Solid-state lithium metal batteries (SSLMBs) with polymer electrolytes are promising due to enhanced safety and high energy density, but the low ionic conductivity of polymer electrolytes and the unstable interface of lithium metal anode hinder the development of SSLMBs. Herein, we propose a unique strategy to address these challenges by coupling ultrathin high-dielectricity CaNbO (CNO) nanosheets with PEO-based electrolyte. The interfacial polarization originating from the distortion of NbO octahedra along the vertical direction of CNO nanosheets is maximized and so the interaction between CNO and LiTFSI, which greatly supports the dissociation of LiTFSI and improves the ionic conductivity (2.0 × 10 S cm) of the composite polymer electrolyte, compared to that without CNO. The optimized interfacial polarization effect is thoroughly demonstrated by theoretical calculation and experimental results. Moreover, due to a homogeneous, robust and LiF-rich solid electrolyte interphase film with promoted Li ion transport being formed at the lithium metal interface, the superior cycling stability (90 % capacity retention after 440 cycles at 0.5 C) and rate capability for LFP||Li full batteries are achieved. This design of composite polymer electrolyte with ultrathin dielectric nanosheet fillers demonstrates a new approach to the development of high-performance polymer electrolytes for SSLMBs.

中文翻译：

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识别高性能固态锂金属电池的超薄介电纳米片引起的界面极化


采用聚合物电解质的固态锂金属电池（SSLMB）由于增强的安全性和高能量密度而具有广阔的前景，但聚合物电解质的低离子电导率和锂金属负极的不稳定界面阻碍了SSLMB的发展。在此，我们提出了一种独特的策略，通过将超薄高介电 CaNbO (CNO) 纳米片与 PEO 基电解质耦合来应对这些挑战。由于 NbO 八面体沿 CNO 纳米片垂直方向的扭曲而产生的界面极化最大化，因此 CNO 和 LiTFSI 之间的相互作用，极大地支持了 LiTFSI 的解离并提高了复合材料的离子电导率（2.0 × 10 S cm）聚合物电解质，与不含CNO的电解质相比。理论计算和实验结果充分证明了优化后的界面极化效果。此外，由于在锂金属界面形成均匀、坚固且富含 LiF 的固体电解质中间膜，并促进锂离子传输，LFP 具有优异的循环稳定性（0.5 C 下 440 次循环后容量保持率为 90%）和倍率能力||实现锂全电池。这种具有超薄介电纳米片填料的复合聚合物电解质的设计展示了开发用于 SSLMB 的高性能聚合物电解质的新方法。