Solid polymer electrolytes are promising for solid-state lithium metal batteries due to their processability and interfacial compatibility. Poly(vinylidene fluoride)-based electrolytes with residual solvent are appealing, but their porous structure and limited ionic conductivity hinder application. This study proposes a phase regulation strategy using MoSe₂ sheets to create a dense composite electrolyte. The high dielectric constant optimizes solvation structures for high ionic conductivity and low activation energy. In-situ reactions generate Li₂Se, improving Coulombic efficiency and interfacial kinetics. Li||Li cells cycle robustly, and Li||LiNi₀.₈Co₀.₁Mn₀.₁O₂ full cells show practical performance at high rates, loadings, and in pouch cells.

Qian Wu, Mandi Fang, Shizhe Jiao, Siyuan Li, Shichao Zhang, Zeyu Shen, Shulan Mao, Jiale Mao, Jiahui Zhang, Yuanzhong Tan, Kang Shen, Jiaxing Lv, Wei Hu, Yi He, Yingying Lu