Recent Progress on the Low-Temperature Lithium Metal Batteries and Electrolytes (Invited review)

The emergence and development of lithium (Li) metal batteries shed light on satisfying the human desire for high-energy density beyond 400 Wh kg^-1. Great efforts are devoted to improving the safety and cyclability of such new-type batteries, and certain progress is successfully achieved. However, given the diversity of application scenarios, the practical applications of Li metal batteries still remain challenges, especially in extremely low temperatures. The drop in temperature largely reduces the capacity and lifespan of batteries due to sluggish Li-ion (Li⁺) transportation and uncontrollable Li plating behaviors. Recently, attention is gradually paid to Li metal batteries for low-temperature operation, where the explorations on high-performance low-temperature electrolytes emerge as a hot topic. In this review, the progress of low-temperature Li metal batteries is systematically summarized. The challenges and influences of low temperatures on Li metal batteries are concluded. Subsequently, the solutions to low-temperature Li metal batteries based on electrolyte engineering are reviewed and discussed. Additionally, the techniques for low-temperature characterizations are classified and discussed. Most importantly, the future development prospects of low-temperature Li metal batteries are proposed from sustainable perspectives.