3D Interlaced Networks of VO(OH)₂ Nanoflakes Wrapped with Graphene Oxide Nanosheets as Electrodes for Energy Storage Devices

The evolution of newfangled electrode materials with excellent properties has gained tremendous attention in order to meet the requirements applied to flexible energy devices. Vanadium oxides have attracted attention in the field of energy storage, and exploration for novel vanadium-based materials applied to energy storage has received much focus recently. Vanadium oxyhydroxide [VO(OH)2], which has rarely been given much attention, may deserve wider attention because of its great potential for energy storage. To play to their full strengths, it is an excellent way to hybridize with carbon materials such as reduced graphene oxide (rGO), which has superior conductivity and structural stability. Herein, we develop a novel 3D composite constructed from VO(OH)2 nanoflakes wrapped with rGO nanosheets [denoted as 3D VO(OH)2/rGO] as enhanced-performance electrodes for symmetric energy storage devices. 3D VO(OH)2/rGO is synthesized by a one-step hydrothermal route, and this novel composite possesses a unique architecture and intimate interaction, which endows VO(OH)2/rGO with a remarkable electrochemical performance. A VO(OH)2/rGO electrode yields a high specific capacitance of 512 F·g–1 (1024 C·g–1) at 0.5 A·g–1 within −1.2 to +0.8 V. Impressively and unexpectedly, the assembled VO(OH)2/rGO symmetric supercapacitor exhibits the integration of desirable flexibility, 2.4 V high voltage, and high energy density, which reaches 56.26 Wh·kg–1 at 104.16 W·kg–1. After charging for 100 s, two devices in series can light red and blue light-emitting diodes for 12 and 5 min, respectively. This work not only enriches the research of VO(OH)2 but also offers new opportunities for assembling high-performance energy storage devices.