Turning to improve performances under industrial requirements may be more meaningful for research itself.

No abstract

The high impedance of the solid electrolyte interphase (SEI) is one of the important factors that deteriorate the charge behavior of lithium-ion batteries (LIBs) at low temperatures, which hinders their practical application in portable electronic products and electric vehicles under extreme conditions. Based on this consideration, a LiF-rich SEI film with low impedance, using lithium difluorobis(oxalato)phosphate (LiDFBOP) as an electrolyte additive and a blank electrolyte without commercial additives, is constructed on a graphite surface. The decomposition mechanism of LiDFBOP is further deduced by density functional theory calculations. This additive inhibits the decomposition of the electrolyte and then forms a thin SEI film with more LiF. LiF, possessing high Young's modulus, makes the SEI film dense and stable. At the same time, more LiF/Li 2 CO 3 interfaces are formed to increase the ionic conductivity. Benefiting from the components and the structure of the SEI, the graphite/Li cells exhibit excellent cycling stability (ca. 85.5% initial capacity retention for 200 cycles at 1 C) and an impressive low-temperature performance (ca. 200% capacity for electrolytes without LiDFBOP at −20 °C). This work presents an effective strategy for developing a functional electrolyte to meet the requirement of LIBs with enhanced low-temperature performance.