Nonaqueous electrolyte secondary battery
One aspect of the present invention provides a nonaqueous electrolyte secondary battery including a sulfur-containing positive electrode, a negative electrode, a cation exchange resin layer interposed between the positive electrode and the negative electrode, a positive electrode electrolyte, and a negative electrode electrolyte. The positive electrode electrolyte contains lithium polysulfide, and a sulfur equivalent concentration of the positive electrode electrolyte is higher than the sulfur equivalent concentration of the negative electrode electrolyte. Another aspect of the present invention provides a nonaqueous electrolyte secondary battery including a sulfur-containing positive electrode, a negative electrode, a cation exchange resin layer interposed between the positive electrode and the negative electrode, and a nonaqueous electrolyte. At least one of the positive electrode and the negative electrode includes a cation exchange resin, and a concentration of an anion contained in the nonaqueous electrolyte is 0.7 mol/l or less.
1. A nonaqueous electrolyte secondary battery comprising:
a sulfur-containing positive electrode;
a negative electrode;
a cation exchange resin layer interposed between the sulfur-containing positive electrode and the negative electrode;
a positive electrode electrolyte; and
a negative electrode electrolyte,
wherein the positive electrode electrolyte contains lithium polysulfide, and a sulfur equivalent concentration of the positive electrode electrolyte is higher than a sulfur equivalent concentration of the negative electrode electrolyte, and
wherein the sulfur equivalent concentration of the positive electrode electrolyte is 1.2 mol/l or more.
2. The nonaqueous electrolyte secondary battery according to claim 1 , wherein the sulfur equivalent concentration of the positive electrode electrolyte is 3.0 mol/l or more.
3. The nonaqueous electrolyte secondary battery according to claim 1 , wherein the sulfur equivalent concentration of the positive electrode electrolyte is 18 mol/l or less.
4. The nonaqueous electrolyte secondary battery according to claim 1 , wherein a concentration of an anion contained in at least one of the positive electrode electrolyte or the negative electrode electrolyte is 0.7 mol/l or less.
5. The nonaqueous electrolyte secondary battery according to claim 1 , wherein a concentration of an anion contained in the positive electrode electrolyte is 0.3 mol/l or less.
6. The nonaqueous electrolyte secondary battery according to claim 1 , wherein the cation exchange resin layer has a first surface having a roughness factor of 3 or more.
7. The nonaqueous electrolyte secondary battery according to claim 6 , wherein the first surface of the cation exchange resin layer has an arithmetic mean roughness Ra of 0.5 μm or more.
8. The nonaqueous electrolyte secondary battery according to claim 6 , wherein the first surface of the cation exchange resin layer has a maximum height roughness Rz of 0.5 μm or more.
9. The nonaqueous electrolyte secondary battery according to claim 6 , further comprising a porous layer, the porous layer being in contact with the first surface of the cation exchange resin layer.
10. A method for producing a nonaqueous electrolyte secondary battery including a sulfur-containing positive electrode, a negative electrode, and a cation exchange resin layer interposed between the sulfur-containing positive electrode and the negative electrode, the method comprising:
injecting a lithium polysulfide-containing positive electrode electrolyte between the sulfur-containing positive electrode and the cation exchange resin layer; and
injecting a negative electrode electrolyte, which has a lithium polysulfide concentration lower than that of the positive electrode electrolyte, between the negative electrode and the cation exchange resin layer.
11. The nonaqueous electrolyte secondary battery according to claim 1 , wherein the sulfur equivalent concentration of the positive electrode electrolyte is 1.5 mol/l or more.