Nickel 3D Structures Enhanced by Electrodeposition of Nickel Nanoparticles as High Performance Anodes for Direct Borohydride Fuel Cells

International audience; Direct borohydride fuel cell (DBFC) is a promising technology to power portable and mobile devices thanks to their high theoretical voltage and good energy density. Carbon‐supported electrodeposited nickel‐metal catalysts (NiED/C) exhibit fast kinetics for the borohydride oxidation reaction (BOR). One key is to deposit nickel‐metal on sufficiently open structures to make electrodes compatible with fast mass‐transfer, so as to further optimize the fuel cell performance. To that goal, Ni foams (NFM) or felts (NFT) can be used. Being inherently surface‐oxidized (passivated) and of too low developed area, these supports were enhanced by both oxides removal/depassivation (using electro‐assisted (or not) acid etching) and nickel electrodeposition, in order to exhibit the combined properties of fast diffusion medium and high‐surface area resulting in the highly‐active catalysts. After such enhancement, NiED/NFT shows superior performance in the BOR compared to carbon‐supported Ni catalysts. To make a fair comparison with PGM, Pt catalysts supported on open carbon structures were also studied and presented slightly smaller performance than the NiED/NFT electrodes, in particular in terms of open‐circuit potential and current density at high cell voltage.