摘要 |
There is provided an electric storage device comprising carbonaceous active material-containing positive and negative electrodes, an onium salt-containing nonaqueous electrolyte, and a separator, wherein an electrochemical charge process in the positive electrode shows a sequential charge process having a threshold of a transition voltage and consisting of an adsorption process of anions of the onium salt in a lower voltage range than the transition voltage and an intercalation process of anions of the onium salt in a higher voltage range than the transition voltage. The electric storage device is advantageous in that the electric storage capacity and energy capacity which can be substantially utilizable are large and, at the same time, a charge/discharge cycle is highly reliable.
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