In Situ Formation of a Lithiophilic Li-Zn Alloy Using Dual-Salt Electrolyte Additives for Lithium Metal Batteries.

Abstract

The highly reactive nature of Li metal presents challenges, such as an unstable solid-electrolyte interphase (SEI) and uneven Li nucleation. Herein, to address these challenges, ZnF₂ and LiNO₃ were introduced as electrolyte additives to create a lithiophilic Li-Zn alloy and a stable SEI comprising LiF and LiNO₃ on the Li metal surface. The Li-Zn alloy, formed via a spontaneous conversion reaction between ZnF₂ and Li, provides favorable nucleation sites for Li deposition, thereby suppressing dendrite growth and improving the cycle stability of the Li metal, even at a high current density of 5 mA cm^-2. In Li||LiFePO₄ full cells, a remarkable capacity retention of 98.6% was achieved after 400 cycles at 1 C. Furthermore, approximately 100% capacity retention was achieved after 1400 cycles at 10 C. This study provides a simple and effective electrolyte additive strategy for obtaining dendrite-free Li metal.