Nanosheets of nickel, cobalt and manganese triple hydroxides/oxyhydroxides as efficient electrode materials for asymmetrical supercapacitors

Abstract

Transition metals play a significant role in energy storage applications mainly as electrode materials in supercapacitors. In this work, triple hydroxide/oxyhydroxide nanosheets of a nickel, cobalt and manganese (NCM) composite were electrochemically deposited on carbon cloth (CC) and used as electrode materials in supercapacitors. In a three electrode system the composite delivered a specific capacitance of 707 F g⁻¹ at a current density of 3 A g⁻¹ which retained its stability even at a higher current density of 50 A g⁻¹. An asymmetric supercapacitor (ASC) was assembled and characterized using NCM as the positive electrode, activated carbon as the negative electrode and Whatman filter paper soaked in KOH as the separator. The device operated in a working potential window of 1.75 V and it delivered a power density of 13.12 kW kg⁻¹ and an energy density of 23.7 W h kg⁻¹.