A fire- safe Li metal battery via smart gas management

• 成果类型: Article
• 署名作者: Guo, Jun-Chen; Chai, Cong-Zheng; Wang, Ya-Hui; Zhao, Yao; Xin, Sen; Zhang, Ying; Guo, Yu-Guo; Bai, Chunli
• 署名单位: Chinese Academy of Sciences; Institute of Chemistry, CAS; Chinese Academy of Sciences; University of Chinese Academy of Sciences, CAS; Chinese Academy of Sciences; Institute of Chemistry, CAS
• 刊物名称: PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA
• ISSN/ISSBN: 0027-14266
• DOI: 10.1073/pnas.2501549122
• 发表日期: 2025-07-22
• 关键词: thermal runaway; lithium; STABILITY; anode

摘要

Lithium (Li) metal batteries offer high energy density but face significant safety challenges due togas evolution under thermal abuse conditions. At the anode, the reduction of organic carbonate-based electrolytes generates flammable gases (e.g., H2, CH4), while the poor thermal stability of the cathode results in the release of O2, CO, and CO2. The accumulation of these gases contributes to mechanical rupture, and their migration further exacerbates thermal runaway. To address these challenges, we propose a smart gas management strategy that constructs continuous flame-retardant interfaces (FRIs) by incorporating flame-retardant polymers (FRPs) into the cathode. Smart gas management is defined as the ability to suppress gas production, alter gas composition to reduce flammability, and mitigate internal pressure buildup, thereby preventing thermal runaway. The FRIs significantly enhance the thermal stability of the cathode by suppressing oxygen release and minimizing electrolyte oxidation caused by active oxygen species. Additionally, the FRP releases flame-retardant radicals that diffuse into the electrolyte, interrupting reactions that generate flammable gases at the anode. This dual-action mechanism reduces gas production and mitigates the risks associated with thermal runaway, forming the foundation of a smart gas management strategy. With this strategy, we demonstrate zero thermal runaway in a 0.58-Ah Li||NCM811 pouch cell with 100% state of charge under thermal abuse conditions. This approach is highly compatible with current manufacturing processes, offering a scalable solution for improving the safety of high-energy-density Li metal batteries. This work provides a promising pathway toward fire-safe Li metal batteries for electric vehicles and other energy storage applications. Significance Flammable gases generated during thermal runaway critically impact the safety of high-energydensity Li metal batteries. Here, we demonstrate that incorporating flame-retardant interfaces (FRIs) into the cathode enables a smart response to thermal abuse, significantly suppressing gas generation and altering gas composition. FRIs reduce oxygen release at the cathode and alter the gas composition at the full-cell level, which helps lower flammability and prevents mechanical rupture. Additionally, the self-heating rate of the improved cells is reduced by 4 orders of magnitude, achieving zero thermal runaway in pouch cells. This smart gas management strategy enhances both thermal safety and electrochemical stability, offering a transformative pathway to fire-safe Li metal batteries for advanced energy storage applications.