CoNiSe2 nanorods directly grown on Ni foam as advanced cathodes for asymmetric supercapacitors

It is due to their high electrical conductivity and variable valences that transition metal selenides recently emerge as a new class of active materials in batteries, water splitting, fuel cells, solar cells and supercapacitors. In this study, CoNiSe2 nanorods, a binder-free electrode material for pseudocapacitors, are directly synthesized on Ni foam via simple solvothermal method. CoNiSe2 exhibits an area capacity of 1.4 mAh cm−2 at a current density of 3 mA cm−2, which is superior to many advanced previous Ni/Co electrodes. In a two-electrode asymmetric supercapacitor, its energy density reaches 50.66 W h kg−1 a power density of 160.12 W kg−1. When power density increases to 4275.55 W kg−1, energy density still remains at 36.82 W h kg−1. Its low cost of manufacturing and high capacity make CoNiSe2 nanorods a promising electrochemically active material for practical energy storage applications.