▎ 摘　　要

Graphene is one of the most attractive materials because of its outstanding properties. Here we report a straightforward and environmentally friendly process, in which the few layer graphene is continuously prepared in gas phase by one-step pyrolysis of methane by alternative-current arc plasma under substrate free and atmospheric conditions. The graphene is generated in high purity with the yield of more than 2 g/h. No further operations such as centrifugation, purification, sonication, and drying are needed. The synthesized graphene powder mainly consists of 1-3 layered flakes. The electrochemical performance of the graphene as the cathode conductive filler for LiFePO4 lithium ion batteries is investigated. The most effective electron transporting network in lithium ion batteries is obtained under 2% of graphene, together with 1% of carbon black. Moreover, the addition of graphene increases the specific capacity of the cathode and shows a good rate performance. (C) 2020 The Authors. Published by Elsevier B.V.