Successful synthesis of interconnected Co0.85Se nanosheets with high pore volume and its electrochemical performance in supercapacitors

Abstract

Interconnected Co0.85Se nanosheets have been prepared by a facile hydrothermal method via tuning reaction time to control the chemical constitution and the morphology. The nanosheets morphology of Co0.85Se offers sufficient electron transfer and short ion diffusion pathway, which can favor the fast transfer of electrolyte ions. The Co0.85Se electrode exhibits specific capacitance of 980 F g− 1 at 10 A g− 1 with high cycling life stability (8.3% loss after 5000 cycles) and good conductivity. The assembled Co0.85Se//AC asymmetric supercapacitor (ASC) device exhibits a high energy density of 46.2 Wh kg− 1 at a power density of 807.4 W kg− 1 and still maintained 29.3 Wh kg− 1 at a power density of 15981.8 W kg− 1 with excellent cycling performance (90.01% capacitance retention over 5000 cycles). The impressive results indicate that such unique interconnected Co0.85Se nanosheets are promising electrode materials for high-performance supercapacitors.