Understanding Electrochemical Reaction Mechanisms of All-Electrochem-Active Mg 2 Si Electrode in All-Solid-State Batteries

• Published in: Inorganic chemistry 2024-11, Vol.63 (47), p.22542-22548
• Main Authors: Cai, Ziwei, Xu, Zhibin, Zhang, Nan, Peng, Tao, Tan, Yingxiang, Zhong, Hai, Liu, Xingjiang, Mai, Yaohua
• Format: Article
• Language: English
• ISSN: 0020-1669; 1520-510X
• DOI: 10.1021/acs.inorgchem.4c03940

To better understand the electrochemical reaction mechanism of the Mg Si electrode in all-solid-state batteries (ASSBs), a rational all-electrochem-active Mg Si electrode is first designed to minimize the inactive component-related interfacial degradation. This is due to its unique mixed conductivity properties, including a high electronic conductivity of up to 8.9 × 10 S cm and an ionic conductivity of 9.7 × 10 S cm , which allow for fast charges transport. In ASSBs, the Mg Si electrode exhibits a higher initial Coulombic efficiency of 83.5% at 300 mA g compared with the Si electrode (72.3%). X-ray diffraction and X-ray photoelectron spectroscopy results demonstrate that intermediate products (Li Mg Si, Li-Si alloy, and Li-Mg alloy) can form when the Mg Si electrode discharges to 0.01 V, and partial Mg Si still does not react with lithium. This work provides valuable insights into the reaction mechanisms and guides optimization strategies for developing next-generation Si-based ASSBs.