▎ 摘　　要

NOVELTY - Composition comprises: (i) nickel-cobalt-sulfide (NCS) (I); (ii) carbon based material comprising high surface area activated carbon or reduced graphene oxide (rGO) or functionalized carbon nitride (g-CN) in the ratio of 1-50% (NCS), 50-99% (carbon based material) as anodic composite; and together with (iii) an electrolyte of molten imidazolium salt (II). USE - The composition is useful: for energy storage device; and as energy supply/capture devices for wide range of electrical and electronic devices (claimed). ADVANTAGE - The composition improves the capacitance and cyclic stability of the energy storage device (claimed). DETAILED DESCRIPTION - Composition comprises: (i) nickel-cobalt-sulfide of formula (NCS) (NixCoySz) (I); (ii) carbon based material comprising high surface area activated carbon or reduced graphene oxide (rGO) or functionalized carbon nitride (g-CN) in the ratio of 1-50% (NCS), 50-99% (carbon based material) as anodic composite; and together with (iii) an electrolyte of molten imidazolium salt of formula (II). x = 1 or 2; y = 1, 2 or 4; z = 4 or 8, where y is greater than x; R1-R5 = H, 1-6C alkyl; and X1 = anion of the group comprising tetrafluoroborate, triflate, bis(trifluoromethylsulfonyl)imide, hexafluorophosphate or bis(fluorosulfonyl)imide. An INDEPENDENT CLAIM is also included for an energy storage device with improved cyclic stability and capacitance comprising an anode coated with anodic composite consisting (I), a cathode coated with carbonaceous material comprising mesoporous carbon or activated carbon, a separator, and the electrolyte of molten imidazolium salt of (II).