Changes: Optimizing morphology and chemistry of nickel surfaces by a scalable plasma process for hydrogen electrolyzers

Surface pre-treatment is an important step in many manufacturing processes. This includes chemical or morphological modification of the surface, to specifically tailor certain characteristics for later manufacturing steps. Increasing the surface roughness is one form of pre-treatment used for example in electrode manufacturing for electrolyzers, or for soldering pads in power electronics. The process presented in this study applies a nitrogen plasma to nickel surfaces and modifies these to a porous network of nickel nitride with a wide range of pore sizes, ranging from few nanometers in diameter to around 800 μ m . This provides significantly increased specific surface area. This plasma process avoids less desirable factors of traditionally used methods to increase surface roughness. The effect observed is investigated, key driving factors are identified and a model for the structure formation is proposed. • Nitrogen plasma creates multiscalar porous nickel nitride with nm to µm pores • Diffusion along crystal defects drives structure formation in nickel substrates • Optimal OES fingerprinting enables process transfer between different reactor types • Scalable, eco-friendly alternative for increasing nickel surface area and nitriding • Optimizing electrode performance and stability in hydrogen electrolyzers