharge condition.Using microstructure-resolved modeling and simulations,we demonstrate that the patterned micropore structure enhances lithium-ion transport,mitigating the electrolyte concentration gradient of lithium-ion.Additionally,perforating current collector with a chemical etching process increases the number of hydrogen bonding sites and enlarges the interface with the SiO_(x)/AG composite electrode,significantly improving adhesion strength.This,in turn,suppresses mechanical degradation and leads to a 50%higher capacity retention.Thus,regularly arranged micropore structure enabled by the perforated current collector successfully improves both rate capability and cycle life in SiO_(x)/AG composite electrodes,providing valuable insights into electrode engineering.展开更多
Ceramic cells promise ideal energy conversion and storage devices,making the development of efficient and robust air electrodes crucial for their application.In this study,a Ba_(0.4)Sr_(0.5)Cs_(0.1)Co_(0.7)Fe_(0.2)Nb_...Ceramic cells promise ideal energy conversion and storage devices,making the development of efficient and robust air electrodes crucial for their application.In this study,a Ba_(0.4)Sr_(0.5)Cs_(0.1)Co_(0.7)Fe_(0.2)Nb_(0.1)O_(3−δ)(BSCCFN)air electrode,based on Ba_(0.5)Sr_(0.5)Co_(0.8)Fe_(0.2)O_(3−δ)(BSCF),is designed using a perovskite A-B-site ionic Lewis acid strength(ISA)polarization distribution strategy and is successfully applied in both oxygen-ion conducting solid oxide fuel cells(O-SOFCs)and proton-conducting reversible protonic ceramic cells(R-PCCs).When BSCCFN is used as the air electrode in O-SOFCs,a peak power density(PPD)of 1.45 W cm^(−2)is achieved at 650°C,whereas in R-PCCs,a PPD of 1.13 W cm^(−2)and a current density of−1.8 A cm^(−2)at 1.3 V are achieved at the same temperature and show stable reversibility over 100 h.Experimental measurements and theoretical calculations demonstrate that low-ISA Cs+doping accelerates the reaction kinetics of both oxygen ions and protons,while high-ISA Nb^(5+)doping enhances electrode stability.The synergistic effect of Cs^(+)and Nb^(5+)co-doping in the BSCCFN electrode lies in the ISA polarization distribution,which weakens the Co/Fe–O bond covalency,thereby promoting oxygen vacancy formation and facilitating the conduction of oxygen ions and protons.展开更多
Economical,stable,and corrosion-resistant catalytic electrodes are still urgently needed for the oxygen evolution reaction(OER)in water and seawater.Herein,a mild electroless plating strategy is used to achieve large-...Economical,stable,and corrosion-resistant catalytic electrodes are still urgently needed for the oxygen evolution reaction(OER)in water and seawater.Herein,a mild electroless plating strategy is used to achieve large-scale preparation of the“integrated”phosphorus-based precatalyst(FeP-NiP)on nickel foam(NF),which is in situ reconstructed into a highly active and corrosion-resistant(Fe)NiOOH phase for OER.The interaction between phosphate anions(PO_(x)^(y-))and iron ions(Fe^(3+))tunes the electronic structure of the catalytic phase to further enhance OER kinetics.The integrated FeP-NiP@NF electrode exhibits low overpotentials for OER in alkaline water/seawater,requiring only 275/289,320/336,and 349/358 mV to reach 0.1,0.5,and 1.0 A cm^(−2),respectively.The in situ reconstructed PO_(x)^(y-)anion electrostatically repels Cl−in seawater electrolytes,allowing stable operation for over 7 days at 1.0 A cm^(−2) in extreme electrolytes(1.0 M KOH+seawater and 6.0 M KOH+seawater),demonstrating industrial-level stability.This study overcomes the complex synthesis limitations of P-based materials through innovative material design,opening new avenues for electrochemical energy conversion.展开更多
The ever-increasing demands for advanced lithium-ion batteries with high energy density have greatly stimulated the pursuit of thick electrodes with high active material loading.However,it is not feasible to prepare t...The ever-increasing demands for advanced lithium-ion batteries with high energy density have greatly stimulated the pursuit of thick electrodes with high active material loading.However,it is not feasible to prepare thick electrodes with traditional coating methods due to mechanical instability.Herein,using single-wall carbon nanotubes(SWCNT)as conductive carbon and binder,free-standing LiMn_(2)O_(4) thick electrodes(F-LMO)with ultrahigh-mass loading up to~190 mg cm^(-2)were prepared by vacuum filtration combined with freeze-drying.The thick electrodes with~30 mg cm^(-2)mass loading achieved a high specific capacity of 106.7 mAh g^(-1)with a good capacity retention of 94%over 50 cycles at 0.5 C,which was superior to the traditional coating electrodes(~20 mg cm^(-2))of 99.3 mAh g^(-1)with 95%because of the enhanced electronic conductivity originated from SWCNT.In addition,the high active material ratio of 97.5 wt%,near-theoretical reversible capacity,and high mass loading gave ultrathick F-LMO electrodes(600μm)of~190 mg cm^(-2)with a remarkable areal capacity of 20 mAh cm^(-2).Moreover,the concentration polarization that occurred in the thick F-LMO electrodes under high current density was discussed via electrochemical stimulation.展开更多
