Chimie douce derived Nickelt Cobalt oxynitride as electrode material for high energy density supercapacitors

Abstract

Bimetallic oxides are considered to be promising electrode materials for electrochemical energy storage devices. This is due to their higher capacity and electrochemical activity. However, their applications are limited due to the structural instabilities. Recently, metal nitrides too have received attention as electrode materials. Given this, bimetallic oxynitrides could offer desirable features present in both metal oxides and nitrides. Bimetallic oxynitride (NiCoOxNy) has so far not been studied as an electrode material for supercapacitors. Furthermore its structural and chemical details are inadequately investigated. Here, mesoporous NiCoOxNy nanostructures with a specific surface area of 93 m2 g−1 are produced from simple soft urea technique. This electrode material gives a specific capacity of 728 C g−1 at 4 A g−1 as opposed to 664 C g−1, for pristine NiCoO2 electrode material. This outstanding performance arises from enhanced conductivity and oxygen vacancies in the oxynitride material. An asymmetric device fabricated using NiCoOxNy nanostructures as the positive electrode material can deliver a desirable energy and power density of 53 Wh kg−1 and 24 kW kg−1, respectively, with cyclic stability of 60% after 10,000 cycles. This study reveals that NiCoOxNy is a promising electrode material for energy storage applications.