Flexible Solid‐State Symmetric Supercapacitors Using H_xWO₃@Reduced Graphene Oxide Composite with High Volumetric Energy and Power Densities

Abstract

We have synthesized hydrogen tungsten oxide decorated reduced graphene oxide (H x WO 3 @rGO) composite with different precursor weight ratios of WS 2 and GO, of which the WG1-2 system, produced from WS 2 and GO in the 1 : 2 weight ratio by treatment with hydrogen peroxide followed by hydrothermal treatment, shows high areal capacitance of 409 mF cm À 2 at 1 mA cm À 2 current density with retention of 61.4 % at 20 mA cm À 2 current density. This H x WO 3 @rGO composite is drop-cast onto graphite layer-coated on scotch tape to design a flexible supercapacitor. The flexible solid-state symmetric supercapacitor based on the WG1-2 composite shows a high volumetric capacitance of 3.56 F cm À 3 and ultrahigh energy density of 1.6 mW h cm À 3 at 1469.43 mW cm À 3 power density.

Hierarchical Transition Metal Oxide Arrays Grown on Graphene‐Based Fibers with Enhanced Interface by Thin Layer of Carbon toward Solid‐State Asymmetric Supercapacitors

“…The slope of log i vs log v plot is charge storage kinetic parameter (b). For totally diffusion‐controlled process, the value of b is 0.5; and for totally capacitive charge storage nature, the value is 1 . The log i and log v values of GCF@NC@NCO electrode for anodic potential of 0.05, 0.15, 0.25 and 0.35 V vs Hg/HgO are calculated and represented in Figure S7.…”