Owing to the potential ability of metal nanoparticles to enhance the performance of energy storage devices,their catalytic performance has been studied by many researchers.However,a limited number of suitable characte...Owing to the potential ability of metal nanoparticles to enhance the performance of energy storage devices,their catalytic performance has been studied by many researchers.However,a limited number of suitable characterization techniques does not allow fully elucidating their catalytic mechanism.Herein,high‐accuracy operando magnetometry is employed to investigate the catalytic properties of a cobalt oxide electrode for lithium‐ion batteries fabricated by magnetron sputtering.Using this technique,the magnetic responses generated by the Co‐catalyzed reversible formation and decomposition of a polymer/gel‐like film are successfully detected.A series of CoO/Co films are prepared by magnetron sputtering in different environments at various sputtering times to study the influence of Co content and film thickness on their catalytic properties.It is clearly demonstrated that increasing the Co content enhances the magnetic signal associated with the catalysis process.Furthermore,decreasing the electrode thickness increases the area affected by the catalytic reactions,which in turn enhances the corresponding magnetic responses.The obtained results experimentally confirm the catalytic activity of Co metal nanoparticles and provide a scientific guidance for designing advanced energy storage devices.This work also shows that operando magnetometry is a versatile technique for studying the catalytic effects of transition metals.展开更多
Cobalt sulfides are considered as promising candidates for lithium-ion battery(LIB)anode materials with high energy densities.Their energy storage mechanism is widely understood to involve the traditional intercalatio...Cobalt sulfides are considered as promising candidates for lithium-ion battery(LIB)anode materials with high energy densities.Their energy storage mechanism is widely understood to involve the traditional intercalation and conversion reaction.However,these conventional mechanisms are unable to explain the storage capacities of certain materials which exceed the theoretical limit.Here,utilizing advanced in situ magnetometry to detect the magnetization evolution of Co_(1-x) S LIBs in real time,it is demonstrated that the Co-catalytic lithium storage process and interfacial space charge storage mechanism are strongly related to the additional capacity of cobalt sulfides.During discharge,a Co/Li_(2) S interface is formed,wherein the Co nanoparticles and Li_(2) S could store a large amount of polarized electrons Li^(+),respectively.Subsequently,the electrons stored in Co are transferred to the polymeric film,forming radical anions and contributing extra capacity.These findings reveal the charge storage mechanisms of transition metal sulfides and highlight the critical role of magnetic testing in the investigation of energy storage mechanisms.展开更多
文摘Owing to the potential ability of metal nanoparticles to enhance the performance of energy storage devices,their catalytic performance has been studied by many researchers.However,a limited number of suitable characterization techniques does not allow fully elucidating their catalytic mechanism.Herein,high‐accuracy operando magnetometry is employed to investigate the catalytic properties of a cobalt oxide electrode for lithium‐ion batteries fabricated by magnetron sputtering.Using this technique,the magnetic responses generated by the Co‐catalyzed reversible formation and decomposition of a polymer/gel‐like film are successfully detected.A series of CoO/Co films are prepared by magnetron sputtering in different environments at various sputtering times to study the influence of Co content and film thickness on their catalytic properties.It is clearly demonstrated that increasing the Co content enhances the magnetic signal associated with the catalysis process.Furthermore,decreasing the electrode thickness increases the area affected by the catalytic reactions,which in turn enhances the corresponding magnetic responses.The obtained results experimentally confirm the catalytic activity of Co metal nanoparticles and provide a scientific guidance for designing advanced energy storage devices.This work also shows that operando magnetometry is a versatile technique for studying the catalytic effects of transition metals.
基金supported by the Natural Science Foundation of Shandong Province(ZR2020ZD10)the National Natural Science Foundation of China(21775142)Shenzhen Natural Science Fund(20200925154115001 and JCYJ20210324115809026).
基金supported partly by the National Natural Science Foundation of China(22179066)the Natural Science Foundation of Shandong Province(ZR2020MA073).
文摘Cobalt sulfides are considered as promising candidates for lithium-ion battery(LIB)anode materials with high energy densities.Their energy storage mechanism is widely understood to involve the traditional intercalation and conversion reaction.However,these conventional mechanisms are unable to explain the storage capacities of certain materials which exceed the theoretical limit.Here,utilizing advanced in situ magnetometry to detect the magnetization evolution of Co_(1-x) S LIBs in real time,it is demonstrated that the Co-catalytic lithium storage process and interfacial space charge storage mechanism are strongly related to the additional capacity of cobalt sulfides.During discharge,a Co/Li_(2) S interface is formed,wherein the Co nanoparticles and Li_(2) S could store a large amount of polarized electrons Li^(+),respectively.Subsequently,the electrons stored in Co are transferred to the polymeric film,forming radical anions and contributing extra capacity.These findings reveal the charge storage mechanisms of transition metal sulfides and highlight the critical role of magnetic testing in the investigation of energy storage mechanisms.
