Uniform lithium (Li) deposition in all-solid-state Li metal batteries is greatly influenced by the anode/electrolyte interface. Herein, a Mg-modified interface was constructed via the simple in-situ electrochemical reduction of Mg²⁺ from Mg(TFSI)₂ in polyethylene oxide (PEO) and a Li bis(trifluoromethane)sulfonimide (LiTFSI) formulae. As confirmed by cryogenic transmission electron microscopy, the anode/electrolyte interface exhibited hybrids consisting of crystalline Mg, Li₂O, and Li dots embedded in an amorphous polymer electrolyte. The crystalline Mg dots guided the uniform Li nucleation and growth, inducing a smoother anode/electrolyte interface compared with the pristine electrolyte. With 1 wt% Mg(TFSI)₂ in the PEO-LiTFSI electrolyte, the Mg-modified electrolyte enabled the Li/Li symmetric cells with cycling performance of over 1700 and 1400 h at current densities of 0.1 and 0.2 mA cm⁻², respectively. Moreover, the full LFP/Li cells using the novel Mg-modified electrolyte delivered a cycling lifespan of over 450 cycles with negligible capacity loss.

全固态锂金属电池中均匀的锂（Li）沉积受阳极/电解质界面的影响很大。在此，通过在聚环氧乙烷（PEO）和Li双（三氟甲烷）磺酰亚胺（LiTFSI）分子式中从Mg（TFSI）₂进行简单的原位电化学还原Mg ²⁺来构建Mg改性界面。如通过低温透射电子显微镜所证实的，阳极/电解质界面表现出由结晶Mg，Li ₂ O和嵌入无定形聚合物电解质中的Li点组成的杂化物。结晶的Mg点引导均匀的Li成核和生长，与原始电解质相比，诱导出更平滑的阳极/电解质界面。含1 wt％的Mg（TFSI）₂在PEO-LiTFSI电解质中，Mg改性的电解质使Li / Li对称电池在电流密度分别为0.1和0.2 mA cm ^-2时的循环性能分别超过1700和1400 h 。此外，使用新型Mg改性电解质的完整LFP / Li电池可提供超过450个循环的循环寿命，而容量损失可忽略不计。