Highly-conductive composite bipolar plate based on ternary carbon materials and its performance in redox flow batteries

Redox flow battery has become one of the most promising technologies for large-scale energy storage. However, as a key component, bipolar plate is still under development to achieve high electrical conductivity and sufficient flexural strength simultaneously. With this purpose, an innovative low-carbon-content bipolar plate with hybrid conductive materials of graphene, carbon fibers and graphite powders are prepared. Morphology, flexural strength, electrical conductivity, corrosion resistance, vanadium permeability and single cell performance are studied and discussed. Extremely low area specific resistance (5.0 mΩ cm2) and high in-plane electrical conductivity (420.6 S cm−1) are achieved at an ultra-low carbon content of 25 wt%. The voltage efficiency and energy efficiency of the vanadium redox flow battery unit cell reach as high as 88.0% and 85.9%, respectively, at 100 mA cm−2. The low-carbon-content bipolar plate turns to be promising for the massive application in redox flow batteries.