Interlayer Conducting Mechanism in α-LiAlO<sub>2</sub> Enables Fast Proton Transport with Low Activation Energy for Solid Oxide Fuel Cells
Yuhao Xiang, Cong Jiang, Dan Zheng, Xiaomi Zhou, Hongdong Cai, Kai Wang, Xia Chen, Xunying Wang, Wenjing Dong, Min Huang, Hao Wang, Baoyuan Wang
Abstract
The α-NaFeO2 structure-type oxides, such as LiNiO2, LiCoO2, and α-LiAlO2, could not only provide channels for Li+ conduction but also conduct protons through intercalation. However, the detailed conduction mechanism of protons in the layer structure oxide needs to be further distinguished. In this work, we prepared layered-oxide α-Li0.88AlO2 and used it as an electrolyte to assemble a solid oxide fuel cell (SOFC), which delivered an output of 1046 mW cm–2 at 550 °C, a decent power output is ascribed to the excellent ion conductivity (0.2 S cm–1) and low activation energy (0.36 eV) of the α-Li0.88AlO2 electrolyte. Moreover, the H/D isotope experiments revealed that the proton dominated the ion conduction of α-Li0.88AlO2. First-principles calculations indicate that the special structure-layered oxides provide channels that allow protons to transfer rapidly with low activation energy. This work indicates the possibility of using layered oxides as proton conductors in a low-temperature SOFC (LT-SOFC) and reveals the proton transport mechanism in oxides, it provides a new approach to exploit novel electrolytes for LT-SOFC.