Flexible Solid-State Symmetric Supercapacitors Using HxWO3@Reduced Graphene Oxide Composite with High Volumetric Energy and Power Densities

We have synthesized hydrogen tungsten oxide decorated reduced graphene oxide (HxWO3@rGO) composite with different precursor weight ratios of WS2 and GO, of which the WG1-2 system, produced from WS2 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(-2) at 1 mA cm(-2) current density with retention of 61.4 % at 20 mA cm(-2) current density. This HxWO3@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(-3) and ultrahigh energy density of 1.6 mW h cm(-3) at 1469.43 mW cm(-3) power density.