Nickle Electrodes for High-temperature Proton-conducting Electrolytes: Preparation by Electroless Plating and Electrochemical Performance

Nickel layers were deposited on the surface of high-temperature proton-conducting Ca Zr0.9 In0.1 O3–δ（CZI） electrolytes by an electroless plating technique. Effects of acid etching and reduction processes on electrode surface morphology and electrolyte adherence to electrodes were investigated by SEM observation. The results showed that the electrodes prepared by a two-step electroless plating process in HNO3-HCl etching solution with hydrazine reducing agent were uniform and well connected to the electrolyte surface. Conductivity and proton transport rate between Ni-CZI symmetric cell and Pt-CZI symmetric cell were compared by electrochemical impedance spectroscopy and concentration cell test. The total conductivity of the Ni-CZI symmetric cell was 4.131×10–4 S/cm at 800℃, and the proton transport rates of the Ni-CZI symmetric cell were all almost 100% at the operating temperature higher than 400℃. The nickel electrode prepared by two-step electroless plating was achievable at low cost and had a comparable catalytic performance to that of platinum electrode, indicating it a promising candidate to replace the noble platinum catalyst electrode.