Solid‐state Li batteries using Na⁺ superionic conductor type solid electrolyte attracts wide interest because of its safety and high theoretical energy density. The NASCION type solid electrolyte LAGP (Li_1.5Al_0.5Ge_0.5P₃O₁₂) shows favorable conductivity as well as good mechanical strength to prevent Li dendrite penetration. However, the instability of LAGP with Li metal remains a great challenge. In this work, an amorphous Ge thin film is sputtered on an LAGP surface, which can not only suppress the reduction reaction of Ge⁴⁺ and Li, but also produces intimate contact between the Li metal and the LAGP solid electrolyte. The symmetric cell with the Ge‐coated LAGP solid electrolyte shows superior stability and cycle performance for 100 cycles at 0.1 mA cm⁻². A quasi‐solid‐state Li–air battery has also been assembled to further demonstrate this advantage. A stable cycling performance of 30 cycles in ambient air can be obtained. This work helps to achieve a stable and ionic conducting interface in solid‐state Li batteries.

中文翻译：

---

固态锂电池用锗薄膜保护的磷酸锂铝锗

使用Na ⁺超离子导体型固体电解质的固态锂电池由于其安全性和较高的理论能量密度而引起了广泛的关注。NASCION型固体电解质LAGP（Li _{1. 5} Al _0.5 Ge _0.5 P ₃ O ₁₂）显示出良好的导电性以及良好的机械强度以防止Li树枝状晶体渗透。但是，LAGP与锂金属的不稳定性仍然是一个巨大的挑战。在这项工作中，在LAGP表面上溅射了非晶态的Ge薄膜，这不仅可以抑制Ge ⁴⁺的还原反应和锂，但也会在锂金属和LAGP固体电解质之间产生紧密接触。带有Ge涂层的LAGP固体电解质的对称电池在0.1 mA cm ^-2的100个循环中显示出卓越的稳定性和循环性能。还组装了准固态锂空气电池，以进一步证明这一优势。在环境空气中可获得30个循环的稳定循环性能。这项工作有助于在固态锂电池中实现稳定的离子导电界面。