Electrochemical reduction of molecular O2 to hydrogen peroxide(H2O2)offers a promising solution for water purification and environmental remediation.Here,we design a hierarchical free-standing single-Co-atom(with Co-N...Electrochemical reduction of molecular O2 to hydrogen peroxide(H2O2)offers a promising solution for water purification and environmental remediation.Here,we design a hierarchical free-standing single-Co-atom(with Co-N4 coordination)electrode for oxygen reduction reaction(ORR)via a two-electron pathway to make H2O2 in acidic media.The current density of the single-Co-atom electrode reached 51 mA/cm2 at 0.1 V vs reversible hydrogen electrode,lasting for more than 10 hours of continuous operation with H2O2 selectivity greater than 80%.Toward practical application,the single-Co-atom electrode was directly used to assemble an electrochemical cell to produce H2O2 at a rate of 676 mol/kgcat/h with a cell voltage of about 1.6 V.展开更多
Aqueous hybrid supercapacitors are promising due to their low cost and high safety. Herein, a freestanding battery-type electrode of Bi2O3 nanoflake@C on carbon cloth is designed for aqueous sodium ion hybrid supercap...Aqueous hybrid supercapacitors are promising due to their low cost and high safety. Herein, a freestanding battery-type electrode of Bi2O3 nanoflake@C on carbon cloth is designed for aqueous sodium ion hybrid supercapacitors. Due to the integration of nanoarray architecture and the conductive carbon,the Bi2O3@C electrode exhibits a high specific capacity of 207 mAh/g at 2 A/g（6C）, good rate capability and cycling stability（133 m Ah/g after 1000 cycles）. With the activated carbon as the capacitive electrode and neutral sodium salts as the electrolyte, a 1.9 V hybrid supercapacitor is assembled,delivering a high energy density of 18.94 Wh/kg. The device can still maintain 72.3% of initial capacity after 650 cycles. The present work holds great promise for developing next-generation hybrid supercapacitors.展开更多
Ultrathin free-standing electrospun carbon nanofiber web（ECNFW） used for the electrodes of the vanadium flow battery（VFB） has been fabricated by the electrospinning technique followed by the carbonization process ...Ultrathin free-standing electrospun carbon nanofiber web（ECNFW） used for the electrodes of the vanadium flow battery（VFB） has been fabricated by the electrospinning technique followed by the carbonization process in this study to reduce the ohmic polarization of the VFB. The microstructure, surface chemistry and electrochemical performance of ECNFW carbonized at various temperatures from 800 to 1400 °C have been investigated. The results show that ECNFW carbonized at 1100 °C exhibits the highest electrocatalytic activity toward the V;/V;redox reaction, and its electrocatalytic activity decreases along with the increase of carbonization temperature due to the drooping of the surface functional groups.While for the VO;/VO;redox couple, the electrocatalytic activity of ECNFW carbonized above 1100 °C barely changes as the carbonization temperature rises. It indicates that the surface functional groups could function as the reaction sites for the V;/V;redox couple, but have not any catalytic effect for the VO;/VO;redox couple. And the single cell test result suggests that ECNFW carbonized at 1100 °C is a promising material as the VFB electrode and the VFB with ECNFW electrodes obtains a super low internal resistance of 250 mΩ cm;.展开更多
An easily manipulative approach was presented to fabricate electrodes using free-standing single-walled carbon nanotube （SWCNT） films grown directly by chemical vapor deposition. Electrochemical properties of the el...An easily manipulative approach was presented to fabricate electrodes using free-standing single-walled carbon nanotube （SWCNT） films grown directly by chemical vapor deposition. Electrochemical properties of the electrodes were investigated. In comparison with the post-deposited SWCNT papers, the directly grown SWCNT film electrodes manifested enhanced electrochemical properties and sensitivity of sensors as well as excellent electrocatalytic activities. A transition from macroelectrode to nanoelectrode behaviours was observed with the increase of scan rate. The heat treatment of the SWCNT film electrodes increased the current signals of electrochemical analyser and background current, because the heat-treatment of the SWCNTs in air could create more oxide defects on the walls of the SWCNTs and make the surfaces of SWCNTs more hydrophilic. The excellent electrochemical properties of the directly grown and heat-treated free-standing SWCNT film electrodes show the potentials in biological and electrocatalytic applications.展开更多
基金the R&D Convergence Program of NST(National Research Council of Science&Technology)of the Republic of Korea(CAP-15-02-KBSI)a National Research Foundation of Korea(NRF)grant funded by the Korean Government(MSIT)(No.2019R1C1C1007745)a National Research Foundation of Korea(NRF)grant funded by the Korean Government(Ministry of Science,ICT&Future Planning)(No.2019R1A4A2001527).
