Electrochemical property of proton-conductive manganese dioxide for sensoring hydrogen gas concentration

A high-purity, ramsdellite-crystal type manganese dioxide (Koyanaka et al., 2005 [1]; Iikubo et al., 2010 [2]) was used for an electrolyte in a hydrogen gas sensor (Ueda et al., 2011 [3]). In this report, the electrochemical properties of the hydrogen gas sensor using electrolytes made of different crystal types of manganese dioxides, such as the ramsdellite-crystal type, a β-crystal type, and a λ-crystal type were examined. The high-purity, ramsdellite-crystal type manganese dioxide showed the conductivity from 7.1 × 10− 5 S/cm (80 °C) to 1.7 × 10− 4 S/cm (25 °C) under 85% relative humidity condition. This conductivity was probably based on the proton conduction on the MnO2 particles.