Positive temperature coefficient film, positive temperature coefficient electrode, positive temperature coefficient separator, and battery comprising the same
Provided herein is a positive temperature coefficient film comprising an inorganic positive temperature coefficient compound. Also provided herein are a positive temperature coefficient electrode, a positive temperature coefficient separator, and a positive temperature coefficient lithium secondary battery, each of which comprises the positive temperature coefficient film.
1. A battery electrode, comprising:
a first electroactive layer comprising an electroactive material; and
a first positive temperature coefficient (PTC) film disposed on one side of the electroactive layer, the first PTC film comprising barium titanate and a polyamide-imide.
2. The battery electrode of claim 1 , wherein the barium titanate is in the form of nanoparticles.
3. The battery electrode of claim 1 , wherein the polyamide-imide is formed in the presence of barium titanate.
4. The battery electrode of claim 1 , wherein the first PTC film further comprises a polyimide.
5. The PTC film of claim 4 , wherein the crosslinked polymer is a polypropylene.
6. The battery electrode of claim 1 , wherein the first PTC film comprises no less than about 50% by weight of barium titanate and no greater than about 50% by weight of the polyamide-imide.
7. The battery electrode of claim 6 , wherein the first PTC film comprises no less than about 70% by weight of barium titanate and no greater than about 30% by weight of the polyamide-imide.
8. The battery electrode of claim 1 , wherein the first PTC film further comprises a conductive material.
9. The battery electrode of claim 8 , wherein the conductive material is carbon black.
10. The battery electrode of claim 8 , wherein the first PTC film comprises no less than about 50% by weight of barium titanate, no greater than about 50% by weight of the polyamide-imide, and no greater than about 5% by weight of the conductive material.
11. The battery electrode of claim 10 , wherein the first PTC film comprises no less than about 70% by weight of barium titanate, no greater than about 30% by weight of the polyamide-imide, and no greater than about 2% by weight of the conductive material.
12. The battery electrode of claim 1 , wherein the first PTC film further comprises a filler.
13. The battery electrode of claim 12 , wherein the filler is a polymer.
14. The battery electrode of claim 12 , wherein the filler is polyvinylidene fluoride or styrene butadiene rubber.
15. The battery electrode of claim 12 , wherein the first PTC film comprises no less than about 50% by weight of barium titanate, no greater than about 50% by weight of the polyamide-imide, no greater than about 5% by weight of the conductive material, and no greater than about 10% by weight of the filler.
16. The battery electrode of claim 15 , wherein the first PTC film comprises no less than about 70% by weight of barium titanate, no greater than about 30% by weight of the polyamide-imide, no greater than about 2% by weight of the conductive material, and no greater than about 10% by weight of the filler.
17. The battery electrode of claim 1 , wherein the first PTC film comprises no less than about 70% by weight of barium titanate, no greater than about 30% by weight of the polyamide-imide, and no greater than about 2% of carbon black.
18. The PTC film of claim 1 , comprising no less than about 70% by weight of barium titanate, no greater than about 30% of a polypropylene, no greater than about 2% of carbon black, and no greater than about 10% of polyvinylidene fluoride.
19. The PTC film of claim 1 , comprising no less than about 70% by weight of barium titanate, no greater than about 30% by weight of a polypropylene, and no greater than about 10% by weight of polyvinylidene fluoride.
20. The PTC film of claim 1 , comprising no less than about 70% by weight of barium titanate, no greater than about 30% by weight of carboxymethyl cellulose, no greater than 2% by weight of carbon black, and no greater than about 10% by weight of styrene butadiene rubber.
21. The battery electrode of claim 1 , wherein the first PTC film is formed by crosslinking a precursor of the polyamide-imide in the presence of barium titanate.
22. The battery electrode of claim 1 , wherein the first PTC film is formed using water as a solvent.
23. The battery electrode of claim 1 , further comprising: a current collector, a second electroactive layer, and a second PTC film wherein the first PTC film or the second PTC film is disposed on one side of the current collector such that at least one PTC film is in direct contact with the current collector, and wherein first electroactive layer or the second electroactive layer is interposed between the first PTC film and the second PTC film such that no PTC film is direct contact with another PTC film.
24. The battery electrode of claim 23 , wherein the first electroactive or the second electroactive layer is in direct contact with the current collector.
25. A lithium secondary battery comprising:
an anode;
a cathode;
a separator; and
electrolyte, wherein the anode and/or the cathode comprises the battery electrode of claim 1 .
26. The battery electrode of claim 1 , further comprising a fire-retardant material, wherein the fire retardant material comprises an inorganic material adapted to release carbon dioxide; a borate; and/or an organophosphate.
27. The battery electrode of claim 23 , wherein the battery electrode includes a same number of PTC films as electroactive layers.