Ultrathin porous nickel–cobalt hydroxide nanosheets for high-performance supercapacitor electrodes

Abstract

In this work, ultrathin porous nickel–cobalt layered double hydroxide (Ni–Co LDH) hybrid nanosheets on metal nickel sheets are synthesized via a facile hydrothermal method without any adscititious surfactant. The fabricated Ni–Co LDH hybrid nanosheet-based electrodes for supercapacitors in aqueous electrolyte exhibit a significantly enhanced specific capacitance (2184 F g⁻¹ at 1 A g⁻¹) and energy density (91.76 W h kg⁻¹ at 825.84 W kg⁻¹) due to the pronounced synergistic effect between Ni²⁺ and Co²⁺. Meanwhile, the Ni–Co LDH hybrid nanosheets as electrode materials have excellent long-life cycling stability, retaining 88.5% of the initial capacitance after 2000 cycles. Thereby, the Ni–Co nanocomposites are promising electrode materials for high-energy-density long-life cycling supercapacitors.