Abstract
AbstractLow temperature ionic conducting materials such as OH− and H+ ionic conductors are important electrolytes for electrochemical devices. Here we show the discovery of mixed OH−/H+ conduction in ceramic materials. SrZr0.8Y0.2O3-δ exhibits a high ionic conductivity of approximately 0.01 S cm−1 at 90 °C in both water and wet air, which has been demonstrated by direct ammonia fuel cells. Neutron diffraction confirms the presence of OD bonds in the lattice of deuterated SrZr0.8Y0.2O3-δ. The OH− ionic conduction of CaZr0.8Y0.2O3-δ in water was demonstrated by electrolysis of both H218O and D2O. The ionic conductivity of CaZr0.8Y0.2O3-δ in 6 M KOH solution is around 0.1 S cm−1 at 90 °C, 100 times higher than that in pure water, indicating increased OH− ionic conductivity with a higher concentration of feed OH− ions. Density functional theory calculations suggest the diffusion of OH− ions relies on oxygen vacancies and temporarily formed hydrogen bonds. This opens a window to discovering new ceramic ionic conducting materials for near ambient temperature fuel cells, electrolysers and other electrochemical devices.
Funder
RCUK | Engineering and Physical Sciences Research Council
Innovate UK
Publisher
Springer Science and Business Media LLC
Subject
General Physics and Astronomy,General Biochemistry, Genetics and Molecular Biology,General Chemistry,Multidisciplinary
Reference88 articles.
1. Steele, B. C. H. & Heinzel, A. Materials for fuel-cell technologies. Nature 414, 345–352 (2001).
2. Tao, S. & Irvine, J. T. S. A redox-stable efficient anode for solid-oxide fuel cells. Nat. Mater. 2, 320–323 (2003).
3. Zhang, L. et al. A review of the chemical compatibility between oxide electrodes and electrolytes in solid oxide fuel cells. J. Power Sources 492, 229630 (2021).
4. Takahashi, T. & Iwahara, H. Solid-state ionics - protonic conduction in perovskite type oxide solid-solutions. Rev. De. Chim. Miner. 17, 243–253 (1980).
5. Ishihara, T., Matsuda, H. & Takita, Y. Doped LaGaO3 perovskite-type oxide as a new oxide ionic conductor. J. Am. Chem. Soc. 116, 3801–3803 (1994).