# US 12,191,522 B2 · Porous polybenzimidazole as separator for lithium ion batteries

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- Number: US 12,191,522 B2
- Document ID: US12191522B2
- Status: Granted
- Kind: B2
- Application number: 16/490,851
- Filed: 2018-03-05
- Published: 2019-12-19
- Granted: 2025-01-07
- Earliest claimed: 2017-03-06
- Assignees: Council of Scientific and Industrial Research
- Applicants: Council of Scientific and Industrial Research
- Inventors: Vikas Kumar; Swaminathan Sivaram; Ver Avadhani Chilukuri
- Web page: https://patentgrep.com/patent/US12191522B2

## CPC

- H01M 50/446: Composite material consisting of a mixture of organic and inorganic materials
- C08G 73/18: Polybenzimidazoles
- C08K 3/26: Carbonates; Bicarbonates
- C08K 3/36: Silica
- H01M 10/0525: Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodes; Lithium-ion batteries
- C08K 2003/265: {Calcium, strontium or barium carbonate}
- C08L 33/24: Homopolymers or copolymers of amides or imides
- C08L 2203/16: used for films
- C08L 2203/20: use in electrical or conductive gadgets
- H01M 50/40: Separators; Membranes; Diaphragms; Spacing elements inside cells
- H01M 50/414: Synthetic resins, e.g. thermoplastics or thermosetting resins
- H01M 50/489: Separators, membranes, diaphragms or spacing elements inside the cells, characterised by their physical properties, e.g. swelling degree, hydrophilicity or shut down properties
- H01M 50/497: Ionic conductivity
- Y02E 60/10: Energy storage using batteries
- H01M: PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- C08G: MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
- C08K: Use of inorganic or non-macromolecular organic substances as compounding ingredients (paints, inks, varnishes, dyes, polishes, adhesives C09)
- C08L: COMPOSITIONS OF MACROMOLECULAR COMPOUNDS (compositions based on polymerisable monomers C08F, C08G; artificial filaments or fibres D01F; textile treating compositions D06)
- Y02E: REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION

## Abstract

The present invention discloses a film comprising porous, amorphous polybenzimidazole (PBI) and at least one filler for use as a separator in a lithium ion battery and a process for preparation thereof.

## Claims

### Claim 1

A porous film comprising amorphous polybenzimidazole and at least one filler for use as a separator in a lithium ion battery, wherein the amount of filler is in the range of 0.5 wt % to 5.0 wt % of the amorphous polybenzimidazole, wherein said filler consists of silica, calcium carbonate, or a combination thereof, wherein the porous film has a melt integrity up to a temperature of 375° C., and wherein the porous film is standalone and is free of a coating and a support.

### Claim 2 (depends on 1)

The porous film of claim 1, wherein said amorphous polybenzimidazole is selected from the group consisting of poly(2,2′-(m-phenylene)-5,5′-bisbenzimidazole) and poly (2,5-benzimidazole).

### Claim 3 (depends on 1)

The porous film of claim 1, wherein the film has a thickness of about 50 microns.

### Claim 4 (depends on 1)

The porous film of claim 1, wherein the film has a conductivity in the range of 0.4 to 1.0 mS/cm.

### Claim 5 (depends on 1)

The porous film of claim 1, wherein the film has a bulk resistance in the range of 4-8 ohms.

### Claim 6 (depends on 1)

The porous film of claim 1, wherein the film comprises pores formed around particles of the filler.

### Claim 7 (depends on 6)

The porous film of claim 6, wherein the filler is silica, and wherein the particles of the filler have a size between 0.01 and 0.02 mm.

### Claim 8 (depends on 1)

The porous film of claim 1, wherein the porous film has a glass transition temperature between 420 and 450° C.

### Claim 9

A process for manufacturing a porous film for use as a separator in a lithium ion battery, the process comprising:
(a) preparing a polybenzimidazole solution in a solvent followed by heating the polybenzimidazole solution to a temperature ranging from 90° C. to 100° C. and stirring for a time ranging from 16-20 h;
(b) adding a filler into the polybenzimidazole solution of step (a); and
(c) casting a resultant solution on a glass plate to afford the porous film,
wherein the porous film comprises amorphous polybenzimidazole and the filler,
wherein the filler consists of silica, calcium carbonate, or a combination thereof,
wherein an amount of the filler in the porous film is in the range of 0.5 wt % to 5.0 wt % of the amorphous polybenzimidazole,
wherein the porous film has a melt integrity up to a temperature of 375° C., and
wherein the porous film is standalone and is free of a coating and a support.

### Claim 10 (depends on 9)

The process of claim 9, wherein the amorphous polybenzimidazole is selected from the group consisting of poly(2,2′-(m-phenylene)-5,5′-bisbenzimidazole) and poly (2, 5-benzimidazole).

### Claim 11 (depends on 9)

The process of claim 9, wherein the solvent of step (a) is selected from the group consisting of N-methyl-2-pyrrolidone, N, N-dimethyl acetamide, N, N-dimethyl formamide, dimethyl sulfoxide, trifluoroacetic acid and mixtures thereof.