Electrolyte additives for extending the operational temperature range of rechargeable lithium batteries
Rechargeable lithium batteries (LBs) capable of withstanding extreme high and low temperatures (HT/LT) are indispensable for carbon neutrality, yet commercial cells deliver only 80% of room-temperature capacity at −20 °C and 90% at 55 °C. This review systematically examines the failure mechanisms of electrolytes under HT/LT conditions, including thermally driven side reactions, LiPF6 hydrolysis generating corrosive HF, transition-metal dissolution, sluggish Li+ desolvation, and unstable solid electrolyte interphase (SEI) formation. Electrolyte additives, characterized by small dosage, low cost, and minimal energy-density penalty, are classified by their working mechanisms, functions, advantages, and disadvantages. Design principles for advanced additives are proposed, emphasizing synergistic optimization of oxidative stability at HT and ion mobility at LT. Although tailored to lithium-based systems, the strategies offer transferable insights for sodium and potassium batteries facing temperature-dependent degradation. Key empirical benchmarks from the literature include nitrile-based passivation layers, localized high-concentration electrolytes with lithium nitrate, and polymer-like glass-forming electrolytes enabling fast ion transport at low temperatures. The review consolidates 130 references, providing a rigorous framework for additive selection and interface engineering to extend operational temperature ranges.