An advanced asymmetric supercapacitor based on a binder-free electrode fabricated from ultrathin CoMoO4 nano-dandelions

Abstract

Fabrication of nanostructures with controllable size and morphology is an important area of research and technology. This article aims at demonstrating a facile, low cost and reproducible mild hydrothermal procedure for the synthesis of dandelion-shape cobalt molybdenum oxide nanostructures (CoMoO₄). Interestingly, CoMoO₄ supported on a nickel foam (NF) substrate appeared in the dandelion-shape (ND) and ordered nano-arrays. Morphology characterizations and electrochemical investigations of the ND-CoMoO₄/NF were carried out using different electron microscopy, spectroscopy and electrochemical techniques. A maximum specific capacitance of 2100 F g⁻¹ at a discharge current of 1 A g⁻¹ was calculated for the ND-CoMoO₄/NF electrode in KOH solution. Notably, more than 92% of its initial capacitance was maintained after 3000 successive charge/discharge cycles. Moreover an asymmetric supercapacitor (ASC) assembled using ND-CoMoO₄/NF in combination with the rGO/NF electrode. It was observed that the specific energy of the ASC only decreases from 26 to 21 W h kg⁻¹ when the specific power increased from 1821 to 6580 W kg⁻¹. Our findings indicate that the dandelion-shaped CoMoO₄ nanostructures can be applied as a promising material for making high performance electrochemical capacitors.