Lithium ion capacitor
AssigneeTaiyo Yuden Co., Ltd.
InventorTakeo Tsuzuki
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Abstract
A lithium ion capacitor has an electrolytic solution that contains: an electrolyte which is a mixture of LiFSI and LiBF4, where the mol ratio of LiFSI to LiBF4 is in a range of 90/10 to 30/70; a solvent that contains at least one type of cyclic or chained carbonate compound; and a film-forming agent; wherein the concentration of electrolyte in the electrolytic solution is in a range of 1.2 to 1.8 mol/L. The lithium ion capacitor can maintain its initial high capacitance and low internal resistance, while also undergoing minimal characteristics changes after exposure to a high-temperature, high-voltage environment.
Claims4
A lithium ion capacitor having an electrolytic solution that contains:
- an electrolyte which is a mixture of LiFSI and LiBF4 which are the only lithium salts used as the electrolyte, where the mol ratio of LiFSI to LiBF4 is in a range of 90/10 to 30/70;
- a solvent that contains at least one cyclic or chained carbonate compound;
- and
- a film-forming agent which suppresses reductive decomposition of the solvent by reductively decomposing itself at a potential higher than that of the solvent, thereby forming a film on a negative electrode;
- wherein a concentration of electrolyte in the electrolytic solution is in a range of 1.2 to 1.8 mol/L.
Dependencies are inferred from the claim text.