A solid polymer electrolyte is expected to be useful for safe and high energy density lithium-metal batteries owing to its good flexibility and high degree of safety. The development of a polyethylene oxide (PEO) based solid electrolyte is still restrained by low ionic conductivity and unsatisfactory mechanical strength. Since MnO₂ could combine with PEO chains and Li ions could undergo long-range migration on MnO₂ nanosheets, MnO₂ nanoflakes are chosen as fillers to improve the electrochemical and mechanical properties of a solid polymer electrolyte. A PEO/MnO₂ composite solid polymer electrolyte (CSPE) displays a higher lithium ion transference number (0.378), higher ionic conductivity (1.5 times higher at 60 °C) and better tensile strength (2.3 times) than a PEO solid electrolyte. Density functional theory calculations reflect the fact that the binding energy between the PEO/Li complex and MnO₂ is small and there is easy desorption of Li from PEO and migration on MnO₂ nanosheets, indicating enhanced lithium ion transport in the electrolyte system. A solid-state lithium metal battery using a PEO/MnO₂ CSPE delivers higher capacity (143.5 mA h g⁻¹ after 300 cycles) than an electrolyte without fillers (61.2 mA h g⁻¹ after 90 cycles). Soft-package lithium metal batteries with an MnO₂ CSPE reveal high safety after cutting, nail and bending tests.

中文翻译：

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包含MnO ₂纳米片的复合固体聚合物电解质，具有增强的机械性能和电化学稳定性，适用于锂金属电池†

固体聚合物电解质由于其良好的柔韧性和高度的安全性，有望用于安全和高能量密度的锂金属电池。低离子电导率和令人满意的机械强度仍然限制了基于聚环氧乙烷（PEO）的固体电解质的发展。由于MnO ₂可以与PEO链结合并且Li离子可以在MnO ₂纳米片上进行长距离迁移，因此选择MnO ₂纳米薄片作为填料可以改善固体聚合物电解质的电化学和机械性能。PEO / MnO ₂与PEO固体电解质相比，复合固体聚合物电解质（CSPE）具有更高的锂离子转移数（0.378），更高的离子电导率（在60°C时是1.5倍）和更好的拉伸强度（2.3倍）。密度泛函理论计算反映了这样一个事实，即PEO / Li络合物与MnO ₂之间的结合能很小，并且Li很容易从PEO上解吸，并易于在MnO ₂纳米片上迁移，这表明电解质系统中锂离子的传输增强。与没有填料的电解质（61.2 mA hg ^-1）相比，使用PEO / MnO ₂ CSPE的固态锂金属电池可提供更高的容量（300次循环后为143.5 mA hg ^-1）90个周期后）。带有MnO ₂ CSPE的软包装锂金属电池在切割，打钉和弯曲测试后显示出很高的安全性。