Hybrid Aqueous Energy Storage Cells Using Activated Carbon and Lithium-Ion Intercalated Compounds

The polymer gel electrolyte using polyacrylamide and aqueous solution was prepared to study the applicability of polymer gel electrolyte to the activated carbon (AC)/lithium intercalated compound hybrid supercapacitors. The polymer gel electrolyte was found to have high conductivity, which even exceeded that of the aqueous solution counterpart, and wide stable potential window. A supercapacitor consisting of positive and AC negative electrodes using the polymer gel electrolyte was assembled and its charge-discharge profile at various temperatures was investigated and compared to that of a similar hybrid supercapacitor based on aqueous solution electrolyte. Moreover, the effects of polymer gel electrolyte on the capacitance profile, rate capability, self-discharge rate, leakage current, and cycle ability of the hybrid supercapacitor were intensively investigated.