High-performance flexible all-solid-state micro-supercapacitors based on two-dimensional InSe nanosheets

Abstract Layered metal chalcogenide are emerging candidate materials for high-performance supercapacitor electrode materials. However, poor conductivity resulting from low carrier mobility limits the further improvement of supercapacitor performance based on layered transition metal chalcogenide. Here we prepare flexible interdigital all-solid-state micro-supercapacitors (MSCs) based on layered III-VI metal chalcogenides InSe with high carrier mobility. When the mass ratio of InSe nanosheets to graphene is 1:2, the best performing MSCs exhibit high areal and volumetric capacitances up to 0.72 F cm−2 and 1.79 F cm−3. Moreover, the MSCs show outstanding long-life cycling stability (retaining 93.6% of specific capacitances after 10000 cycles) and excellent mechanical flexibility (remaining capacitance at 98.2% after 2000 cycles under bending angle of 90°). The MSCs have an outstanding power density of 7.31 W cm−3 and a high energy density of 0.48 mWh cm−3.