文摘The development of sulfur cathodes with high areal capacity and high energy density is crucial for the practical application of lithium-sulfur batteries(LSBs).LSBs can be built by employing(ultra)high-loading sulfur cathodes,which have rarely been realized due to massive passivation and shuttling.Herein,microspheres of a carbon-carbon nitride composite(C@CN)with large mesopores are fabricated via molecular cooperative assembly.Using the C@CN-based electrodes,the effects of the large mesopores and N-functional groups on the electrochemical behavior of sulfur in LSB cells are thoroughly investigated under ultrahigh sulfur-loading conditions(>15 mgS cm^(-2)).Furthermore,for high-energy-density LSBs,the C@CN powders are pelletized into a thick free-standing electrode(thickness:500^m;diameter:11 mm)via a simple briquette process;here,the total amount of energy stored by the LSB cells is 39 mWh,corresponding to a volumetric energy density of 440 Wh L-1 with an areal capacity of 24.9 and 17.5 mAh cm^(-2) at 0.47 and 4.7 mA cm^(-2),respectively(at 24mgS cm^(-2)).These results have significantly surpassed most recent records due to the synergy among the large mesopores,(poly)sulfide-philic surfaces,and thick electrodes.The developed strategy with its potential for scale-up successfully fills the gap between laboratory-scale cells and practical cells without sacrificing the high areal capacity and high energy density,providing a solid foundation for the development of practical LSBs.
基金the Natural Science Foundation of the Jiangsu Higher Education Institutions of China(20KJB220008)Start-up Funds for Scientific Research at the Nanjing Forestry University(163020126).
文摘Herein,non-carbonized wood-based electrodes and separators with well-aligned channels and excellent mechanical properties are developed for supercapacitors.To enhance the conductivity and boost the capacitance,Ti_(3)C_(2)(MXene)nanosheets with high electrical conductivity and excellent electrochemical activity are loaded into the wood cells via self-assembly triggered by fast evaporating water in Ti_(3)C_(2)suspension.By the assistance of positive charged polydopamine microspheres with large surface area,the self-restacking of Ti_(3)C_(2)nanosheets can be avoided and the high mass loading(50 wt%)can be achieved due to the extra driving force for Ti_(3)C_(2)absorption.Benefiting from the conductive Ti_(3)C_(2)nanosheets with massive active sites and the multiple well-aligned channels in wood with efficient transportation pathways for charge carriers,the as-designed free-standing electrode shows a large areal capacitance of 1060 mF cm^(-2)at 0.5 mA cm^(-2)and high capacitance retention of 67%at 10 mA cm^(-2).Also,this electrode is highly size-customizable,showing a good ability to be industrially processed into various shapes and dimensions.Furthermore,an all-wood based supercapacitor with Ti_(3)C_(2)/wood composites as two layers of electrodes and a wood slice as the separator is fabricated,presenting a high energy density of 10.5μW h cm^(-2)at 389.9μW cm^(-2).
基金financially supported by Liaoning Revitalization Talents Program—Pan Deng Scholars(XLYC1802005)Liaoning BaiQianWan Talents Program+4 种基金the National Science Fund of Liaoning Province for Excellent Young ScholarsScience and Technology Innovative Talents Support Program of Shenyang(RC180166)Australian Research Council(ARC)through Discovery Early Career Researcher Award(DE150101306)and Linkage Project(LP160100927)Faculty of Science Strategic Investment Funding of University of NewcastleCSIRO Newcastl Energy Centre。
文摘Electrocatalytic nitrogen reduction reaction is a carbon-free and energy-saving strategy for efficient synthesis of ammonia under ambient conditions.Here,we report the synthesis of nanosized Bi2O3 particles grown on functionalized exfoliated graphene(Bi2O3/FEG)via a facile electrochemical deposition method.The obtained free-standing Bi2O3/FEG achieves a high Faradaic efficiency of 11.2%and a large NH3 yield of 4.21±0.14μgNH3 h^-1 cm^-2 at-0.5 V versus reversible hydrogen electrode in 0.1 M Na2SO4,better than that in the strong acidic and basic media.Benefiting from its strong interaction of Bi 6p band with the N2p orbitals,binder-free characteristic,and facile electron transfer,Bi2O3/FEG achieves superior catalytic performance and excellent long-term stability as compared with most of the previous reported catalysts.This study is significant to design low-cost,high-efficient Bi-based electrocatalysts for electrochemical ammonia synthesis.
