Composite protonic electrolytes in the system (NH4)3H(SO4)2–SiO2
Abstract Transport, thermal and structural properties of (1− x )(NH 4 ) 3 H(SO 4 ) 2 – x SiO 2 composite solid electrolytes ( x =0–0.8) were investigated, and an increase in (NH 4 ) 3 H(SO 4 ) 2 (II) low temperature phase conductivity was shown. The dependence of the low temperature conductivity on x has a smooth maximum with values five to six times higher than that of the pure polycrystalline salt and two orders of magnitude higher than that of single crystals. The (NH 4 ) 3 H(SO 4 ) 2 phase transition temperature in the composites decreases by 20 K with an increase of SiO 2 content from 0 to 0.7. The observed jump in conductivity that coincides with the phase transition becomes more diffuse and disappears at x =0.8. The thermal stability of (NH 4 ) 3 H(SO 4 ) 2 in such composites increases markedly as compared with the pure salt.