The performance of the sodium silicate/graphite composite bipolar plate

Sodium silicate/graphite hydrophilic conductive composite materials were prepared by mould pressing method at room temperature.The effects of graphite content,graphite particle size,the pressure and time of mould pressing on the conductivity of composite materials were discussed.The water content of composite materials with different graphite contents was investigated.The results showed that the conductivity of sodium silicate/graphite conductive composite material could meet the requirement of bipolar plate in PEMFC when the graphite content was 40%.The conductivity of the composite material could be improved by optimizing the mould pressing conditions.The composite material contained gel capillary pores and the water content was about 9%,which would be benefit to humidify proton exchange membrane while the PEMFC operated.