LiI-Coated\nLi-Sn Alloy Composite Anode for Lithium\nMetal Batteries with Solid Polymer Electrolyte

Lithium metal batteries with solid-state polymer electrolytes\nhave\ngarnered significant attention for their enhanced safety and high\nenergy density. However, dendrite growth and interfacial reactions\nwith lithium metal anodes impede their commercial viability. In this\nstudy, a LiI-coated SnLi alloy composite anode was proposed to address\nthese critical issues. The SnLi alloy provides nucleation sites, suppressing\ndendrite formation, while the LiI-enriched coating reduces side reactions\nwith the polymer electrolyte, minimizing lithium consumption. As a\nresult, a symmetrical cell with the fabricated LiI/SnLi anode and\nPVDF solid polymer electrolyte (SPE) exhibits a cycling life of 2500\nh. Furthermore, the LiFePO<sub>4</sub>|PVDF-SPE|LiI/SnLi battery cycles\nstably over 1000 cycles. When the cathode was replaced with LiNi<sub>0.6</sub>Co<sub>0.2</sub>Mn<sub>0.2</sub>O<sub>2</sub>, the battery\nmaintained 73.3% capacity over 600 cycles. Notably, this coin cell\nsustains a stable electrochemical performance even under a high loading\nof NCM622 (10.2 mg cm<sup>–2</sup>) and a low N/P ratio of\n4.8 over 150 cycles.