基金funding of the joint Polish-German project SUPILMIX(PR-1173/27)by the German Research Foundation(DFG,Deutsche Forschungsgemeinschaft)+1 种基金funding from the Alexander von Humboldt Foundation.D.L.the German Chemical Industry Fund for the financial support through a Liebig Fellowship.
文摘Supercapacitors are efficient and versatile energy storage devices,offering remarkable power density,fast charge/discharge rates,and exceptional cycle life.As research continues to push the boundaries of their performance,electrode fabrication techniques are critical aspects influencing the overall capabilities of supercapacitors.Herein,we aim to shed light on the advantages offered by dry electrode processing for advanced supercapacitors.Notably,our study explores the performance of these electrodes in three different types of electrolytes:organic,ionic liquids,and quasi-solid states.By examining the impact of dry electrode processing on various electrode and electrolyte systems,we show valuable insights into the versatility and efficacy of this technique.The supercapacitors employing dry electrodes demonstrated significant improvements compared with conventional wet electrodes,with a lifespan extension of+45%in organic,+192%in ionic liquids,and+84%in quasi-solid electrolytes.Moreover,the increased electrode densities achievable through the dry approach directly translate to improved volumetric outputs,enhancing energy storage capacities within compact form factors.Notably,dry electrode-prepared supercapacitors outperformed their wet electrode counterparts,exhibiting a higher energy density of 6.1 Wh cm^(-3)compared with 4.7 Wh cm^(-3)at a high power density of 195Wcm^(-3),marking a substantial 28%energy improvement in the quasi-solid electrolyte.
基金Projects(21361020,21061012)supported by the National Natural Science Foundation of ChinaProject(NZ12156)supported by the Natural Science Foundation of Ningxia,ChinaProject(N-09-13)supported by Project of State Key Laboratory of Catalysis,Dalian Institute of Chemical Physics of the Chinese Academy of Sciences
文摘Electrophoretic deposition in conjunction with electrochemical reduction was used to make flexible free-standing graphene-like films. Firstly, graphene oxide （GO） film was deposited on graphite substrate by electrophoretic deposition method, and then reduced by subsequent electrochemical reduction of GO to obtain reduced GO （ERGO） film with high electrochemical performance. The morphology, structure and electrochemical performance of the prepared graphene-like film were confirmed by SEM, XRD and FT-IR. These unique materials were found to provide high specific capacitance and good cycling stability. The high specific capacitance of 254 F/g was obtained from cyclic voltammetry measurement at a scan rate of 10 mV/s. When the current density increased to 83.3 A/g, the specific capacitance values still remained 132 F/g. Meanwhile, the high powder density of 39.1 kW/kg was measured at energy density of 11.8 W-h/kg in 1 mol/L H2SO4 solution. Furthermore, at a constant scan rate of 50 mV/s, 97.02% of its capacitance was retained for 1000 cycles. These promising results were attributed to the unique assembly structure of graphene film and low contact resistance, which indicated their potential application to electrochemical capacitors.
基金We gratefully acknowledge the support of this research by the Key Program Projects of the National Natural Science Foundation of China （No. 21031001）, the National Natural Science Foundation of China （Nos. 21371053 and 21573062）, the Cultivation Fund of the Key Scientific and Technical Innovation Project, Program for Innovative Research Team in University （No. IRT-1237）, Application Technology Research and Development Projects in Harbin （No. 2013AE4BW051）, International Science ＆ Technology Cooperation Program of China （No. 2014DFR41110）, and the Foundation of HeilongjJLang Province of China （No. QC2013C009）.
文摘Highly sensitive, selective, and stable hydrogen peroxide （H2O2） detection using nanozyme-based catalysts are desirable for practical applications. Herein, vertical α-FeOOH nanowires were successfully grown on the surface of carbon fiber paper （CFP） via a low-temperature hydrothermal procedure. The formation of vertical α-FeOOH nanowires is ascribed to the structure-directing role of sodium dodecyl sulfate. The resulting free-standing electrode with one-dimensional （1D） nanowires offers oriented channels for fast charge transfer, excellent electrical contact between the electrocatalyst and the current collector, and good mechanical stability and reproducibility. Thus, it can serve as an efficient electrocatalyst for the reduction and sensitive detection of H2O2. The relation of the oxidation current of H202 with the concentration is linear from 0.05 to 0.5 mM with a sensitivity of -0.194 mA/（mM.cm2） and a low detection limit of 18μM. Furthermore, the portability in the geometric tailor and easy device fabrication allow extending the general applicability of this free-standing electrode to chemical and biological sensors.
