CuCo<sub>2</sub>O<sub>4</sub> Nanorods Coated with CuO Nanoneedles for Supercapacitor Applications
Gokul P. Kamble, Akash S. Rasal, Samadhan B. Gaikwad, Vivek Gurav, Jia‐Yaw Chang, Sanjay S. Kolekar, Yong‐Chien Ling, Anil V. Ghule
Abstract
Herein, we report the chemical synthesis of a core–shell nanoarchitecture comprising CuCo2O4@CuO (CCO@CuO) on a flexible stainless steel mesh substrate (FSSM) with CuCo2O4 (core) and CuO (shell) by a simple, cost-efficient, additive-free hydrothermal deposition method, followed by successive ionic layer adsorption and reaction method for fabricating a flexible electrode for an asymmetric supercapacitor (ASC). The nanocomposite of CCO@CuO revealed a high surface area of 98.33 m2 g–1 and the electrode delivered a high specific capacitance of 713 F g–1 at a high current density of 11 mA cm–2, which was noted to be higher than those of the individual constituent CuO (436 F g–1) and CuCo2O4 (443 F g–1) metal oxide electrodes. The CCO@CuO electrode demonstrated remarkable cycling stability (∼90% capacitance retention after 5000 charge–discharge cycles at 15 mA cm–2). The ASC device CCO@CuO//rGO (reduced graphene oxide) delivered a maximum energy density of 37.43 Wh kg–1 at a power density of 250 W kg–1. The device revealed 83% capacitance retention after 4000 cycles. These results indicate that the CCO@CuO/FSSM electrode is a promising functional material for energy storage devices.