Abstract:

Lithium-ion batteries (LIBs) are extensively used in various sectors including mobile devices, electric transportation, and energy storage systems. Their ability to reliably perform in cold environments—such as alpine regions, polar areas, and high-altitude or near-space environments critical to scientific exploration and military strategy—is of paramount importance. Electrolytes have a great influence on the low-temperature performance aspects of lithium-ion batteries. The high melting points and sluggish ion transfer of conventional carbonate electrolytes in cold conditions pose substantial challenges, often leading to reduced power output or even battery failure. Strategies such as introducing solvents with lower melting points, reducing the proportion of ethylene carbonate, or designing ethylene carbonate-free electrolytes have proven effective. These measures broaden the electrolyte's liquid range and enhance ionic conductivity, which in turn mitigates battery polarization and improves LIB performance at low temperatures. This paper first analyzes the failure mechanisms and lithium precipitation behavior of LIBs at low temperatures from the perspective of the electrolyte. Subsequently, it discusses research findings and modification strategies for low-temperature electrolytes over the past 5 years, including the selection of solvent molecules, lithium salts, and film-forming additives. This paper also introduces recent innovations in electrolyte design, such as high-entropy electrolytes, diluted high-concentration electrolytes, and weakly solvated electrolytes. Finally, it presents a comprehensive examination of the advantages, drawbacks, and scientific challenges associated with designing low-temperature electrolytes, culminating in proposed future research directions based on the current state of the field.

Key words: lithium-ion batteries, electrolyte, low temperatures, organic solvent