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