Enhanced pseudocapacitance of NiSe2/Ni(OH)2 nanocomposites for supercapacitor electrode

Abstract We report a novel NiSe2/Ni(OH)2 nanocomposites (NNCs) synthesized using a facile hydrothermal method followed by ultrasonication and employed it as an electrode for supercapacitor. The structural and compositional analysis confirmed the presence of NiSe2 and Ni(OH)2 in the synthesized NNCs. The NNCs electrodes delivered an ultrahigh specific capacitance (2212 F g−1) than pristine NiSe2 (326 F g−1) at a current density of 2 mA cm−2 with capacitance retention of 95% after 5000 cycles. The enhanced performance is due to the positive synergetic effect between NiSe2 and Ni(OH)2, which provides a free diffusion pathway for the fast ion transport and facile ion accessibility to storage sites.