Traditional lithium batteries cannot work well at low temperatures due to the sluggish desolvation process, which limits their applications in low-temperature fields. Among various previously reported approaches, solvation regulation of electrolytes is of great importance to overcome this obstacle. In this work, a tetrahydrofuran (THF)-based localized high-concentration electrolyte is reported, which possesses the advantages of a unique solvation structure and improved mobility, enabling a Li/lithium manganate (LMO) battery to cycle stably at room temperature (retains 85.9% after 300 cycles) and to work at a high rate (retains 69.0% at a 10C rate). Apart from that, this electrolyte demonstrates superior low-temperature performance, delivering over 70% capacity at -70 °C and maintaining 72.5 mAh g-1 (≈77.1%) capacity for 200 cycles at a 1C rate at -40 °C. Also, even when the rate increases to 5C, the battery could still operate well at -40 °C. This work demonstrates that solvation regulation has a significant impact on the kinetics of cells at low temperatures and provides a design method for future electrolyte design.
Keywords: fast kinetics; localized high-concentration electrolyte; low temperature; solvation structure; tetrahydrofuran.