Synergistic Regulation of Electrolyte Composition and Electrode Interface for Enhanced Low-Temperature Performance of Lithium-Ion Batteries

Lithium-ion batteries hold enormous potential for applications in diverse fields, including electric vehicles, aerospace engineering, and 3C consumer electronics. However, their practical deployment is limited by a narrow operating temperature range. To address this challenge, we develop a systematic strategy focusing on both electrolyte engineering and interface modification for improved low-temperature conditions. Our electrolyte design employs methyl propionate as the primary solvent due to its low freezing point, complemented by fluoroethylene carbonate (FEC) as a film-forming additive and bis(2,2,2-trifluoroethyl) ether (BTFE) as the diluent to regulate the Li+ solvation structure. This synergistic formation enables the formation of a passivation layer (e.g., LiF and Li2CO3) on the electrode surface, which effectively reduces the low-temperature interface impedance and enhances charge transfer. Through the synergistic effects of FEC and BTFE, the optimized electrolyte exhibits considerable cycling performance at room temperature in both NCM523||Li and graphite||Li half-cells. Furthermore, the NCM523||graphite full cell delivers satisfactory cycling performance at both RT and –20 °C. Notably, it retains approximately 60% of its RT capacity (90.5 mAh g−1 even at –40 °C and 0.1 C)), which is supported by the high discharge capacities of 104.5 and 245.2 mAh g−1 from NCM523/Li and graphite/Li half cells, respectively, under the same extreme conditions. In summary, this study demonstrates a rationally designed electrolyte system that synergistically enhances the low-temperature performance and cycling stability of LIBs through tailored solvation structure and robust interphase engineering, offering a viable pathway for their application in extreme environments.