Cool batteries: What’s next?

Lithium-ion batteries (LIBs) often encounter performance decline issues in cold conditions when temperature significantly drops, despite being widely regarded as a leading battery technology. Functioning as a typical rocking-chair battery, lithium ions shuttle through the "blood" (the electrolyte) of LIBs between the graphite anode (the commonly-used negative electrode) and the intercalation compound cathode (positive electrode), where ion movement tends to slow down with decreasing temperature. Considering the relative maturity of electrode materials, researchers generally pay attention to the electrolyte and corresponding electrode/electrolyte interphase in order to accelerate ion transport. In light of significant advancements, we herein try to delineate and categorize the electrolyte engineering to depict what next can be done to build better batteries suitable for cooler temperatures in the near future. Specifically, advances in electrolyte engineering are summarized with the goal of improving ionic conductivity in bulk electrolyte, facilitating desolvation dynamics at the electrode/electrolyte interface, and accelerating ion movement across the interfacial film. Furthermore, viable strategies are outlined to understand the design principles of low-temperature electrolyte and inspire more endeavors to overcome the critical challenges faced by LIBs in extreme conditions.