The development of solid-state proton conductors with high proton conductivity at low temperatures is crucial for the implementation of hydrogen-based technologies for portable and automotive applications. Here, we report on the discovery of a new crystalline metal acid triphosphate, ZrH5(PO4)3 (ZP3), which exhibits record-high proton conductivity of 0.5–3.1×10−2 S cm−1 in the range 25–110 °C in anhydrous conditions. This is the highest anhydrous proton conductivity ever reported in a crystalline solid proton conductor in the range 25–110 °C. Superprotonic conductivity in ZP3 is enabled by extended defective frustrated hydrogen bond chains, where the protons are dynamically disordered over two oxygen centers. The high proton conductivity and stability in anhydrous conditions make ZP3 an excellent candidate for innovative applications in fuel cells without the need for complex water management systems, and in other energy technologies requiring fast proton transfer.
Bibliographical noteFunding Information:
S.F. gratefully acknowledges the Ramsay Memorial Trust and the University of Aberdeen's School of Natural and Computing Sciences for the provision of a Ramsay Memorial Fellowship. This paper benefited from the insights of Professor Giulio Alberti who was a pioneer and one of the most authoritative scientists of the chemistry of M phosphates and phosphonates. IV
A previous version of this manuscript has been deposited on a preprint server (https://doi.org/10.26434/chemrxiv-2022-2h4g1).
- Conducting Materials
- Fuel Cells
- Proton Conductivity
- Solid Acids
- Zirconium Phosphates