Method of improving aqueous dispersibility of conductive carbon powder, and method of preparing colloid solution of conductive carbon powder

A method for treating a conductive carbon powder, the method comprising:

• (a) subjecting a gas having 100% carbon dioxide (CO2) to a plasma reactor to obtain a plasma-treated reaction gas;
• and
• (b) injecting the plasma-treated reaction gas from (a) into a reaction container comprising the conductive carbon powder to obtain a treated carbon powder,
• wherein the plasma reactor and the reaction container are separated such that the conductive carbon powder is not exposed to the plasma reactor in (a),
• wherein the treated carbon powder has increased water dispersibility when compared with the conductive carbon powder, and
• wherein the plasma-treated reaction gas comprises carbon monoxide (CO) and carbon trioxide (CO3) radicals.