Developing high-performance anode materials is crucial for the advancement of sodium-ion capacitors with high-energy density and large power density.Bimetallic oxides exhibit a high specific capacity due to their syne...Developing high-performance anode materials is crucial for the advancement of sodium-ion capacitors with high-energy density and large power density.Bimetallic oxides exhibit a high specific capacity due to their synergistic effects in electrochemical processes.However,challenges such as poor electrical conductivity,slow ion transport,and volume expansion severely limit their development.In this study,Co_(2)VO_(4)@C-1.5 was synthesized through a straightforward method involving solvent-heating and carbonization via calcination.The synergistic effect of Co and V,mitigation of volume expansion by the carbon-coated layer,enhancement of pseudocapacitive behavior and improved electrical conductivity of Co_(2)VO_(4)@C-1.5 contribute to its superior electrochemical performance.The specific capacity of Co_(2)VO_(4)@C-1.5 remained steady at 288.8 and 171.7 mAh g^(-1)after 100 and 500 cycles at 100 and 1000 mA g^(-1),respectively.Density functional theory(DFT)calculations show a notable reduction in the energy barrier of Co_(2)VO_(4)@C-1.5.Furthermore,the assembled sodium-ion capacitor Co_(2)VO_(4)@C-1.5//AC demonstrates high-energy density(108.5 Wh kg^(-1)at 99.8 W kg^(-1)),remarkable power density(38.2 Wh kg^(-1)at 12,000 W kg^(-1)),and longcycle stability(capacity retention of 80.6%after 6000 cycles).The design and optimization of the carbon-coated structure provide valuable insights for the development of bimetallic oxide materials in sodium-ion capacitors(SICs).展开更多
The development of effective and low-cost catalysts for overall water splitting is essential for clean production of hydrogen from water.In this paper,we report the synthesis of cobalt-vanadium（Co-V）bimetal-based ca...The development of effective and low-cost catalysts for overall water splitting is essential for clean production of hydrogen from water.In this paper,we report the synthesis of cobalt-vanadium（Co-V）bimetal-based catalysts for the effective water splitting.The Co_2V_2O_7·xH_2O nanoplates containing both Co and V elements were selected as the precursors.After the calcination under NH_3atmosphere,the Co_2VO_4and Co/VN could be obtained just by tuning the calcination temperature.Electrochemical tests indicated that the Co-V bimetal-based materials could be used as active hydrogen evolution reaction（HER）and oxygen evolution reaction（OER）catalyst by regulating their structure.The Co/VN showed good performance for HER with the onset potential of68 mV and can achieve a current density of 10 mA cm^（-2）at an overpotential of 92 m V.Meanwhile,the Co_2VO_4exhibited the obvious OER performance with overpotential of 300 mV to achieve a current density of 10 mA cm^（-2）.When the Co_2VO_4and Co/VN were used as the anode and cathode in a twoelectrode system,respectively,the cell needed a voltage of1.65 V to achieve 10 mA cm^（-2）together with good stability.This work would be indicative to constructing Co-V bimetalbased catalysts for the catalytic application.展开更多
基金financially supported by the Applied Basic Research Project of Qinghai Province(No.2024-ZJ-766)the Youth Innovation Promotion Association CAS(No.2018466)
文摘Developing high-performance anode materials is crucial for the advancement of sodium-ion capacitors with high-energy density and large power density.Bimetallic oxides exhibit a high specific capacity due to their synergistic effects in electrochemical processes.However,challenges such as poor electrical conductivity,slow ion transport,and volume expansion severely limit their development.In this study,Co_(2)VO_(4)@C-1.5 was synthesized through a straightforward method involving solvent-heating and carbonization via calcination.The synergistic effect of Co and V,mitigation of volume expansion by the carbon-coated layer,enhancement of pseudocapacitive behavior and improved electrical conductivity of Co_(2)VO_(4)@C-1.5 contribute to its superior electrochemical performance.The specific capacity of Co_(2)VO_(4)@C-1.5 remained steady at 288.8 and 171.7 mAh g^(-1)after 100 and 500 cycles at 100 and 1000 mA g^(-1),respectively.Density functional theory(DFT)calculations show a notable reduction in the energy barrier of Co_(2)VO_(4)@C-1.5.Furthermore,the assembled sodium-ion capacitor Co_(2)VO_(4)@C-1.5//AC demonstrates high-energy density(108.5 Wh kg^(-1)at 99.8 W kg^(-1)),remarkable power density(38.2 Wh kg^(-1)at 12,000 W kg^(-1)),and longcycle stability(capacity retention of 80.6%after 6000 cycles).The design and optimization of the carbon-coated structure provide valuable insights for the development of bimetallic oxide materials in sodium-ion capacitors(SICs).
基金supported by the Key Program Projects of the National Natural Science Foundation of China (21631004)the National Natural Science Foundation of China (21601055, 21571054 and 21401048)+1 种基金the Natural Science Foundation of Heilongjiang Province (B2017008)Heilongjiang University Excellent Youth Foundation
文摘The development of effective and low-cost catalysts for overall water splitting is essential for clean production of hydrogen from water.In this paper,we report the synthesis of cobalt-vanadium（Co-V）bimetal-based catalysts for the effective water splitting.The Co_2V_2O_7·xH_2O nanoplates containing both Co and V elements were selected as the precursors.After the calcination under NH_3atmosphere,the Co_2VO_4and Co/VN could be obtained just by tuning the calcination temperature.Electrochemical tests indicated that the Co-V bimetal-based materials could be used as active hydrogen evolution reaction（HER）and oxygen evolution reaction（OER）catalyst by regulating their structure.The Co/VN showed good performance for HER with the onset potential of68 mV and can achieve a current density of 10 mA cm^（-2）at an overpotential of 92 m V.Meanwhile,the Co_2VO_4exhibited the obvious OER performance with overpotential of 300 mV to achieve a current density of 10 mA cm^（-2）.When the Co_2VO_4and Co/VN were used as the anode and cathode in a twoelectrode system,respectively,the cell needed a voltage of1.65 V to achieve 10 mA cm^（-2）together with good stability.This work would be indicative to constructing Co-V bimetalbased catalysts for the catalytic application.
