High-Performance NiCu Graphite-Felt Anode Based on in Situ Exfoliating Graphene for Direct Ammonia Fuel Cells

Abstract

Abstract Direct ammonia fuel cell (DAFC) has broad prospects in the field of sustainable energy due to their advantages, including high energy density and zero carbon emissions. However, the slow kinetics of ammonia oxidation reaction (AOR) in low-cost non-noble metal anode, along with insufficient conductivity and stability, restricts the practical application of DAFCs. Herein, a novel NiCu/exfoliated-graphite-felt (EGF) composite electrode is successfully fabricated via a synergistic strategy integrating electrochemical in situ exfoliating graphene and NiCu alloy electrodeposition. Due to the in situ growth of graphene nanosheets on the GF surfaces, the conductivity and microstructure of the graphite felt (GF) substrate are significantly improved. NiCu alloy nanospheres are uniformly and porously distributed on the EGF by stepwise electrodeposition method to make full use of the synergistic catalytic effect of alloy and expose abundant active sites, further acquiring catalytic performance of AOR. The composite electrode achieves a maximum current density of 482 mA cm–2, 2.28 times that of the NiCu/original-GF electrode, and maintains 18 h at above 237 mA cm–2. In a DAFC with NiCu/EGF anode, the maximum power density reaches 21.53 mW cm–2. Results reveal that a new approach to obtain excellent catalytic performance and long-term stability is provided for DAFCs.