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.