Synthesis of phosphonated graphene oxide by electrochemical exfoliation to enhance the performance and durability of high-temperature proton exchange membrane fuel cells

The doping of functionalized graphene oxide (GO) in the membranes becomes a promising method for improving the performance of high-temperature proton exchange membrane fuel cells (HT-PEMFC). Phosphonated graphene oxide (PGO) with a P/O ratio of 8.5% was quickly synthesised by one-step electrochemical exfoliation based on a three-dimensiaonal (3D) printed reactor and natural graphite flakes. Compared with the GO prepared by the two-step electrochemical exfoliation method, the PGO synthesized by the one-step electrochemical exfoliation can better improve the performance of the membrane-electrode-assembly (MEA) based on the polybenzimidazole (PBI) membrane in the HT-PEMFC. The doping of 1.5 wt% GO synthesised by electrochemical exfoliation with the 2-step method or reactor method in PBI increased the peak power density by 17.4% or 35.4% compared to MEA based on pure PBI membrane at 150 °C, respectively. In addition, the doping of PGO in PBI improves its durability under accelerated stress test (AST).