Microstructure and proton-conducting properties of inorganic nanocomposites

A novel fast proton-conducting silicophosphate-HClO4 (SiP-HClO4) gel and SiP-HClO4-alumina composite were successfully fabricated. The composite sample showed high electrochemical stability, and high thermal stability up to 200degreesC in wet air. The composite showed stable conductivity region at 100degreesC - 120degreesC of gas temperature, indicating a high proton conductivity over 2.6 x 10(-2.)S/CM. The high conductivity of the composite is attributed to the fast proton-conducting property of 3-dimensional SiP-HClO4 gel network in which both the trapped solid acids (HClO4) as a proton source and the strongly hydrogen-bonded hydroxyl groups combined to P-O-Si oxide bonds that work as a proton conduction path are contained.