Time-intended effect on electrochemical performance of hydrothermally reduced graphene oxide nanosheets: Design and study of solid-state symmetric supercapacitor

Abstract

Self-organized porous sheet-like assemblies have attracted extensive attention for the development of flexible high-performance electrodes. This work demonstrates the facile synthesis and effects of reduction time on the electrochemical performance of porous sheet-like assemblies of reduced graphene oxide (rGO) on carbon cloth. An rGO porous assembly with a reduction time of 4 h exhibited a superior specific capacitance of 456 F/g at a scan rate of 5 mV/s and 223 F/g at a current density of 1 mA/cm2, with ~ 93.9% initial capacity retention over 2000 cycles. A solid-state symmetric supercapacitor device constructed of a rGO4//rGO4 porous assembly achieved a specific capacitance of 45.86 F/g at a scan rate of 5 mV/s and yielded an energy density of 1.27 Wh/kg and specific power of 833.3 W/kg in a PVA-H2SO4 gel polymer electrolyte. Furthermore, the flexible solid-state symmetric device provides outstanding cyclic stability with a 95.3% retention of its initial capacity over 2000 cycles. Thus, electrodes constructed of rGO porous sheets show great potential for flexible and transparent solid-state symmetric energy storage devices.