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

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_0.6Sr_0.4CoO_3−δ (LSC) enriched with high valence-state Co species and oxygen vacancies is developed as electronically conductive nanofillers embedded within ZnO/Zn₃N₂-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/Zn₃N₂ on PI nanofiber upon immediate detection of dendritic Li, which takes part in reconfiguring hierarchical SEI chemistry dominated by Li_xN_y/Li−Zn alloy inner layer and LiF outer layer, SSLMBs are further endowed with prolonged cycling lifespan and exceptional rate capability.