Rational Design of Electrolyte Additives for Low-Temperature Lithium Metal Batteries

Lithium metal batteries (LMBs) are one of the most promising candidates for next-generation energy storage due to their high energy density. However, their practical use is limited by a major performance drop at low temperatures, because of high desolvation energy barriers and the uncontrolled growth of lithium dendrites, which eventually leads to the formation of "dead lithium". This review aims to explain, from a mechanistic perspective, how electrolyte additives address these challenges at low temperatures. A clear mechanistic understanding is achieved by classifying modern additives into four behavioral types: decomposition, sustained-release, suspension, and adsorption. We also focus on how advanced tools are utilized to see these hidden interfacial processes in their native state. Finally, we propose a multidimensional design framework that combines orbital engineering, entropy regulation, and mechanical toughness. Translating these molecular-level insights into macroscopic interfacial stability gives way to accelerating the realization of reliable, extreme-condition lithium metal batteries.