Abstract: A nonaqueous electrolytic solution having an electrolyte salt dissolved in a nonaqueous solvent, containing a compound of formula (X): where R10 and R20 are each a group selected from an alkyl having 1 to 8 carbon atoms, an alkenyl having 2 to 6 carbon atoms, an alkynyl having 3 to 6 carbon atoms, and an aryl having 6 to 12 carbon atoms, or a lithium; and X is a polar group (i) containing a —C(?O), a —P(?O), or an —S(?O)2 group, a polar group (ii) containing a —CN or an alkyl group having 1 to 6 carbon atoms, in which a part of hydrogen atoms is substituted with a fluorine atom, or a 4- to 7-membered ring polar group (iii) containing a —C(?O)—O— or a —C(?O)—N— group, where when X is a 4- to 7-membered ring polar group (iii) containing —C(?O)—N—, at least one of R10 and R20 is lithium.

Abstract: The present invention is concerned with a nonaqueous electrolytic solution having an electrolyte salt dissolved in a nonaqueous solvent, the nonaqueous electrolytic solution containing a compound represented by the following general formula (X), in which a polar group (X) is bound to a phosphorus atom (P), and capable of improving electrochemical characteristics in a broad temperature range; an energy storage device using the same; and a novel compound.

Abstract: A nonaqueous electrolytic solution of an electrolyte salt dissolved in a nonaqueous solvent, which contains a carboxylate represented by the following general formula (8) in an amount of from 0.01 to 5% by mass of the nonaqueous electrolytic solution: wherein X31 represents -A2-C?Y2, -A2-C(?O)O-A3-C?Y2 or -A2-C(?O)O-A4; A1, A2 and A3 each independently represent an alkylene group having from 1 to 6 carbon atoms; A4 represents an alkyl group having from 1 to 6 carbon atoms; Y1 and Y2 each independently represent CH or N.

Abstract: Disclosed are a nonaqueous electrolytic solution of an electrolyte dissolved in a nonaqueous solvent, which contains a carboxylate represented by the following general formula (I) in an amount of from 0.01 to 10% by mass of the nonaqueous electrolytic solution; and an electrochemical element using it.