Electrochemical device

An electrochemical device, comprising a poly(ionic liquid)-modified graphene comprising having graphene and an ionic liquid polymer,

• wherein the ionic liquid polymer comprises either of or both of a following cation and a following anion:
• the cation selected from the group consisting of the following formulae:
• wherein R1 to R10 are each independently any one selected from among i) hydrogen, ii) halogen, and iii) C1-C25 alkyl, alkenyl, alkynyl, benzyl, and phenyl, which may contain a heterogeneous element including O, N, Si and/or S, and may optionally contain Cl, Br, F, I, OH, NH2 and/or SH;
• and
• the anion selected from among [CH3CO2]−, [HSO4]−, [CH3OSO3]−, [C2H5OSO3]−, [AlCl4]−, [CO3]2−, [HCO3]−, [NO2]−, [NO3]−, [SO4]2−, [PO4]3−, [HPO4]2−, [H2PO4]−, [HSO3]−, [CuCl2]−, Cl−, Br−, I−, [BF4]−, [PF6]−, [SbF6]−, [CF3SO3]−, [HCF2CF2SO3]−, [CF3HFCCF2SO3]−, [HCClFCF2SO3]−, [(CF3SO2)2N]−, [(CF3CF2SO2)2N]−, [(CF3SO2)3C]−, [CF3CO2]−, [CF3OCFHCF2SO3]−, [CF3CF2OCFHCF2SO3]−, and [CF3CFHOCF2CF2SO3]−.