基金supported by the start-up fund from Kunming University of Science and Technology,the National Natural Science Foundation of China (Grants 52102046,51872293,52130209,52072375)Liaoning Revitalization Talents Program (XLYC2002037)Basic Research Project of Natural Science Foundation of Shandong Province,China (ZR2019ZD49).
文摘The keen interest in fuel cells and metal-air batteries stimulates a great deal of research on the development of a cost-efficient and high-performance catalyst as an alternative to traditional Pt to boost the sluggish oxygen reduction reaction(ORR)at the cathode.Herein,we report a facile and scalable strategy for the large-scale preparation of a free-standing and flexible porous atomically dispersed Fe-N-doped carbon microtube(FeSAC/PCMT)sponge.Benefiting from its unique structure that greatly facilitates the catalytic kinetics,mass transport,and electron transfer,our FeSAC/PCMT electrode exhibits excellent performance with an ORR potential of 0.942 V at^(-3) mA cm^(-2).When the FeSAC/PCMT sponge was directly used as an oxygen electrode for liquid-state and flexible solid-state zinc-air batteries,high peak power densities of 183.1 and 58.0 mW cm^(-2) were respectively achieved,better than its powdery counterpart and commercial Pt/C catalyst.Experimental and theoretical investigation results demonstrate that such ultrahigh ORR performance can be attributed to atomically dispersed Fe-N_(5) species in FeSAC/PCMT.This study presents a cost-effective and scalable strategy for the fabrication of highly efficient and flexible oxygen electrodes,provides a significant new insight into the catalytic mechanisms,and helps to realize significant advances in energy devices.
基金supported by the Fluid Interface Reacions and Transport(FIRST)Centeran Energy Frontier Research Center supported by the U.S.Department of Energy,Office of Science,Basic Energy Sciences+1 种基金Synthesis,XRD,and SEM characterization of α-MoO_(3) were supported as a part of the Center for Mesoscale Transport PropertiesEnergy Frontier Research Center supported by the U.S.Department of Energy,Office of Science,Basic Energy Sciences,under award#DE-SC0012673
文摘While transition-metal oxides such as α-MoO_(3)provide high capacity,their use is limited by modest electronic conductivity and electrochemical instability in aqueous electrolytes.Two-dimensional(2D)MXenes,offer metallic conductivity,but their capacitance is limited in aqueous electrolytes.Insertion of partially solvated cations into Ti_(3)C_(2)MXene from lithium-based water-in-salt(WIS)electrolytes enables charge storage at positive potentials,allowing a wider potential window and higher capacitance.Herein,we demonstrate that α-MoO_(3)/Ti_(3)C_(2)hybrids combine the high capacity of α-MoO_(3)and conductivity of Ti_(3)C_(2)in WIS(19.8 m LiCI)electrolyte in a wide1.8 V voltage window.Cyclic voltammograms reveal multiple redox peaks from α-MoO_(3)in addition to the well-separated peaks of Ti_(3)C_(2)in the hybrid electrode.This leads to a higher specific charge and a higher rate capability compared to a carbon and binder containing α-MoO_(3)electrode.These results demonstrate that the addition of MXene to less conductive oxides eliminates the need for conductive carbon additives and binders,leads to a larger amount of charge stored,and increases redox capacity at higher rates.In addition,MXene encapsulated α-MoO_(3)showed improved electrochemical stability,which was attributed to the suppressed dissolution of α-MoO_(3).The work suggests that oxide/MXene hybrids are promising for energy storage.
基金supported by the University of Seoul’s 2025 Research Fund.
文摘Vanadium redox flow batteries(VRFBs)are a means of large-scale energy storage due to their excellent scalability,safety,long cycling life,and decoupled power and energy capacities.However,the slow redox kinetics of vanadium species on conventional carbon electrodes remains a major limitation to their performance.We investigated the deposition of carbon black,carbon nanotubes,and electrochemically exfoliated graphene(Exf-Gr)onto thermally-activated carbon paper(ACP)by spray coating to increase the electrode electrocatalytic activity.The modified electrodes were characterized using scanning electron microscopy,X-ray diffraction,Raman spectroscopy,X-ray photoelectron microscopy,and surface area analysis,while their electrochemical properties were evaluated by cyclic voltammetry,electrochemical impedance spectroscopy,and singlecell VRFB testing.Among the modified electrodes,Exf-Gr/ACP had the best performance,achieving a 2.9-fold reduction in charge transfer resistance compared to pristine ACP and delivering 2.5 times the discharge capacity in single-cell tests.This improvement is attributed to Exf-Gr’s high surface area,favorable catalytic activity,and excellent dispersion on the ACP substrate.Surface modification with electrochemically exfoliated graphene is a highly effective strategy for improving the electrode performance in VRFB systems,with significant implications for large-scale energy storage.
