Anisotropically layered 2D-3D biocarbon-carbon functionality in sustainable high-performance composite for bipolar plates in fuel cell

Introduction: of novel functional materials to improve the performance of hydrogen-based powertrain component is highly demanding for renewable energy source in the transportation sector. In this research work, novel and highly conductive carbonaceous biomaterials were introduced as an alternative to non-renewable and costprohibitive nanoparticles to improve conductivity along with enhanced flexural strength for fuel cell's bipolar plates. Different physical and chemical changes in molecular and lattice structure during carbonization were analyzed with the help of advanced characterization process. Biocarbons from different renewable sources such as lignin, softwood and hardwood species led to the potential use of waste biomass in high-end functional bipolar plate composite for fuel cell application. A turbostratic-to-graphitic conversion phenomenon including condensed aromatic C--C bond formation, transformation of aliphatic to aromatic components, release of free radicals, occurring lattice imperfections as well as increasing sp2 electron configuration helps to achieve improved composite attributes. This graphitic biocarbon derived polymer composites exceeds the US DOE criteria for hydrogen fuel cell bipolar plates with electrical conductivity of 202 S/cm and flexural strength up to 52 MPa. This pioneering design combined with unique interfacial characteristics of graphitic biocarbon in polymer phase shows a huge potential for fuel cell bipolar plates imparting multifunctional characteristics.