Maity Ayan, Svirinovsky-Arbeli Asya, Buganim Yehuda, Oppenheim Chen, Leskes Michal
Department of Molecular Chemistry and Materials Science, Weizmann Institute of Science, Rehovot, Israel.
Nat Commun. 2024 Nov 17;15(1):9956. doi: 10.1038/s41467-024-54315-w.
Polymer-ceramic composite electrolytes enable safe implementation of Li metal batteries with potentially transformative energy density. Nevertheless, the formation of Li-dendrites and its complex interplay with the Li-metal solid electrolyte interphase (SEI) remain a substantial obstacle which is poorly understood. Here we tackle this issue by a combination of solid-state NMR spectroscopy and Overhauser dynamic nuclear polarization (DNP) which boosts NMR interfacial sensitivity through polarization transfer from the metal conduction electrons. We achieve detailed molecular-level insight into dendrites formation and propagation within the composites and determine the composition and properties of their SEI. We find that the dendrite's quantity and growth path depend on the ceramic content and correlated with battery's lifetime. We show that the enhancement of Li resonances in the SEI occurs through Li/Li charge transfer in Overhauser DNP, allowing us to correlate DNP enhancements and Li transport and directly determine the SEI lithium permeability. These findings have promising implications for SEI design and dendrites management which are essential for the realization of Li metal batteries.
聚合物-陶瓷复合电解质能够安全实现具有潜在变革性能量密度的锂金属电池。然而，锂枝晶的形成及其与锂金属固体电解质界面（SEI）的复杂相互作用仍然是一个重大障碍，目前人们对此了解甚少。在这里，我们通过固态核磁共振光谱和奥弗豪泽动态核极化（DNP）相结合的方法来解决这个问题，DNP通过从金属传导电子的极化转移提高了核磁共振界面灵敏度。我们对枝晶在复合材料中的形成和生长有了详细的分子水平洞察，并确定了其SEI的组成和性质。我们发现枝晶的数量和生长路径取决于陶瓷含量，并与电池寿命相关。我们表明，在奥弗豪泽DNP中，SEI中锂共振的增强是通过Li/Li电荷转移实现的，这使我们能够将DNP增强与锂传输相关联，并直接确定SEI锂渗透率。这些发现对SEI设计和枝晶管理具有有前景的意义，而这对于锂金属电池的实现至关重要。