基金financial support from the National Natural Science Foundation of China(52473248,52203123,52125301,22279070 and U21A20170)the State Key Laboratory of Polymer Materials Engineering(Grant No:sklpme 2023-1-05 and sklpme 2024-2-04)+3 种基金the Ministry of Science and Technology of China(No.2019YFA0705703)the Sichuan Science and Technology Program(2023NSFSC0991 and 2025ZNSFSC1411)the Fundamental Research Funds for the Central Universitiespartially sponsored by the Double First-Class Construction Funds of Sichuan University.
文摘The development of shape-customizable and bulk flexible electrochemical devices through processing technologies as versatile as those used for plastics promises to revolutionize the future of battery technology.However,this pursuit has been fundamentally hindered by the absence of transformative battery materials capable of delivering the necessary electrochemical functions,robust interface adhesion,and,crucially,the suitable rheological properties required for on-demand shaping.In this work,we introduce a concept of a multifunctional plasticine electrode matrix(PEM)featuring nano-interpenetrating networks(nano-IPN)to address this challenge.Utilizing the nonflammable liquid-electrolyte hydration combined with conductive nanomaterials,we have realized a PEM in the form of a multifunctional nanocomposite that integrates ion and electron conduction,component binding,non-flammability,and plasticine-like moldability.With this PEM,we have successfully fabricated a variety of bulk-flexible electrodes with high mass loading of active material(AM)(>70 wt%)using industry-friendly extrusion and compression molding techniques.Moreover,these high AM-loading composite electrodes achieve an unparalleled bulk conformability and flexibility,remaining structurally intact even under severe mechanical stress.Ultimately,we have successfully produced shape-patternable and flexible batteries via extrusion molding.This study underscores the potential of the PEM to revolutionize battery microstructures,interfaces,manufacturing processes,and performance characteristics.
文摘Objective:To investigate the spatial gradient of intraoperative impedance across the cochlear electrode array in pediatric cochlear implant recipients and assess its potential as a physiological indicator for the electrode-neural interface.Methods:A prospective observational study involving 56 pediatric patients underwent cochlear implantation with Cochlear Nucleus devices.Intraoperative polarized impedance and electrically evoked compound action potential(ECAP)threshold were recorded across all 1232 electrodes using AutoNRT software.Eight electrodes with open-or short-circuit were excluded,leaving 1,224 for analysis.Impedance values were categorized by cochlear region(basal,middle,apical),and electrodes with elevated impedance(10-20 kΩ)were analyzed for regional distribution and clinical relevance.Data were analyzed for spatial patterns and correlation with the ECAP threshold profiles.Results:A consistent basal-to-apical increase in impedance was observed(7.7±1.9,9.2±1.4,10.8±1.5 kΩ;p<0.001).Impedance and ECAP threshold were weakly correlated(ρ=-0.20,p<0.001;β=-1.26,p<0.001),with a positive association in the apical region(ρ=0.12,p=0.048).Electrodes with higher impedance(1020 kΩ)were less likely to show elevated or absent TNRT(OR=0.175,p=0.02).The impedance gradient persisted across age groups and was significantly correlated with ECAP threshold patterns.Conclusion:Intraoperative impedance monitoring reveals a strong and physiologically consistent gradient,with higher values in apical electrodes.This gradient reflects anatomical and tissue interface variations,which may offer a valuable physiological indicator for intraoperative electrode positioning and neural interface integrity.
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supported by the National Research Foundation of Korea(NRF)grant funded by the Korean government(MSIT)(No.NRF-2021M3H4A1A02048529)the Ministry of Trade,Industry and Energy(MOTIE)of the Korean government under grant No.RS-2022-00155854support from the DGIST Supercomputing and Big Data Center.
文摘To enhance the electrochemical performance of lithium-ion battery anodes with higher silicon content,it is essential to engineer their microstructure for better lithium-ion transport and mitigated volume change as well.Herein,we suggest an effective approach to control the micropore structure of silicon oxide(SiO_(x))/artificial graphite(AG)composite electrodes using a perforated current collector.The electrode features a unique pore structure,where alternating high-porosity domains and low-porosity domains markedly reduce overall electrode resistance,leading to a 20%improvement in rate capability at a 5C-rate discharge condition.Using microstructure-resolved modeling and simulations,we demonstrate that the patterned micropore structure enhances lithium-ion transport,mitigating the electrolyte concentration gradient of lithium-ion.Additionally,perforating current collector with a chemical etching process increases the number of hydrogen bonding sites and enlarges the interface with the SiO_(x)/AG composite electrode,significantly improving adhesion strength.This,in turn,suppresses mechanical degradation and leads to a 50%higher capacity retention.Thus,regularly arranged micropore structure enabled by the perforated current collector successfully improves both rate capability and cycle life in SiO_(x)/AG composite electrodes,providing valuable insights into electrode engineering.
