US 8,524,067 B2Granted

Electrochemical method of producing nano-scaled graphene platelets

AssigneeNanotek Instruments, Inc.

InventorsAruna Zhamu, Joan Jang, Bor Z. Jang

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Abstract

A method of producing nano-scaled graphene platelets with an average thickness smaller than 30 nm from a layered graphite material. The method comprises (a) forming a carboxylic acid-intercalated graphite compound by an electrochemical reaction; (b) exposing the intercalated graphite compound to a thermal shock to produce exfoliated graphite; and (c) subjecting the exfoliated graphite to a mechanical shearing treatment to produce the nano-scaled graphene platelets. Preferred carboxylic acids are formic acid and acetic acid. The exfoliation step in the instant invention does not involve the evolution of undesirable species, such as NOx and SOx, which are common by-products of exfoliating conventional sulfuric or nitric acid-intercalated graphite compounds. The nano-scaled platelets are candidate reinforcement fillers for polymer nanocomposites. Nano-scaled graphene platelets are much lower-cost alternatives to carbon nano-tubes or carbon nano-fibers.

Claims9

Dependent claims

A method of producing ultra-thin, nano-scaled graphene platelets with an average thickness smaller than 2 nm or 5 graphene sheets from a layered graphite material, said method comprising:

a) forming a carboxylic acid-intercalated graphite compound by an electrochemical reaction which uses a carboxylic acid or derivative as both an electrolyte and an intercalate source, said layered graphite material as an anode material, and a metal or graphite as a cathode material, and wherein a current is imposed upon said cathode and said anode at a current density for a duration of time sufficient for effecting said electrochemical reaction;
b) rapidly heating said carboxylic acid-intercalated graphite compound to a desired temperature to produce exfoliated graphite;
c) re-intercalating said exfoliated graphite by repeating step (a) using said exfoliated graphite as an anode material to form a further carboxylic acid-intercalated graphite compound;
d) rapidly heating said further carboxylic-intercalated graphite compound;
e) subjecting a graphite compound obtained in step (d) to a mechanical shearing treatment to produce said ultra-thin, nano-scaled graphene platelets with an average thickness smaller than 2 nm or 5 graphene sheets;
and
f) recovering said graphene platelets with an average thickness smaller than 2 nm or 5 graphene sheets.

4 more elements

Dependencies are inferred from the claim text.