Competitive Anion Anchoring and Hydrogen Bonding in Multiscale‐Coupling Composite Quasi‐Solid Electrolytes for Fire‐Safety and Long‐Life Lithium Metal Batteries

Abstract Composite solid‐state electrolytes (CSEs) using Li 1+x Al x Ti 2‐x (PO 4 ) 3 (LATP) as active fillers offer promising prospects for large‐scale lithium metal batteries (LMBs) applications due to their high environmental stability, cost‐effectiveness, and improved safety. However, the challenges persist owing to high interfacial resistance with electrodes and instability with lithium metal. Herein, self‐assembly nanofiber/polymers/LATP composite quasi‐solid electrolytes (SL‐CQSEs) are reported through in situ polymerization of precursor solution containing vinylene carbonate (VC), fluoroethylene carbonate (FEC), lithium bis(trifluoromethanesulfonic) imide (LiTFSI) in a porous and flexible self‐supporting skeleton (SSK) consisting of 2‐(3‐(6‐methyl‐4‐oxo‐1,4‐dihydropyrimidin‐2‐yl)ureido)ethyl methacrylate (UPyMA)’s self‐assembly nanofiber (SAF), poly(vinylidene fluoride‐co‐hexafluoropropylene) (PVDF‐HFP) and LATP. Anion‐anchoring/hydrogen‐bonding competition and intercomponent multiscale‐coupling effects on SL‐CQSEs are found, which contribute to their incombustibility, excellent room‐temperature ionic conductivity (1.03 mS cm −1 ), wide electrochemical window (5.1 V), good interfacial compatibility, and lasting inhibition of lithium dendrites. LiFePO 4 /Li cells with SL‐CQSEs not only exhibit high‐rate performance and long‐term cycling stability, with a capacity retention of 90.4% at 1C and 87% even at 4C after 1000 cycles, but also can resist fire and mechanical abuse, highlighting the potential applications of SL‐CQSEs for high‐performance and safety LMBs.