A synergistic approach to achieving high conduction and stability of CsH2PO4/NaH2PO4/ZrO2 composites for fuel cells

Abstract

Solid acid composites of CsH₂PO₄/NaH₂PO₄/ZrO₂ with different weight ratios of CsH₂PO₄ (CDP), NaH₂PO₄ (SDP), and ZrO₂ were synthesized and characterized. The structure and morphology of the composites were investigated by XRD, FESEM, EDX, and FTIR techniques. The thermal stability and conduction were described for the solid acid composites using TGA, DTA, and conductivity measurements. NaH₂PO₄ increased the low-temperature conductivity of CDP by up to 1.5 orders of magnitude and ZrO₂ enhanced the conductivity above the transition temperatures. Additionally, the composites showed excellent stability. The superprotonic transition behavior was identified at temperatures from 220 to 270 °C. The conductivity of the composites was examined in air and under confined conditions and also their decomposition was investigated. Our findings suggest that NaH₂PO₄/ZrO₂ is an appropriate composite for achieving the high conductivity and stability of CDP.