Non-aqueous electrolytic solution for lithium secondary battery or lithium ion capacitor, and lithium secondary battery or lithium ion capacitor using the same
摘要
說(shuō)明書
In the case where a cyclic carbonate having an unsaturated bond such as a carbon-carbon double bond or a carbon-carbon triple bond and a cyclic carbonate having a fluorine atom(s) are used in combination, the total content of these carbonates is preferably 0.3% by volume or more and more preferably 0.7% by volume or more, in relation to the whole of the non-aqueous solvent. The upper limit of the total content of these carbonates us preferably 7% by volume or less and more preferably 5% by volume or less. The above-described content range more preferably leads to the synergistic effect due to the combined use of the cyclic carbonate having an unsaturated bond and the fluorine atom-containing cyclic carbonate.
When these cyclic carbonates are used in combination of three or more thereof, the improvement effect of the electrochemical characteristics in a high temperature environment is preferably further improved, and the use of these cyclic carbonates in combination of four or more thereof is particularly preferable. As suitable combinations of these cyclic carbonates, for example, the following are preferable: EC, PC and VC; EC, PC and FEC; EC, PC and VEC; EC, PC and EEC; EC, PC, VC and FEC; EC, PC, VC and VEC; EC, PC, VC and EEC; EC, PC, FEC and VEC; EC, PC, FEC and EEC; or EC, PC, VEC and EEC. More preferable among the above-described combinations are, for example, EC, PC and VC; EC, PC and FEC; EC, PC and EEC; EC, PC, VC and FEC, or EC, PC, VC and EEC.
In the non-aqueous electrolytic solution according to the first aspect of the present invention and the non-aqueous electrolytic solution according to the second aspect of the present invention, at least, methyl ethyl carbonate and dimethyl carbonate are used as the chain carbonate.
