Transition metal selenides have aroused great attention in recent years due to their high theoretical capacity.However,the huge volume fluctuation generated by conversion reaction during the charge/discharge process r...Transition metal selenides have aroused great attention in recent years due to their high theoretical capacity.However,the huge volume fluctuation generated by conversion reaction during the charge/discharge process results in the significant electrochemical performance reduction.Herein,the carbon-regulated copper(I)selenide(Cu_(2)Se@C)is designed to significantly promote the interface stability and ion diffusion for selenide electrodes.The systematic X-ray spectroscopies characterizations and density functional theory(DFT)simulations reveal that the Cu–Se–C bonding forming on the surface of Cu2Se not only improves the electronic conductivity of Cu_(2)Se@C but also retards the volume change during electrochemical cycling,playing a pivotal role in interface regulation.Consequently,the storage kinetics of Cu_(2)Se@C is mainly controlled by the capacitance process diverting from the ion diffusion-controlled process of Cu2Se.When employed this distinctive Cu_(2)Se@C as anode active material in Li coin cell configuration,the ultrahigh specific capacity of 810.3 mA·h·g^(−1)at 0.1 A·g^(−1)and the capacity retention of 83%after 1,500 cycles at 5 A·g^(−1)is achieved,implying the best Cu-based Li^(+)-storage capacity reported so far.This strategy of heterojunction combined with chemical bonding regulation opens up a potential way for the development of advanced electrodes for battery storage systems.展开更多
“Intrinsic”strategies for manipulating the local electronic structure and coordination environment of defect-regulated materials can optimize electrochemical storage performance.Nevertheless,the structure–activity ...“Intrinsic”strategies for manipulating the local electronic structure and coordination environment of defect-regulated materials can optimize electrochemical storage performance.Nevertheless,the structure–activity relationship between defects and charge storage is ambiguous,which may be revealed by constructing highly ordered vacancy structures.Herein,we demonstrate molybdenum carbide MXene nanosheets with customized in-plane chemical ordered vacancies(Mo_(1.33)CT_(x)),by utilizing selective etching strategies.Synchrotron-based X-ray characterizations reveal that Mo atoms in Mo1.33CTx show increased average valence of+4.44 compared with the control Mo_(2)CT_(x).Benefited from the introduced atomic active sites and high valence of Mo,Mo_(1.33)CT_(x)achieves an outstanding capacity of 603 mAh·g^(−1)at 0.2 A·g^(−1),superior to most original MXenes.Li+storage kinetics analysis and density functional theory(DFT)simulations show that this optimized performance ensues from the more charge compensation during charge–discharge process,which enhances Faraday reaction compared with pure Mo_(2)CT_(x).This vacancy manipulation provides an efficient way to realize MXene’s potential as promising electrodes.展开更多
The geometrically multiplied development of 2D MXenes has already promoted the prosperity of various fields of scientific researches especially but not limited in energy storage and conversion.Notably,cation intercala...The geometrically multiplied development of 2D MXenes has already promoted the prosperity of various fields of scientific researches especially but not limited in energy storage and conversion.Notably,cation intercalation can improve the interlayer spacing of MXenes resulting in tunable physical and chemical properties.Moreover,the synchrotron radiation X-ray characterizations have also shown high potential on exploring the property and structu re of cation intercalated MXe nes.This review is mainly focused on the recent achievements of cation intercalated MXenes through different methods on energy storage systems.Synchrotron-based X-ray absorption spectroscopic characterizations are emphasized to probe the local coordination and electronic structure in intercalated MXenes.The outlook of cation intercalation on MXenes and their applications are also discus sed.展开更多
基金financially supported in part by the National Key Research and Development Program of China(No.2020YFA0405800)the National Natural Science Foundation of China(NSFC,Nos.U1932201 and U2032113)+4 种基金Youth Innovation Promotion Association of Chinese Academy of Sciences(CAS)(No.2022457)CAS Collaborative Innovation Program of Hefei Science Center(No.2020HSC-CIP002)CAS International Partnership Program(No.211134KYSB20190063)the Fundamental Research Funds for the Central Universities(No.WK2060000039)L.S.acknowledges the support from the Institute of Energy,Hefei Comprehensive National Science Center,University Synergy Innovation Program of Anhui Province(No.GXXT-2020-002).
