Lithio-Gel via Lithium Bonding: Mitigating Anode Failure by Blocking Crosstalk in Rechargeable Li–SOCl 2 Batteries

Li–SOCl2 secondary batteries are promising energy storage systems due to their exceptional energy density and robust safety performance under a wide range of temperatures. However, their practical application is hindered by the crosstalk of cathode-derived species and electrolyte volatility, which leads to rapid anode deterioration, poor reversibility, and limited cell life. To address these issues, we present an in situ formed quasi-solid-state gel electrolyte mediated through a lithium bond (Li-bond), which effectively suppresses the detrimental crosstalk and electrolyte volatilization. This design is achieved through the limited dissociation of fluorinated lithium salts in SOCl2, where the highly polarized additives promote the self-assembly of Li-bonding networks. Built upon the solvated chain-like structure of the conventional LiAlCl4–SOCl2 electrolyte, the Li-bonding promotes the formation of a stable lithio-gel electrolyte (LGE). Electrochemical tests demonstrate that the LGE mitigates the detrimental byproducts on Li deposits through restraining the crosstalk of cathode-derived species and significantly extends the cycle life of a limited Li anode (100 μm) at high areal capacities, maintaining a high areal capacity of 6 mAh cm–2 at a current density of 5 mA cm–2 for 60 cycles and achieving an active material capacity utilization of over 80% with 3000 mAh g–1 capacity for 80 stable cycles, which further enhances the practicality (minimizing Li anode excess). These findings underscore that a deeper understanding of electrolyte design in Li–SOCl2 systems can pave the way for a new paradigm of high energy density and longer-lasting rechargeable lithium metal batteries.