Abstract: An electric double layer capacitor which includes a polarization electrode and an electrolyte capable of forming an electric double layer on the surface of the polarization electrode, wherein the solvent in the electrolyte is an organic type mixed solvent containing sulfolane or a sulfolane derivative, and a chain carbonic acid ester represented by the general formula R.sup.1 O(CO)OR.sup.2 (wherein R.sup.1 and R.sup.2, which may be the same or different, are monovalent organic groups).

Abstract: There is disclosed a secondary battery having a negative electrode composed of an active substance and a carrier carrying the active substance, which comprises(1) the active substance is lithium or an alkali metal mainly composed of lithium,(2) the carrier is a mixture composed of(a) a carbonaceous material having(i) an atomic ratio of hydrogen/carbon of less than 0.15 and(ii) a spacing of (002) planes (d.sub.002) as determined by X-ray wide angle diffraction of 3.37 .ANG. or more and a crystallite size in the direction of c axis of 150 .ANG. or less, and(b) a metal capable of forming an alloy with the active substance and/or an alloy with the active substance.