摘要
Existing rechargeable batteries not only fail to meet the demand for high power applications but also cause heavy metal pollution.Li-ion capacitors(LICs),which can achieve higher charging speeds and energy densities than supercapacitors,have attracted extensive attention.Nevertheless,sluggish Li-ion diffusion of the battery-type anode results in limited rate performance of LICs.Herein,highperformance LICs using both battery and capacitor type Mn_(2)V_(2)O_(7)-graphene(MVO-G)anodes and hempstem-derivated activated carbon(HSAC)cathodes with a large surface area are first reported.In addition to high pseudocapacitance,the MVO-G possesses the advantage of fast Li^(+)storage performance making it a suitable choice for advanced LIC anodes.Graphene is employed to enhance overall conductivity and cycling stability leading to enhanced energy storage.The MVO-G//HSAC LICs exhibit a high energy density of 148.1 Wh kg^(-1) at a power density of 150 W kg^(-1) and 25 Wh kg^(-1) even at15 k W kg^(-1).More importantly,the MVO-G//HSAC LICs also show excellent cycling stability of 90%after15,000 cycles,which is expected for high performance energy storage systems.
基金
the National Natural Science Foundation of China(Grant Nos.21673064 and 51902072)
the China postdoctoral science foundation(Grant Nos.2017M621285 and 2018T110292)
the Fundamental Research Funds for the Central Universities(Grant Nos.HIT.NSRIF.2019040 and 2019041)
the State Key Laboratory of Urban Water Resource and Environment(Harbin Institute of Technology)(No.2020DX11)。
