Liu Yuncong, Jin Zhekai, Liu Zeyu, Xu Hao, Sun Furong, Zhang Xue-Qiang, Chen Tao, Wang Chao
Key Lab of Organic Optoelectronics & Molecular Engineering, Department of Chemistry, Tsinghua University, Beijing, 100084, P. R. China.
Beijing Key Laboratory of Green Chemical, Reaction Engineering and Technology, Department of Chemical Engineering, Tsinghua University, Beijing, 100084, P. R. China.
Angew Chem Int Ed Engl. 2024 Aug 19;63(34):e202405802. doi: 10.1002/anie.202405802. Epub 2024 Jul 19.
Solid polymer electrolytes are promising electrolytes for safe and high-energy-density lithium metal batteries. However, traditional ether-based polymer electrolytes are limited by their low lithium-ion conductivity and narrow electrochemical window because of the well-defined and intimated Li-oxygen binding topologies in the solvation structure. Herein, we proposed a new strategy to reduce the Li-polymer interaction and strengthen the anion-polymer interaction by combining strong Li-O (ether) interactions, weak Li-O (ester) interactions with steric hindrance in polymer electrolytes. In this way, a polymer electrolyte with a high lithium ion transference number (0.80) and anion-rich solvation structure is obtained. This polymer electrolyte possesses a wide electrochemical window (5.5 V versus Li/Li) and compatibility with both Li metal anode and high-voltage NCM cathode. Li||LiNiCoMnO full cells with middle-high active material areal loading (~7.5 mg cm) can stably cycle at 4.5 V. This work provides new insight into the design of polymer electrolytes for high-energy-density lithium metal batteries through the regulation of ion-dipole interactions.
固态聚合物电解质是用于安全且高能量密度锂金属电池的有前景的电解质。然而，传统的基于醚的聚合物电解质由于溶剂化结构中明确且紧密的锂-氧结合拓扑结构，其锂离子电导率低且电化学窗口窄，受到限制。在此，我们提出了一种新策略，通过在聚合物电解质中结合强的锂-氧（醚）相互作用、弱的锂-氧（酯）相互作用和空间位阻，来减少锂-聚合物相互作用并增强阴离子-聚合物相互作用。通过这种方式，获得了一种具有高锂离子迁移数（0.80）和富阴离子溶剂化结构的聚合物电解质。这种聚合物电解质具有宽的电化学窗口（相对于Li/Li为5.5 V）以及与锂金属负极和高压NCM正极的兼容性。具有中高活性材料面负载（~7.5 mg cm）的Li||LiNiCoMnO全电池能够在4.5 V下稳定循环。这项工作通过调控离子-偶极相互作用，为高能量密度锂金属电池的聚合物电解质设计提供了新的见解。
