Liu Huaxin, Zhu Fangjun, Zhang Yinghao, Liu Yuming, Zhang Yi, Deng Wentao, Zou Guoqiang, Hou Hongshuai, Ji Xiaobo
State Key Laboratory of Powder Metallurgy, College of Chemistry and Chemical Engineering, Central South University, Changsha, 410083, China.
Angew Chem Int Ed Engl. 2025 Jun 24;64(26):e202505230. doi: 10.1002/anie.202505230. Epub 2025 Apr 26.
Low ionic conductivity, poor mechanical strength, and unstable interface structure are still the main factors hindering the practical application of polymer solid-state lithium metal batteries (SSLMBs). In this work, we have developed a unique composite filler (LLZTOCDs) for solid polymer electrolytes to address these challenges through synergistic regulation of multi-interface chemistry. The LLZTOCDs is prepared via thermal treatment of N,S,F-codoped carbon dots (NSFCDs) and LiLaZrTaO (LLZTO) inorganic electrolyte. Here, the detrimental LiCO on the LLZTO surface is converted into a fast ion-conducting and an electron-insulating interlayer of LiF and LiN, and the carbon dots self-assemble into a functional organophilic coating on the outermost layer, which acts as a bridge between the LLZTO and the polymer. This unique structure enhances the compatibility and ion-exchange kinetics between the LLZTOCDs and the polymer, significantly improving the mechanical strength and Li transport. Additionally, the oxygen vacancies formed in situ at the LLZTOCDs interface provide an anion confinement effect, increasing lithium salt dissociation, and enhancing the Li transference number to 0.85. Therefore, the solid battery constructed with LLZTOCDs exhibits excellent electrochemical stability, long-cycle life, and high ionic conductivity (1.96 × 10 S cm at 25 °C), providing a feasible strategy for practical applications.
低离子电导率、较差的机械强度和不稳定的界面结构仍然是阻碍聚合物固态锂金属电池（SSLMBs）实际应用的主要因素。在这项工作中，我们开发了一种用于固体聚合物电解质的独特复合填料（LLZTOCDs），通过多界面化学的协同调控来应对这些挑战。LLZTOCDs是通过对N、S、F共掺杂碳点（NSFCDs）和LiLaZrTaO（LLZTO）无机电解质进行热处理制备而成。在此过程中，LLZTO表面有害的LiCO转化为LiF和LiN的快速离子传导且电子绝缘的中间层，而碳点在最外层自组装形成功能性亲有机涂层，该涂层充当LLZTO与聚合物之间的桥梁。这种独特结构增强了LLZTOCDs与聚合物之间的相容性和离子交换动力学，显著提高了机械强度和Li传输性能。此外，在LLZTOCDs界面原位形成的氧空位提供了阴离子限制效应，增加了锂盐解离，并将Li迁移数提高到0.85。因此，采用LLZTOCDs构建的固态电池表现出优异的电化学稳定性、长循环寿命和高离子电导率（25℃时为1.96×10 S cm），为实际应用提供了一种可行的策略。