基金funding from the National Natural Science Foundation of China (Award 91745203) supplemented by Central Universities’ Basic Research Funds.
文摘Ceramic cells promise ideal energy conversion and storage devices,making the development of efficient and robust air electrodes crucial for their application.In this study,a Ba_(0.4)Sr_(0.5)Cs_(0.1)Co_(0.7)Fe_(0.2)Nb_(0.1)O_(3−δ)(BSCCFN)air electrode,based on Ba_(0.5)Sr_(0.5)Co_(0.8)Fe_(0.2)O_(3−δ)(BSCF),is designed using a perovskite A-B-site ionic Lewis acid strength(ISA)polarization distribution strategy and is successfully applied in both oxygen-ion conducting solid oxide fuel cells(O-SOFCs)and proton-conducting reversible protonic ceramic cells(R-PCCs).When BSCCFN is used as the air electrode in O-SOFCs,a peak power density(PPD)of 1.45 W cm^(−2)is achieved at 650°C,whereas in R-PCCs,a PPD of 1.13 W cm^(−2)and a current density of−1.8 A cm^(−2)at 1.3 V are achieved at the same temperature and show stable reversibility over 100 h.Experimental measurements and theoretical calculations demonstrate that low-ISA Cs+doping accelerates the reaction kinetics of both oxygen ions and protons,while high-ISA Nb^(5+)doping enhances electrode stability.The synergistic effect of Cs^(+)and Nb^(5+)co-doping in the BSCCFN electrode lies in the ISA polarization distribution,which weakens the Co/Fe–O bond covalency,thereby promoting oxygen vacancy formation and facilitating the conduction of oxygen ions and protons.
基金funding support from Natural Science Foundation of Shanghai(Grant No.23ZR1443900)the National Natural Science Foundation of China(Grant Nos.22178309,22476131 and 22176127)。
文摘Economical,stable,and corrosion-resistant catalytic electrodes are still urgently needed for the oxygen evolution reaction(OER)in water and seawater.Herein,a mild electroless plating strategy is used to achieve large-scale preparation of the“integrated”phosphorus-based precatalyst(FeP-NiP)on nickel foam(NF),which is in situ reconstructed into a highly active and corrosion-resistant(Fe)NiOOH phase for OER.The interaction between phosphate anions(PO_(x)^(y-))and iron ions(Fe^(3+))tunes the electronic structure of the catalytic phase to further enhance OER kinetics.The integrated FeP-NiP@NF electrode exhibits low overpotentials for OER in alkaline water/seawater,requiring only 275/289,320/336,and 349/358 mV to reach 0.1,0.5,and 1.0 A cm^(−2),respectively.The in situ reconstructed PO_(x)^(y-)anion electrostatically repels Cl−in seawater electrolytes,allowing stable operation for over 7 days at 1.0 A cm^(−2) in extreme electrolytes(1.0 M KOH+seawater and 6.0 M KOH+seawater),demonstrating industrial-level stability.This study overcomes the complex synthesis limitations of P-based materials through innovative material design,opening new avenues for electrochemical energy conversion.
基金financial support from the National Natural Science Foundation of China(52122407,52174285,and 51974370)the Program of Huxiang Young Talents(2019RS2002)the Innovation and entrepreneurship project of Hunan Province,China(Grant No.2020GK4051)。
文摘The ever-increasing demands for advanced lithium-ion batteries with high energy density have greatly stimulated the pursuit of thick electrodes with high active material loading.However,it is not feasible to prepare thick electrodes with traditional coating methods due to mechanical instability.Herein,using single-wall carbon nanotubes(SWCNT)as conductive carbon and binder,free-standing LiMn_(2)O_(4) thick electrodes(F-LMO)with ultrahigh-mass loading up to~190 mg cm^(-2)were prepared by vacuum filtration combined with freeze-drying.The thick electrodes with~30 mg cm^(-2)mass loading achieved a high specific capacity of 106.7 mAh g^(-1)with a good capacity retention of 94%over 50 cycles at 0.5 C,which was superior to the traditional coating electrodes(~20 mg cm^(-2))of 99.3 mAh g^(-1)with 95%because of the enhanced electronic conductivity originated from SWCNT.In addition,the high active material ratio of 97.5 wt%,near-theoretical reversible capacity,and high mass loading gave ultrathick F-LMO electrodes(600μm)of~190 mg cm^(-2)with a remarkable areal capacity of 20 mAh cm^(-2).Moreover,the concentration polarization that occurred in the thick F-LMO electrodes under high current density was discussed via electrochemical stimulation.
