Challenges of film-forming additives in low-temperature lithium-ion batteries: A review

As a representative of electrochemical energy storage devices, lithium-ion batteries' (LIBs) performance under different working conditions has been widely concerned. In general, the performance of LIBs at low temperatures decreases significantly, and related problems are aggravated, such as Li+ migration retardation, ion activation barrier increase, and Li dendrite growth. The solid electrolyte interface (SEI) between electrodes and electrolytes is the key to optimizing the internal dynamics of batteries. Functional additives can achieve functional regulation of SEI in trace amounts and with high efficiency. In this article, the challenges facing LIBs at low temperatures are systematically summarized, including low capacity, poor charge efficiency, Li dendrite problems, and ion diffusion, and important modification strategies are reviewed. Importantly, the film-forming additives are reclassified, and the film-forming mechanisms and advantages are discussed separately. Finally, the design points of different film-forming additives for low temperature applications are summarized, and research directions are prospected. The purpose of this paper is to dialectically discuss the mechanism and design of film-forming additives to promote the development and application of low-temperature LIBs.