Skeleton-flesh shape of multipath Li+ transport and compatible interfacial composite solid electrolyte for stable Li-metal batteries

All solid-state battery (ASSB) as the breakthrough of the advanced lithium-ions battery owing to its superior energy density and safety. Solid electrolytes are required to possess excellent electrochemical and safety. However, the low ionic conductivity and the poor interfacial compatibility, respectively, limits the progress of polymer and ceramic electrolyte , which accelerate the development of composite solid electrolyte (CSE). Therefore, we demonstrate a hierarchy structure that PEO(polyethylene)-LLZO@NFPAN-SiO 2 , which consists of SiO 2 particles encapsulated nanofibers (in-situ hydrolyzed by TEOS) and flexible membrane of PEO-LLZO to synergistically elevate the performance of CSE. This CSE exhibits broad electrochemical window (6 V vs. Li) and strong ionic conductivity (3.3 × 10 −4  S cm −1 , 30 °C), and also shows robust strength (5.1 MPa). The assembled Li-symmetric cells exhibit superior cycling life of 1000 h, with an extremely modest over potential of 45 mV. The full cell exhibits excellent cycle stability, 102 mA h g −1 after 100 cycles at 0.5C, and a high initial Coulomb efficiency of 68 %. Skeleton-flesh structure is constructed by in-situ particle-embedded nanofiber and covered polymer, which strengthened mechanical capability, compatibility, inhibition of lithium dendrites , and introduced multi-Li + transport pathways, ensuring high safety and superior electrochemical performance for the applications of ASSBs.