TECHNOLOGY FOCUS - ORGANIC CHEMISTRY - Preferred Properties: The thickness of negative-side recessed impregnated area is 10-40% of the thickness of the positive-side recessed impregnated area. The BET specific surface areas of the solid particles is 1-60 m2/g. Preferred Composition: The electrolyte solution contains nonaqueous solvent including 30 %mass or more cyclic alkylene carbonate. The content of solid particles in at least one deep region is 3 vol.% or less. The solid particles are inorganic particles and/or organic particles. The electrolyte solution is nonaqueous electrolyte comprising unsaturated cyclic carbonate ester of formula (I) and halogenated carbonate ester of formula (II) and formula (III), nonaqueous electrolyte comprising sulfinyl compounds of formulae: R'1-OS(=O)-O-R'2, R'3-O-S(=O)(=O)-R'4, R'5-S(=O)(=O)-R'6, R'7-S(=O)(=O)-O-S(=O)(=O)-R'8, R'9-S(=O)(=O)-R15-S(=O)(=O)-O-R'14 or R'16-S(=O)(=O)-R'18-O-S(=O)(=O)-R'17, or sulfonyl compound, nonaqueous electrolyte containing aromatic compound of formulae (1B)-(4B), nonaqueous electrolyte comprising dinitrile compound of formula: NC-R61-CN, nonaqueous electrolyte comprising 7 metal salt compounds e.g. salt of formula (1D).X=-C(=R1)-C(=R2)-, -C(=R1)-C(=R2)-C(=R3)-, -C(=R1)-C(R4)(R5)-, -C(=R1)-C(R4)(R5)-C(R6)(R7)-, -C(R4)(R5)-C(=R1)-C(R6)(R7)-, -C(=R1)-C(=R2)-C(R4)(R5)-, -C(=R1)-C(R4)(R5)-C(=R2)-, -C(=R1)-O-C(R4)(R5)-, -C(=R1)-O-C(=R2)-, -C(=R1)-C(=R8)-, -C(=R1)-C(=R2)-C(=R8)-;R1-R3=bivalent hydrocarbyl or bivalent halogenated hydrocarbyl;R4-R7=monovalent hydrogen group (-H), 1-8C monovalent hydrocarbyl, 1-6C monovalent hydrocarbyl or 1-6C monovalent hydrocarbyl;R8=5 or less 2-5C halogenated hydrocarbyl or 2C or more halogenated alkylene;R21-R24=H, halo, alkyl, or haloalkyl, where at least one of R21-R24 is halo or haloalkyl;R25-R30=H, halo, alkyl, or haloalkyl, where at least one of R25-R30 is halo or haloalkyl;R'1-R'14,R'16,R'17=monovalent hydrocarbyl or monovalent halogenated hydrocarbyl;R'15,R'18,R61=R1, where two or more of R'1-R'12, R'13-R'15 or R'16-R'18;X31=group 2 element of periodic table or Al;M31,M41=transition metal or group 13 element, group 14 element or group 15 element of periodic table;R71=halo;Y31=-C(=O)-R72-C(=O)-, -C(=O)-C(R73)2- or -C(=O)-C(=O)-;R31-R45=not defined;R72=alkylene, haloalkylene, arylene, or haloarylene;R73=alkyl, haloalkyl, aryl, or haloaryl;a3=1-4;b3=0, 2 or 4;andc3,d3,m3,n3=1-3.N.B. R31-R45 are not defined.