Characterization of ceramic materials for electrochemical hydrogen sensors

Accurate and reliable tritium management is of basic importance for the correct operation conditions of the blanket tritium cycle. The Electrochemical Methods Lab at Institut Quimic de Sarria (IQS) is working in the design and development of tritium sensors, based on proton solid state electrolytes to be used in molten lithium-lead eutectic. Different solid electrolyte proton conductors have been synthesized (Sr₃CaZr_0.9Ta _1.1O_8.55, SrCe_0.95Yb_0.05O _3-α, CaZr_0.9In_0.1O_3-α, Ba₃(Ca_1.18Nb_1.82)O_9-α) in order to be evaluated in a testing apparatus for hydrogen gas. Potentiometric measurements of the synthesized ceramic elements have been performed. In all experiments the working temperature was 500 °C. The sensors constructed using the proton conductor element Sr₃CaZr_0.9Ta _1.1O_8.55 exhibited stable output potential and its value was close to the theoretical value calculated with the Nernst equation. When the proton conductor elements SrCe_0.95Yb_0.05O _3-α and CaZr_0.9In_0.1O_3-α and Ba₃(Ca_1.18Nb_1.82)O_9-α were used a deviation higher than 100 mV between theoretical and experimental data was obtained.