Application of Graphene Synthesized via Thermal Plasma Methane Pyrolysis as a Conductive Additive in Lithium-Ion Batteries

In this study, methane (CH 4 ), a greenhouse gas (GHG), was converted into graphene through thermal plasma pyrolysis, and its electrochemical performance was evaluated when applied as a conductive additive in lithium-ion battery anodes.CH 4 pyrolysis using a triple plasma torch system with 30 kW input power achieved a CH 4 conversion of 99.48 % and a hydrogen selectivity of 84.65 %.The synthesized graphene exhibited superior crystallinity compared to the commercial conductive additive Super-P, as confirmed by X-ray diffraction and Raman analysis, with an I D /I G ratio of 0.46.Electrical conductivity was 3.15 10 3 S/m, higher than Super-P, and the specific surface area was 158 m 2 /g, more than twice that of Super-P.Battery performance evaluation showed that electrodes with a 1:1 mixing ratio of Super-P and graphene recorded the best performance with a discharge capacity of 286 mAh/g at the 50th cycle.When graphene content exceeded 75 %, capacity decreased sharply due to nanosheet aggregation, which was also confirmed through electrochemical impedance analysis.This study experimentally demonstrated that graphene synthesized via CH 4 pyrolysis has practical applicability as a battery conductive additive and represents a process capable of simultaneously achieving GHG reduction and high-value-added material production.