Surface modified by SnI2 boosts Dendrite-Free all-solid-state lithium metal batteries

[Display omitted] •Iodinated hybrid Solid-Electrolyte-Interphase is constructed via in situ coating method.•Solid state electrolyte is utilized to improve the safety.•The modification by SnI2 can effectively suppress the growth of lithium dendrite.•ASSLB with modified lithium metal delivers improved electrochemical performance. Lithium metal is the most promising next-generation anode due to its extremely high theoretical specific capacity and lowest operation potential. However, the high reactivity of lithium brings about a series of side reactions and fast capacity decay. Moreover, the inevitably growth of lithium dendrite will cause short circuit or other safety issues. Here, an artificial mixed ionic/electronic SEI (solid electrolyte interphase) is designed by treating the lithium anode with SnI2 solution in a simple drop coating method. The artificial SEI can inhibit the dendrite growth by forming nuclear agent sites and enable uniform current distribution. Solid state electrolyte is further utilized to improve the safety of battery. The symmetrical cells can cycle for > 750 h at 0.2 mA cm−2. Notably, all-solid-state LiFePO4 (LFP)/Li battery can deliver excellent capacity remains 120.6 mAh g−1 after 1000 cycles at 1C with a higher Coulombic efficiency at 99.8%. These results may be also useful for the developing of high energy and high safety lithium metal batteries.