Commercial preparation of hybrid carbon filler/HDPE composite electrodes for lead methanesulfonate flow batteries

ABSTRACT High-density polyethylene (HDPE) conductive polymer composites are prepared using carbon fillers, such as natural flake graphite (FG), carbon black (CB), and carbon fibre (CF). Here, micro-sized FG as the main conductive filler, nano-sized CB as assistant conductive filler, and short CF as flexibility-enhanced materials are internally mixed with HDPE in a certain weight ratio. Commercial conductive polymer composite is prepared by hot pressing technology. Two kinds of conductive composites are selected by optimising the ratio of carbon fillers and HDPE. CF4%(CB + FG)1:5HDPE27% composite has the higher volume conductivity of 20.76 S cm−1 with a bending strength of 39.5 MPa. CF4%(CB + FG)1:4HDPE30% composite has the larger bending strength of 53.6 MPa with a volume conductivity of 18.82 S cm−1. The electrochemical corrosion resistances of those two composite electrodes are investigated over 900 charging/discharging cycles in the lead methanesulfonate flow cell. CF4%(CB + FG)1:4HDPE30% composite exhibits better durability than CF4%(CB + FG)1:5HDPE27% composite.