Lipoic Acid-Derived Interphase for Stable Lithium Metal Anodes in High-Performance Lithium Metal Batteries

Lithium metal batteries are widely regarded as one of the most promising candidates for achieving energy densities beyond 500 Wh kg−1. However, their practical commercialization is severely hindered by the high reactivity of lithium metal, which leads to pronounced interfacial instability. Constructing an artificial solid electrolyte interphase (SEI) via surface pretreatment has been demonstrated to be an effective strategy for suppressing dendrite growth and mitigating parasitic side reactions. Herein, we take advantage of the rapid reaction between lipoic acid (LA) and lithium metal to pre-form a uniform artificial SEI on the anode surface. This interphase is composed of organic COO-Li species and sulfur-containing compounds. Electrochemically, the LA-modified lithium anode exhibits remarkable stability, sustaining more than 1500 h of cycling in symmetric cells at 5 mA cm−2 and 5 mAh cm−2. Furthermore, full-cell configurations, including lithium-sulfur and lithium-LiFePO4 pouch cells, deliver significantly improved cycling performance compared with those employing bare lithium anodes. These results establish a practical and scalable route for fabricating stable artificial SEI layers on lithium metal, thereby providing a feasible pathway toward the realization of high-energy-density lithium metal batteries.