Negative electrode for power storage device, method for forming the same, and power storage device
An object is to suppress electrochemical decomposition of an electrolyte solution and the like at a negative electrode in a lithium ion battery or a lithium ion capacitor; thus, irreversible capacity is reduced, cycle performance is improved, or operating temperature range is extended. A negative electrode for a power storage device including a negative electrode current collector, a negative electrode active material layer which is over the negative electrode current collector and includes a plurality of particles of a negative electrode active material, and a film covering part of the negative electrode active material. The film has an insulating property and lithium ion conductivity.
1. A battery comprising:
a plurality of laminated bodies enveloped in an exterior body, each of the plurality of laminated bodies comprising a sheet-shaped positive electrode and a sheet-shaped negative electrode with a sheet-shaped separator interposed therebetween,
wherein at least one of the sheet-shaped negative electrodes comprises:
a current collector; and
an active material layer including a graphite particle and acetylene black,
wherein the graphite particle is partly covered by an insulating film having a conductivity of a carrier ion,
wherein the graphite particle has concavo-convex shape,
wherein a concave portion of the graphite particle is covered by the insulating film, and
wherein the current collectors of the sheet-shaped negative electrodes each have a tab region extending outside from the exterior body.
2. The battery according to claim 1 , wherein the insulating film comprises Nb 2 O 5 .
3. The battery according to claim 1 , wherein the insulating film comprises silicon oxide.
4. The battery according to claim 1 , wherein the carrier ion is a lithium ion.
5. The battery according to claim 1 , wherein the insulating film has a thickness of more than or equal to 5 nm and less than or equal to 50 nm.
6. The battery according to claim 1 , wherein the battery is flexible.
7. The battery according to claim 1 , wherein the battery is configured so that each of the plurality of laminated bodies is able to wholly exist in a planar shape in the exterior body.
8. The battery according to claim 1 , wherein the exterior body comprises:
a flexible metal thin film; and
an insulating resin film over the flexible metal thin film, and
wherein an inner surface of the exterior body comprises one of materials selected from a polyethylene, a polypropylene, a polycarbonate, an ionomer, and a polyamide.