# US 12,000,055 B2 · Electrochemical conversion of a carbon material to graphene

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- Number: US 12,000,055 B2
- Document ID: US12000055B2
- Status: Granted
- Kind: B2
- Application number: 18/021,906
- Filed: 2021-07-29
- Published: 2024-01-04
- Granted: 2024-06-04
- Earliest claimed: 2020-08-17
- Assignees: Petroliam Nasional Berhad (Petronas)
- Applicants: Petroliam Nasional Berhad (Petronas)
- Inventors: Norariza Ahmad; Zulkifli Ahamid; Muzdalifah Zakaria; Mark Bissett; Ian Kinloch
- Web page: https://patentgrep.com/patent/US12000055B2

## CPC

- C25B 1/135: Carbon
- C01B 32/184: Preparation
- C25B 1/50: Processes
- C25B 9/09: Fused bath cells
- C25B 11/043: Carbon, e.g. diamond or graphene
- C25B 11/061: Metal or alloy
- C01B 2204/30: Purity
- C25B: ELECTROLYTIC OR ELECTROPHORETIC PROCESSES FOR THE PRODUCTION OF COMPOUNDS OR NON-METALS; APPARATUS THEREFOR (anodic or cathodic protection C23F13/00; single-crystal growth C30B)
- C01B: NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; {METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C}

## Abstract

Disclosed herein is a method of converting a carbon material to graphene, the method comprising the step of subjecting an amorphous carbon material pellet submerged in a molten inorganic material that comprises an alkaline earth halide to an electrochemical reaction in an inert atmosphere for a period of time, wherein the amorphous carbon material pellet is converted to a graphene pellet comprising graphene flakes by said reaction.

## Claims

### Claim 1

A method of converting a carbon material to graphene, the method comprising the step of subjecting an amorphous carbon material pellet submerged in a molten inorganic material that comprises an alkaline earth halide to an electrochemical reaction in an inert atmosphere for a period of time, wherein the amorphous carbon material pellet is converted to a graphene pellet comprising graphene flakes by said reaction.

### Claim 2 (depends on 1)

The method according to claim 1, wherein the pellet is broken up to provide individual and/or aggregates of graphene flakes.

### Claim 3 (depends on 2)

The method according to claim 2, wherein the graphene flakes display one or more of the following properties:
(a) at least 70% of the graphene flakes have a thickness of five layers of less;
(b) the thickness of the graphene flakes is from 0.3 to 3 nm;
(c) the lateral size of the graphene flakes is from 500 to 1000 nm.

### Claim 4 (depends on 1)

The method according to claim 1 wherein the molten inorganic material is maintained in a molten state at a temperature of from 700 to 900° C.

### Claim 5 (depends on 4)

The method according to claim 4, wherein the molten inorganic material is maintained in a molten state at a temperature of 850° C.

### Claim 6 (depends on 1)

The method according to claim 1, wherein the alkaline earth halide has formula I:
MX2 I
where M is selected from Ca, Mg and Ba and
X is selected from Cl or Br.

### Claim 7 (depends on 6)

The method according to claim 6, wherein the alkaline earth halide is CaCl2.

### Claim 8 (depends on 1)

The method according to claim 1, wherein the molten inorganic material consists essentially of an alkaline earth halide.

### Claim 9 (depends on 1)

The method according to claim 1, wherein the molten inorganic material further comprises an alkali halide of formula II:
NX
where N is K, Na or Li; and
X is Cl or Br.

### Claim 10 (depends on 9)

The method according to claim 9, wherein, when present, the molar ratio of the alkali halide to the alkaline earth halide is from 0.1:1 to 1:0.1.

### Claim 11 (depends on 1)

The method according to claim 1, wherein the electrochemical reaction is conducted using a voltage of from 2.2 to 3.0 V.

### Claim 12 (depends on 1)

The method according to claim 1, wherein the period of time is from 60 to 120 minutes.

### Claim 13 (depends on 1)

The method according to claim 1, wherein the amorphous carbon is selected from one or more of the group consisting of biomass, coal, activated carbon, coke, and carbon black.

### Claim 14 (depends on 13)

The method according to claim 13, wherein the amorphous carbon is petroleum coke.

### Claim 15 (depends on 1)

The method according to claim 1, wherein the amorphous carbon is provided as a pellet formed by the compression of amorphous carbon particles having an average particle size of from 50 to 100 μm in size.

### Claim 16 (depends on 1)

The method according to claim 1, wherein the inert atmosphere is argon.

### Claim 17 (depends on 1)

The method according to claim 1, wherein the amorphous carbon forms a cathode used in the electrochemical reaction.

### Claim 18 (depends on 17)

The method according to claim 17, wherein the cathode is attached to a current collector, optionally wherein the current collector is formed from one or more of a molybdenum mesh, a molybdenum wire and a nickel foam.

### Claim 19 (depends on 17)

The method according to claim 17, where an anode is provided as a counter electrode to the cathode.

### Claim 20 (depends on 19)

The method according to claim 19, wherein the anode is formed from graphite.