ELECTROLYTE SOLUTION AND ELECTROCHEMICAL CAPACITOR USING SAME

摘要

Disclosed is an electrolyte solution which is highly reliable in charging/discharging under high voltage conditions. Also disclosed is an electrochemical capacitor using the electrolyte solution. The electrolyte solution is characterized by containing a solvent, an electrolyte which is represented by the composition formula below and contains anions having a perfluoroalkyl group, and an acid-inducing substance that contains fluorine atoms for anions. The electrolyte solution is also characterized in that the weight ratio of the acid-inducing substance is within the range of 0.0001-2.0 wt%. MX+[Q(Rf)yFz]X- (In the formula, Q represents a group 13 or 15 element of the periodic table; Rf represents a perfluoroalkyl group (CnF2n+1); n represents a natural number; 1 = y X+ represents a monovalent to trivalent cation; and X represents a natural number of 1-3.) Consequently, both an excessive potential decrease due to the electrolyte and breakage of the protective film of the negative electrode by HF can be suppressed, and thus deterioration of cycle characteristics can be suppressed even when charging/discharging is performed under high temperature or high voltage conditions.