基金This study was supported by the funds from the Singapore Ministry of Education Academic Research Fund,Tier 1:RG111/15 and RG10/16 and Tier 2:MOE2016-T2-2 to 004.
文摘Electrochemical reduction of molecular O2 to hydrogen peroxide(H2O2)offers a promising solution for water purification and environmental remediation.Here,we design a hierarchical free-standing single-Co-atom(with Co-N4 coordination)electrode for oxygen reduction reaction(ORR)via a two-electron pathway to make H2O2 in acidic media.The current density of the single-Co-atom electrode reached 51 mA/cm2 at 0.1 V vs reversible hydrogen electrode,lasting for more than 10 hours of continuous operation with H2O2 selectivity greater than 80%.Toward practical application,the single-Co-atom electrode was directly used to assemble an electrochemical cell to produce H2O2 at a rate of 676 mol/kgcat/h with a cell voltage of about 1.6 V.
基金supported by grants from the National Natural Science Foundation of China(Nos.51672205 and 21673169)the National Key R&D Program of China(No.2016YFA0202602)+1 种基金the Research Start-Up Fund from Wuhan University of Technologythe Fundamental Research Funds for the Central Universities(Nos.2016IVA083,2017IB005)
文摘Aqueous hybrid supercapacitors are promising due to their low cost and high safety. Herein, a freestanding battery-type electrode of Bi2O3 nanoflake@C on carbon cloth is designed for aqueous sodium ion hybrid supercapacitors. Due to the integration of nanoarray architecture and the conductive carbon,the Bi2O3@C electrode exhibits a high specific capacity of 207 mAh/g at 2 A/g（6C）, good rate capability and cycling stability（133 m Ah/g after 1000 cycles）. With the activated carbon as the capacitive electrode and neutral sodium salts as the electrolyte, a 1.9 V hybrid supercapacitor is assembled,delivering a high energy density of 18.94 Wh/kg. The device can still maintain 72.3% of initial capacity after 650 cycles. The present work holds great promise for developing next-generation hybrid supercapacitors.
基金the financial support from the National Natural Science Foundation of China(Grant nos.21506210 and 51361135701)
文摘Ultrathin free-standing electrospun carbon nanofiber web（ECNFW） used for the electrodes of the vanadium flow battery（VFB） has been fabricated by the electrospinning technique followed by the carbonization process in this study to reduce the ohmic polarization of the VFB. The microstructure, surface chemistry and electrochemical performance of ECNFW carbonized at various temperatures from 800 to 1400 °C have been investigated. The results show that ECNFW carbonized at 1100 °C exhibits the highest electrocatalytic activity toward the V;/V;redox reaction, and its electrocatalytic activity decreases along with the increase of carbonization temperature due to the drooping of the surface functional groups.While for the VO;/VO;redox couple, the electrocatalytic activity of ECNFW carbonized above 1100 °C barely changes as the carbonization temperature rises. It indicates that the surface functional groups could function as the reaction sites for the V;/V;redox couple, but have not any catalytic effect for the VO;/VO;redox couple. And the single cell test result suggests that ECNFW carbonized at 1100 °C is a promising material as the VFB electrode and the VFB with ECNFW electrodes obtains a super low internal resistance of 250 mΩ cm;.
基金supported by the National Natural Science Foundation of Chinathe National Basic Research Program of China (GrantNo. 2005CB623602)+1 种基金the Fund of the Beijing Municipal Education Commission (Grant No. YB20108000101)the Key Item of Knowledge Innovation Project of the Chinese Academy of Sciences (Grant No. KJCX2-YW-M01)
文摘An easily manipulative approach was presented to fabricate electrodes using free-standing single-walled carbon nanotube （SWCNT） films grown directly by chemical vapor deposition. Electrochemical properties of the electrodes were investigated. In comparison with the post-deposited SWCNT papers, the directly grown SWCNT film electrodes manifested enhanced electrochemical properties and sensitivity of sensors as well as excellent electrocatalytic activities. A transition from macroelectrode to nanoelectrode behaviours was observed with the increase of scan rate. The heat treatment of the SWCNT film electrodes increased the current signals of electrochemical analyser and background current, because the heat-treatment of the SWCNTs in air could create more oxide defects on the walls of the SWCNTs and make the surfaces of SWCNTs more hydrophilic. The excellent electrochemical properties of the directly grown and heat-treated free-standing SWCNT film electrodes show the potentials in biological and electrocatalytic applications.
