化学镀制备高温质子导体镍电极及其电化学性能

采用化学镀在高温质子导体CaZr_0.9In_0.1O_3-δ (CZI)的电解质陶瓷表面沉积金属镍电极, 通过SEM显微结构分析比较了酸刻蚀和还原工艺对电极形貌以及电极-电解质界面的影响。结果表明, 使用HNO₃-HCl混合刻蚀液, 并以水合肼为还原剂的二次化学镀可获得颗粒均匀细小且界面结合良好的镍电极。通过电化学阻抗谱并结合浓差电池等方法研究比较了以化学镀镍电极和涂覆焙烧铂电极为电极, CZI为电解质的对称电池的电导率和质子迁移率。工作温度为800℃时, 镍电极高温质子导体的总电导率为4.131×10^-4 S/cm, 并且工作温度在400℃以上时, 镍电极对称电池的质子迁移率均接近100%。这些结果表明, 二次化学镀制备的镍电极具有与铂电极相近的电化学性能, 而成本则更低, 可以取代Pt电极用于高温质子导体的电化学器件中。

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 CaZr_0.9In_0.1O_3-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 athe noble platinum catalyst electrode.