Energy storage properties of hydrothermally processed ultrathin 2D binder-free ZnCo <sub>2</sub> O <sub>4</sub> nanosheets
Muhammad Sufyan Javed, Iftikhar Hussain, Saima Batool, Sajid Hussain Siyal, Tayyaba Najam, Syed Shoaib Ahmad Shah, Muhammad Imran, Mohammad A. Assiri, Shahid Hussain
Abstract
Abstract High energy-density supercapacitors (SCs) with long operating life, cost-effective, and competitive cycling performance is attracted great research attention to competing in the requirements of the modern age. However, despite these benefits, SC hampers inadequate rate-capability and structural deterioration, which primarily affects its commercialization. Herein, ultra-thin two-dimensional (2D) ZnCo 2 O 4 nanosheets are in situ anchored on the conductive surface of nickel foam (denoted as ZCO@NF) by hydrothermal process. The binder-free ZCO@NF is employed as an electrode for SCs and shows impressive charge storage properties. ZCO@NF electrode exhibited a high capacitance of 1250 (750) and 733 F g −1 (440 C g −1 ) at 2.5 and 20 A g −1 , respectively, demonstrating the outstanding rate-capability of 58.6% even at 8 times larger current density. Furthermore, the ZCO@NF electrode exhibits admirable capacitance retention of 96.5% after 10 000 cycles. This impressive performance of the ZCO@NF electrode is attributed to the high surface area which gives a short distance for ion/electron transfer, a high conductivity with extensive electroactive cities, and strong structural stability. The binder-free approach provides a strong relationship between the current collector and the active material, which turns into improved electrochemical operation as an electrode material for SCs.