文摘Transition metal selenides have aroused great attention in recent years due to their high theoretical capacity.However,the huge volume fluctuation generated by conversion reaction during the charge/discharge process results in the significant electrochemical performance reduction.Herein,the carbon-regulated copper(I)selenide(Cu_(2)Se@C)is designed to significantly promote the interface stability and ion diffusion for selenide electrodes.The systematic X-ray spectroscopies characterizations and density functional theory(DFT)simulations reveal that the Cu–Se–C bonding forming on the surface of Cu2Se not only improves the electronic conductivity of Cu_(2)Se@C but also retards the volume change during electrochemical cycling,playing a pivotal role in interface regulation.Consequently,the storage kinetics of Cu_(2)Se@C is mainly controlled by the capacitance process diverting from the ion diffusion-controlled process of Cu2Se.When employed this distinctive Cu_(2)Se@C as anode active material in Li coin cell configuration,the ultrahigh specific capacity of 810.3 mA·h·g^(−1)at 0.1 A·g^(−1)and the capacity retention of 83%after 1,500 cycles at 5 A·g^(−1)is achieved,implying the best Cu-based Li^(+)-storage capacity reported so far.This strategy of heterojunction combined with chemical bonding regulation opens up a potential way for the development of advanced electrodes for battery storage systems.
基金support from the National Key Research and Development Program of China(Nos.2020YFA0405800,2019YFA0405601)the National Natural Science Foundation of China(NSFC)(Nos.U1932201,U2032113)+4 种基金the Youth Innovation Promotion Association of CAS(No.2022457)USTC Research Funds of the Double First-Class Initiative(No.YD2310002003)the Fundamental Research Funds for the Central Universities(Nos.WK2060000039,WK2310000088),Institute of Energy,Hefei Comprehensive National Science Center,University Synergy Innovation Program of Anhui Province(No.GXXT-2020-002)Collaborative Innovation Program of Hefei Science Center,CAS(No.2021HSC-CIP016)C.D.W.(No.202006340190)acknowledge financial support from the China Scholarship Council(CSC).L.S.acknowledges support from the Key Laboratory of Advanced Energy Materials Chemistry(Ministry of Education).
文摘“Intrinsic”strategies for manipulating the local electronic structure and coordination environment of defect-regulated materials can optimize electrochemical storage performance.Nevertheless,the structure–activity relationship between defects and charge storage is ambiguous,which may be revealed by constructing highly ordered vacancy structures.Herein,we demonstrate molybdenum carbide MXene nanosheets with customized in-plane chemical ordered vacancies(Mo_(1.33)CT_(x)),by utilizing selective etching strategies.Synchrotron-based X-ray characterizations reveal that Mo atoms in Mo1.33CTx show increased average valence of+4.44 compared with the control Mo_(2)CT_(x).Benefited from the introduced atomic active sites and high valence of Mo,Mo_(1.33)CT_(x)achieves an outstanding capacity of 603 mAh·g^(−1)at 0.2 A·g^(−1),superior to most original MXenes.Li+storage kinetics analysis and density functional theory(DFT)simulations show that this optimized performance ensues from the more charge compensation during charge–discharge process,which enhances Faraday reaction compared with pure Mo_(2)CT_(x).This vacancy manipulation provides an efficient way to realize MXene’s potential as promising electrodes.
基金financially supported in part by National Key R&D Program of China(No.2017YFA0303500)the National Natural Science Foundation of China(NSFC,Nos.U1932201,11574280,21727801,11605201)+6 种基金Innovative Research Groups of NSFC(No.11621063)the Fundamental Research Funds for the Central Universities(No.WK2310000074)Anhui Provincial Natural Science Foundation(No.1708085QB27)National Natural Science Foundation of China and Ministry of Foreign Affairs and International Cooperation of Italy(NSFC-MAECI,No.51861135202)CAS Key Research Program of Frontier Sciences(No.QYZDB-SSWSLH018)CAS Iterdisciplinary Innovation Team and National Postdoctoral Program for Innovative Talents(No.BX20190315)the support from Key Laboratory of Advanced Energy Materials Chemistry(Ministry of Education),Nankai University(111 project,No.B12015)。
文摘The geometrically multiplied development of 2D MXenes has already promoted the prosperity of various fields of scientific researches especially but not limited in energy storage and conversion.Notably,cation intercalation can improve the interlayer spacing of MXenes resulting in tunable physical and chemical properties.Moreover,the synchrotron radiation X-ray characterizations have also shown high potential on exploring the property and structu re of cation intercalated MXe nes.This review is mainly focused on the recent achievements of cation intercalated MXenes through different methods on energy storage systems.Synchrotron-based X-ray absorption spectroscopic characterizations are emphasized to probe the local coordination and electronic structure in intercalated MXenes.The outlook of cation intercalation on MXenes and their applications are also discus sed.