Solid-state electrolyte for solid-state batteries is one of the current hotspots in the research field of high-safety and high energy density lithium metal batteries. This work reports a polymer-in-ceramic and ceramic-in-polymer bilayer ultrathin (∼11 μm) composite solid electrolyte (CSE) membrane by exploiting a spontaneous precipitation of Li₇La₃Zr₂O₁₂ in a polymer-lithium salt matrix. The polymer-in-ceramic layer is toward a high-voltage cathode, which can effectively inhibit oxidative decomposition of electrolytes. The ceramic-in-polymer layer toward the anode can provide good flexibility. Experimental results show that the CSE bilayer membrane has not only high ionic conductivity but also satisfactory Li⁺ transference number. It also exhibits excellent thermal and mechanical properties. High-voltage Li||LiCoO₂ (4.5 V) cell employing this CSE membrane exhibits excellent cycling stability (151.18 mAh g⁻¹ at 1 C after 100 cycles), and superior rate performance (124.31 mAh g⁻¹ 10 C). This work guides the improvement of both solid state electrolyte membrane and high-voltage solid-state lithium metal batteries.

用于固态电池的固态电解质是当前高安全性和高能量密度锂金属电池研究领域的热点之一。这项工作报告了通过利用 Li ₇ La ₃ Zr ₂ O ₁₂在聚合物-锂盐基质中的自发沉淀，制备了陶瓷聚合物和陶瓷聚合物双层超薄（~11 μm）复合固体电解质（CSE）膜. 陶瓷中聚合物层朝向高压阴极，可有效抑制电解质的氧化分解。朝向阳极的陶瓷聚合物层可以提供良好的柔韧性。实验结果表明，CSE双层膜不仅具有高离子电导率，而且还具有令人满意的Li ⁺转让号码。它还表现出优异的热性能和机械性能。高电压锂||的LiCoO ₂采用该CSE膜表现出优异的循环稳定性（4.5V）电池（151.18毫安克^-1，在100次循环后1个C），以及优异的倍率性能（124.31毫安克^-1 10 C）。这项工作指导了固态电解质膜和高压固态锂金属电池的改进。