Lithium-ion secondary battery including polybenzimidazole and method of manufacturing lithium-ion secondary battery

1. A lithium-ion secondary battery comprising:

a positive electrode that comprises:

a current collector;

an active material layer containing an active material and polybenzimidazole; and

an insulating layer; and

a separator positioned on a surface of the active material layer;

wherein:

the insulating layer is formed on a surface of the active material layer that opposes the separator;

polybenzimidazole molecules are directly bonded via hydrogen bonds to other polybenzimidazole molecules in the active material layer;

the polybenzimidazole is present in the active material layer in an amount of 2 to 10 mass % based on a total mass of the active material layer;

the active material is present in the active material layer in an amount of 80 to 98 mass % based on the total mass of the active material layer; and

the active material is selected from the group consisting of: lithium titanate, lithium cobaltate, nickelate, lithium manganese spinel, mixed metal oxide represented by the general formula: LiNi x Co y Mn z M1 a O 2 , lithium vanadium compound, olivine-type LiM2PO 4 , and a combination thereof,

where:

a sum of x, y, z, and a is 1;

x is greater than or equal to 0 and less than or equal to 1;

y is greater than or equal to 0 and less than or equal to 1;

z is greater than or equal to 0 and less than or equal to 1;

a is greater than or equal to 0 and less than or equal to 1;

M1 is at least one element selected from the group consisting of Al, Mg, Nb, Ti, Cu, Zn, and Cr, and

M2 is at least one selected from the group consisting of Co, Ni, Mn, Fe, Mg, Nb, Ti, Al, Zr, and VO.

2. The lithium-ion secondary battery according to claim 1 , wherein a thickness of the insulating layer is from about 1 to 1000 nm.

3. The lithium-ion secondary battery according to claim 1 , wherein the insulating layer includes a material selected from the group consisting of aluminum oxide, zirconium oxide, titanium oxide, silicon oxide, magnesium oxide, zinc oxide, iron oxide, copper oxide, and tin oxide.

4. The lithium-ion secondary battery according to claim 1 , further comprising an electrolytic solution containing lithium ions.

5. A lithium-ion secondary battery comprising:

a negative electrode that comprises:

a current collector; and

an active material layer containing an active material and polybenzimidazole; and

an insulating layer; and

a separator positioned on a surface of the active material layer;

wherein:

the insulating layer is formed on a surface of the active material layer that opposes the separator;

polybenzimidazole molecules are directly bonded via hydrogen bonds to other polybenzimidazole molecules in the active material layer;

the polybenzimidazole is present in the active material layer in an amount of 2 to 10 mass % based on a total mass of the active material layer;

the active material is present in the active material layer in an amount of 80 to 98 mass % based on the total mass of the active material layer; and

the active material is selected from the group consisting of: Si, Si alloy, alloy of Si and Cu, alloy of Si and Ni, alloy of Si and Ti, graphite, Al, Al alloy, Sn, Sn alloy, SiO x , SnO x , lithium titanate, TiO 2 , and a combination thereof,

where x is greater than 1 and less than or equal to 2.

6. The lithium-ion secondary battery according to claim 5 , further comprising an electrolytic solution containing lithium ions.

7. A method of manufacturing a lithium-ion secondary battery comprising:

manufacturing an electrode by:

applying a coating material containing an active material and polybenzimidazole to a current collector, so as to form an active material layer made of the coating material on the current collector; and

forming an insulating layer on a surface of the active material layer; and

providing a separator on a surface of the active material layer; and

wherein:

the insulating layer is formed on the surface of the active material layer that opposes the separator;

polybenzimidazole molecules are directly bonded via hydrogen bonds to other polybenzimidazole molecules in the active material layer;

the polybenzimidazole is present in the active material layer in an amount of 2 to 10 mass % based on a total mass of the active material layer;

the active material is present in the active material layer in an amount of 80 to 98 mass % based on the total mass of the active material layer; and

the active material is selected from the group consisting of: Si, Si alloy, alloy of Si and Cu, alloy of Si and Ni, alloy of Si and Ti, graphite, Al, Al alloy, Sn, Sn alloy, SiO x , SnO x , lithium titanate, TiO 2 , cobaltate, lithium nickelate, lithium manganese spinel, mixed metal oxide represented by the general formula: LiNi q Co y Mn z M1 a O 2 , lithium vanadium compound, olivine-type LiM2PO 4 , and a combination thereof,

where:

x is greater than 1 and less than or equal to 2;

a sum of q, y, z, and a is 1;

q is greater than or equal to 0 and less than or equal to 1;

y is greater than or equal to 0 and less than or equal to 1;

z is greater than or equal to 0 and less than or equal to 1;

a is greater than or equal to 0 and less than or equal to 1;

M1 is at least one element selected from the group consisting of Al, Mg, Nb, Ti, Cu, Zn, and Cr; and

M2 is at least one selected from the group consisting of Co, Ni, Mn, Fe, Mg, Nb, Ti, Al, Zr, and VO.

8. The method of manufacturing a lithium-ion secondary battery according to claim 7 , wherein manufacturing the electrode further comprises heating the active material layer to a temperature of 100 to 430° C.

9. The method of manufacturing a lithium-ion secondary battery according to claim 7 , further comprising heating the active material layer to a temperature of 250 to 430° C.

10. The method according to claim 7 , wherein the lithium-ion secondary battery comprises an electrolytic solution containing lithium ions.