Owing to high electrical conductivity and ability to reversibly host a variety of inserted ions,2D metallic molybdenum disulfide(1 T-MoS_(2))has demonstrated promising energy storage performance when used as a superca...Owing to high electrical conductivity and ability to reversibly host a variety of inserted ions,2D metallic molybdenum disulfide(1 T-MoS_(2))has demonstrated promising energy storage performance when used as a supercapacitor electrode.However,its charge storage mechanism is still not fully understood,in particular,how the interlayer spacing of 1 T-MoS_(2)would affect its capacitive performance.In this work,molecular dynamics simulations of 1 T-MoS_(2)with interlayer spacing ranging from 0.615 to 1.615 nm have been performed to investigate the resulting charge storage capacity in ionic liquids.Simulations reveal a camel-like capacitance-potential relation,and MoS_(2)with an interlayer spacing of 1.115 nm has the highest volumetric and gravimetric capacitance of118 F cm^(-3)and 42 F g^(-1),respectively.Although ions in MoS_(2)with an interlayer spacing of 1.115 nm diffuse much faster than with interlayer spacings of 1.365 and 1.615 nm,the MoS_(2)with larger interlayer spacing has a much faster-charging process.Our analyses reveal that the ion number density and its charging speed,as well as ion motion paths,have significant impacts on the charging response.This work helps to understand how the interlayer spacing affects the interlayer ion structures and the capacitive performance of MoS_(2),which is important for revealing the charge storage mechanism and designing MoS_(2)supercapacitor.展开更多
基金the financial support from the National Natural Science Foundation of China(51876072)the Hubei Provincial Natural Science Foundation of China(2019CFA002,2020CFA093)+1 种基金Sichuan Science and Technology Program(2019YFG0457)the support from the National Energy Research Scientific Computing Center,a DOE Office of Science User Facility supported by the Office of Science of the U.S.Department of Energy under Contract No.DE-AC0205CH11231
文摘Owing to high electrical conductivity and ability to reversibly host a variety of inserted ions,2D metallic molybdenum disulfide(1 T-MoS_(2))has demonstrated promising energy storage performance when used as a supercapacitor electrode.However,its charge storage mechanism is still not fully understood,in particular,how the interlayer spacing of 1 T-MoS_(2)would affect its capacitive performance.In this work,molecular dynamics simulations of 1 T-MoS_(2)with interlayer spacing ranging from 0.615 to 1.615 nm have been performed to investigate the resulting charge storage capacity in ionic liquids.Simulations reveal a camel-like capacitance-potential relation,and MoS_(2)with an interlayer spacing of 1.115 nm has the highest volumetric and gravimetric capacitance of118 F cm^(-3)and 42 F g^(-1),respectively.Although ions in MoS_(2)with an interlayer spacing of 1.115 nm diffuse much faster than with interlayer spacings of 1.365 and 1.615 nm,the MoS_(2)with larger interlayer spacing has a much faster-charging process.Our analyses reveal that the ion number density and its charging speed,as well as ion motion paths,have significant impacts on the charging response.This work helps to understand how the interlayer spacing affects the interlayer ion structures and the capacitive performance of MoS_(2),which is important for revealing the charge storage mechanism and designing MoS_(2)supercapacitor.
