Investigation on mesoporous bimetallic tungstate nanostructure for high-performance solid- state supercapattery

Abstract

Identification of electrode materials with excellent specific capacity and energy density are significant factors for the development of high-performance supercapattery device. Transition metal tungstate is an emerging electroactive material for supercapattery due to its excellent electrical conductivity and electrochemical properties. Herein, the mesoporous Ni(1-x)Co(x)WO4 nanomaterials were synthesized by a onestep hydrothermal method as an anode material for supercapattery. The apparent discrepancy in mesoporous structures was incited by varying the stoichiometric ratio of Ni/Co in the Ni((1-x))Co((x))WO(4 )system which lead to an increase in the electrochemical properties. Among the synthesized electrode materials, Ni(0.5)Co(0.5)WO(4 )electrode material delivers the high specific capacity of 634.55 Cg(-1) at 1 Ag-1 with an excellent rate capability of 92% after 10,000 cycles at 10 Ag-1. The solid-state supercapattery constructed with Ni0.5Co0.5WO4 and reduced graphene oxide as positive and negative electrodes, respectively. The device exhibits the maximum specific capacity of 134.70 Cg(-1) at 0.5 Ag-1 and energy density of 56.12 Wh kg(-1) at 500 W kg(-1) with long-term cyclic stability (90% capacity retentively after 20,000 cycles). The high performance of this electrode material has been attributed to the synergetic effect between bimetallic (Ni and Co) redox centers, a mesoporous structure that provides a larger redox cites, rich electrical conductivity, shorter diffusion length, and faster electrochemical kinetic rates for electrochemical reactions. (C) 2021 Elsevier B.V. All rights reserved.