A parametric study of crystal structure, phase stability, and conductivity of the novel phosphate-based composite electrolyte

This novel research focused on synthesizing a series of new proton conductive electrolytes of CsH₂PO₄ and CeP₂O₇ by chemical reaction method, in which phase purity, functional groups, thermal stability, and ionic conductivity were investigated. The composite electrolyte showed improvement in conductivity by about 4 orders of magnitude with oxide ion conduction observed with a value of 4.16 × 10^–2 S cm^–1. This work provides a comprehensive view of the underlying oxide ion migration mechanism for CsH₂PO₄ with tetravalent pyrophosphate-based composites. CsH₂PO₄ and pyrophosphate have gained significant interest as proton conductors for electrolyte application. The crystal growth approach developed here will prove useful for obtaining compounds that are thermodynamically favorable at temperatures close to ambient and the composite electrolytes confirm the practical suitability of the presented material to be used for intermediate-temperature fuel cells.