Revealing the Influence of Electron Migration Inside Polymer Electrolyte on Li+ Transport and Interphase Reconfiguration for Li Metal Batteries

Abstract The development of highly producible and interfacial compatible in situ polymerized electrolytes for solid‐state lithium metal batteries (SSLMBs) have been plagued by insufficient transport kinetics and uncontrollable dendrite propagation. Herein, we seek to explore a rationally designed nanofiber architecture to balance all the criteria of SSLMBs, in which La 0.6 Sr 0.4 CoO 3−δ (LSC) enriched with high valence‐state Co species and oxygen vacancies is developed as electronically conductive nanofillers embedded within ZnO/Zn 3 N 2 ‐functionalized polyimide (Zn‐PI) nanofiber framework for the first time, to establish Li + transport highways for poly vinylene carbonate (PVC) electrolyte and eliminate nonuniform Li deposits. Revealed by characterization and theoretical calculation under electric field, the positive‐negative electrical dipole layer in LSC derived from electron migration between Co and O atoms aids in accelerating Li + diffusion kinetics through densified electric field around filler particle, featuring a remarkable ionic conductivity of 1.50 mS cm −1 at 25 °C and a high Li + transference number of 0.91 without the risk of electron leakage. Integrating with the preferential sacrifice of ZnO/Zn 3 N 2 on PI nanofiber upon immediate detection of dendritic Li, which takes part in reconfiguring hierarchical SEI chemistry dominated by Li x N y /Li−Zn alloy inner layer and LiF outer layer, SSLMBs are further endowed with prolonged cycling lifespan and exceptional rate capability.