Relationship between electrical conductivities and structure of hybrid materials derived from mixtures of zinc phosphate glasses with different phosphate-chain lengths and benzimidazole

Abstract

Here, we report unique anhydrous proton-conducting hybrid materials derived from mixtures of benzimidazole and zinc metaphosphate glass. Benzimidazole, which melts at 170 °C, caused breaking of the phosphate chains in the glasses, resulting in the formation of hybrid materials. In the present work, various hybrid materials were prepared to clarify the effects of parent glass composition on their electrical conductivities. In the case of 53P2O5 · 47ZnO glass, which contains Qp1 and Qp2 and Qp3 groups, the phosphate chains were broken easily to form benzimidazole and Qp0 groups. Qpn, where n is the number of bridging oxygens to neighboring tetrahedral, describes the bonding of PO4 tetrahedron. Hybrids prepared using benzimidazole and 42P2O5 · 58ZnO glass (which contains many Qp1 groups) formed the smallest amounts of the Qp0 group-containing products. The hybrid material prepared with 53P2O5 · 47ZnO glass showed the highest conductivity (e.g., ∼1 mS/cm at 190 °C). The electrical conductivities of the hybrid materials may be related to the amounts of Qp0 group-containing products and benzimidazole.