Graphite (Gr) anode, which is endowed with high electronic conductivity and low volume expansion after Li-ion intercalation, establishes the basis for the success of rocking-chair Li-ion batteries (LIBs). However, due to the high barrier of the Li-ion desolvation process, sluggish transport of Li ions through the solid electrolyte interphase (SEI) and the high freezing points of electrolytes, the Gr anode still suffers from great loss of capacity and severe polarization at low temperature. Here, 1,2-diethoxyethane (DEE) with an intrinsically wide liquid region and weak solvation ability is applied as an electrolyte solvent for LIBs. By rationally designing the additives of electrolytes, an intact SEI with fast Li-ion conductivity is constructed, enabling the co-intercalation-free Gr anode with long-term stability (91.8% after 500 cycles) and impressive low-temperature characteristics (82.6% capacity retention at -20 °C). Coupled with LiFePO4 and LiNi0.8Mn0.1Co0.1O2 cathodes, the optimized electrolyte also demonstrates low polarization under -20 °C. Our work offers a feasible approach to enable ether-based electrolytes for low-temperature LIBs.
Keywords: ether-based electrolyte; graphite anode; interphase design; lithium-ion batteries; low temperature.