3D graphene-Ni foam heterostructures for highly-efficient and durable bipolar plates in a polymer electrolyte membrane fuel cell

Abstract

​Improving the lifetime of polymer electrolyte membrane fuel cells (PEMFCs) is critical for realizing their implementation as a highly-efficient energy conversion system. However, the chemical instability of metal bipolar plates in the destructive operating environment inside PEMFCs leads to decreased performance and durability. Therefore, rational interface passivation techniques are critical for further boosting the development of PEMFCs. In this work, we report a novel method for coating highly-crystalline multilayer graphene (Gr) as a superficial protective film (thickness of ~10 nm) onto 6 x 6 cm2 Ni foam within short duration (t ≤5 min) via the facile and rapid radiative heating of poly(methyl methacrylate) as a solid-state C source. The resulting 3D Gr-coated Ni foam is demonstrated to act as a bipolar plate with long-term operating stability. Electrochemical analysis revealed that the 3D Gr-coated Ni foam outperforms bare Ni foam and amorphous-C-coated Ni foam by providing a two-order-of-magnitude lower corrosion rate in the operational environment for a PEMFC. After stability tests in aggressive environments, the 3D Gr-coated Ni foam retained its outstanding ICR of 9.3 mΩ∙cm2 at 10.1 kgf∙cm-2. A H2/air PEMFC fabricated using the Gr-coated Ni foam as bipolar plates showed a substantially enhanced maximum power density of ~967 mW∙cm-2. Our facile coating approach can pave the way to further enhance energy conversion systems through interface engineering.