Smart design of free-standing ultrathin Co–Co(OH)2 composite nanoflakes on 3D nickel foam for high-performance electrochemical capacitors

Abstract

Ultrathin Co–Co(OH)₂ composite nanoflakes have been fabricated through electrodeposition on 3D nickel foam. As electrochemical capacitor electrodes, they exhibit a high specific capacitance of 1000 F g⁻¹ at the scan rate of 5 mV s⁻¹ and 980 F g⁻¹ at the current density of 1 A g⁻¹, respectively, and the retention of capacitance is 91% after 5000 cycles.