Transition metal sulfides(TMSs) are promising candidates for replacing graphite anode in LIBs. However,the low conductivity and structural collapse caused by the large volume change during lithium insertion and extrac...Transition metal sulfides(TMSs) are promising candidates for replacing graphite anode in LIBs. However,the low conductivity and structural collapse caused by the large volume change during lithium insertion and extraction greatly limit its application. Herein, we report a unique design of a two-dimensional(2 D) sandwich structure of N-doped carbon@Co9 S8@graphene(N–C@Co9 S8@G) with multilayer structure. Electrochemical tests reveal that the N–C@Co9 S8@G nanosheets possess a high reversible capacity(1009 mAhg^(-1) at 0.1 Ag^(-1)), and excellent rate capability(422mAhg^(-1) at 10 Ag^(-1)) and long cycle life(853 m Ahg^(-1) at 1Ag^(-1) for 500 cycles). Experimental studies reveal that capacitive storage contributes to the high reversible capacity. The lithium storage kinetics are studied by Galvanostatic intermittent titration technique(GITT) and electrochemical impedance spectroscopy(EIS). Meanwhile, the potential of N–C@Co9 S8@G anode in a full cell using Li Co O2 as the cathode is also demonstrated, exhibiting a high reversible capacity of 300mAhg^(-1) cycles at 0.1Ag^(-1). The strategy proposed in this work paves the way to engineering high performance anodes in LIBs.展开更多
基金financially supported by the National Natural Science Foundation of China (No. 51972182 and 61971252)the Shandong Provincial Science Foundation (ZR2019BF008 and ZR2017JL021)+1 种基金the Youth Innovation Team Project of Shandong Provincial Education Department (2020KJN015)the “Distinguished Taishan Scholar” project。
文摘Transition metal sulfides(TMSs) are promising candidates for replacing graphite anode in LIBs. However,the low conductivity and structural collapse caused by the large volume change during lithium insertion and extraction greatly limit its application. Herein, we report a unique design of a two-dimensional(2 D) sandwich structure of N-doped carbon@Co9 S8@graphene(N–C@Co9 S8@G) with multilayer structure. Electrochemical tests reveal that the N–C@Co9 S8@G nanosheets possess a high reversible capacity(1009 mAhg^(-1) at 0.1 Ag^(-1)), and excellent rate capability(422mAhg^(-1) at 10 Ag^(-1)) and long cycle life(853 m Ahg^(-1) at 1Ag^(-1) for 500 cycles). Experimental studies reveal that capacitive storage contributes to the high reversible capacity. The lithium storage kinetics are studied by Galvanostatic intermittent titration technique(GITT) and electrochemical impedance spectroscopy(EIS). Meanwhile, the potential of N–C@Co9 S8@G anode in a full cell using Li Co O2 as the cathode is also demonstrated, exhibiting a high reversible capacity of 300mAhg^(-1) cycles at 0.1Ag^(-1). The strategy proposed in this work paves the way to engineering high performance anodes in LIBs.
