LAUSR

Abstract 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, high-performance LICs using by both battery and capacitor type Mn2V2O7-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 at 15 kW kg–1. More importantly, the MVO-G//HSAC LICs also show excellent cycling stability of 90% after 15000 cycles, which is expected for high performance energy storage systems.