Nonaqueous secondary battery
View Patent ↗A positive electrode active material has an average particle diameter of 4.5 to 15.5 μm and a specific surface area of 0.13 to 0.80 m 2 /g. A positive electrode mixture layer contains a silane coupling agent and/or at least one of aluminum, titanium, or zirconium based coupling agent having an alkyl or alkoxy groups having 1 to 18 carbon atoms at a content of 0.003% by mass or more and 5% by mass or less with respect to the mass of the positive electrode active material. The nonaqueous electrolyte contains a fluorinated cyclic carbonate esters at a content of 0.3% by mass or more with respect to the total mass of the nonaqueous electrolyte. Thus the nonaqueous secondary battery in which, when used with a nonaqueous electrolyte containing a fluorinated cyclic carbonate esters, cycle characteristics are good and nail penetration characteristics are superior is provided.
1. A nonaqueous secondary battery comprising:
a positive electrode plate formed with a positive electrode mixture layer having a lithium composite oxide as a positive electrode active material;
a negative electrode plate;
a separator; and
a nonaqueous electrolyte,
the positive electrode active material having an average particle diameter of 4.5 to 15.5 μm and a specific surface area of 0.13 to 0.80 m 2 /g,
the positive electrode mixture layer containing a silane coupling agent, a coupling agent represented by General Formula (I), or a silane coupling agent and a coupling agent represented by General Formula (I), at a content of 0.003% by mass or more and 5% by mass or less with respect to the mass of the positive electrode active material,
(where M is one atom selected from Al, Ti, and Zr, each of R1 and R2 is an alkyl group or an alkoxy group having 1 to 18 carbon atoms, and n represents an integer of 1 to 4), and
the nonaqueous electrolyte containing a fluorinated cyclic carbonate ester represented by General Formula (II) at a content of 0.3% by mass or more with respect to the total mass of the nonaqueous electrolyte:
(where each of X1 to X4 is a fluorine group, an alkyl group, or a fluorinated alkyl group, X1 to X4 are optionally the same as or different from each other, at least one of which is a fluorine group or a fluorinated alkyl group).
2. The nonaqueous secondary battery according to claim 1 , wherein the positive electrode mixture layer contains a coupling agent represented by General Formula (I), where M is Al:
(where each of R1 and R2 is an alkyl group or an alkoxy group having 1 to 18 carbon atoms, and n represents an integer of 1 to 4).
3. The nonaqueous secondary battery according to claim 1 , wherein the positive electrode mixture layer contains a coupling agent represented by General Formula (I), where at least one of R1 and R2 is an alkoxy group:
(where M is one atom selected from Al, Ti, and Zr, each of R1 and R2 is an alkyl group or an alkoxy group having 1 to 18 carbon atoms, and n represents an integer of 1 to 4).
4. The nonaqueous secondary battery according to claim 1 , wherein the nonaqueous electrolyte contains the fluorinated cyclic carbonate ester represented by General Formula (II) at a content of 0.3% by mass or more and 40% by mass or less with respect to the total mass of the nonaqueous electrolyte.
5. The nonaqueous secondary battery according to claim 1 , wherein the fluorinated cyclic carbonate ester is FEC, cis-DFEC or trans-DFEC.
6. The nonaqueous secondary battery according to claim 5 wherein the fluorinated cyclic carbonate ester is FEC.
7. The nonaqueous secondary battery according to claim 1 , wherein the coupling agent represented by General Formula (I) is one selected from the group consisting of aluminum bisethylacetoacetate monoacetylacetonate, aluminum ethylacetoacetate diisopropylate, aluminum triethilacetate, aluminum trisacetylacetonate, titanium bis(ethylacetoacetate), titanium bisethylacetoacetate bisacetylacetonate and zirconium tetrakisacetylacetonate.
8. The nonaqueous secondary battery according to claim 4 , wherein the coupling agent represented by General Formula (I) is aluminum bisethylacetoacetate monoacetylacetonate.