Strategically Improving Electrical Conductivity of Reduced Graphene Oxide Through a Series of Reduction Processes

•Graphene oxide electrochemically exfoliated from graphite rod of used batteries.•Three best methods are identified to produce reduced graphene oxide (rGO).•These methods are used in series to produce rGO with best bulk conductivity.•Water based, hydrothermal and microwave reduction sequence produces the best rGO.•The rGO characterized by FTIR, Raman, XRD, etc. to explain its conductivity.