Researchers from the University of Science and Technology of China, led by Professor Zhi-Peng Li, have made significant strides in understanding proton conduction in solid-state oxides, a critical area of study for advancing energy technologies such as fuel cells and electrolyzers. Their work, published in the journal Nature Communications, sheds light on the complex interactions between protons in these materials and offers insights into improving their performance.
Proton-conducting solid oxides are essential components in various energy devices, as they facilitate the efficient transport of protons, which are crucial for electrochemical reactions. However, the precise mechanisms governing proton movement and interaction within these materials have remained elusive. The team of researchers, including Hang Ma, Jiajun Linghu, Nannan Han, Ying Liang, Yiyang Sun, and Tianxing Ma, sought to address this gap by conducting a detailed computational analysis of proton-proton interactions in yttrium-doped barium zirconate (Y-doped BaZrO3).
The study revealed that the interaction between protons in Y-doped BaZrO3 is significantly influenced by lattice distortions. When a proton is positioned at a site where the lattice is bent inward due to the presence of another proton, the interaction between the two protons becomes repulsive, leading to an unstable configuration. Conversely, if a proton is situated at a nearby outward-bending site, it tends to form a stable pair with another proton. This finding highlights the critical role of lattice distortions in mediating proton interactions and stability.
Moreover, the researchers discovered that the site where two protons form the lowest-energy configuration also acts as a trapping site for protons. This trapping effect hinders proton conduction, as it increases the energy barriers that protons must overcome to move through the material. By calculating the diffusion pathways accessible to protons under different local environments, the team found that the energy barriers for two-proton conduction range from 0.24 to 0.45 eV, while those for single-proton conduction range from 0.19 to 0.39 eV. The higher barriers in the two-proton pathways suggest that proton pairing and trapping significantly impede proton movement.
The insights gained from this study provide a theoretical foundation for the experimental design of electrolytes with enhanced proton conductivity. By understanding the factors that influence proton interactions and trapping, researchers can develop strategies to optimize the performance of solid-state oxides in energy devices. This work not only advances our fundamental understanding of proton conduction but also paves the way for the development of more efficient and durable energy technologies.
The research was published in Nature Communications, a prestigious journal known for its high-impact studies in the fields of natural sciences and physical sciences. The findings represent a significant step forward in the quest to improve the efficiency and reliability of energy devices that rely on proton-conducting solid oxides.
This article is based on research available at arXiv.