The electrolyte generally dictates the working temperature range of lithium-ion batteries (LIBs), thus developing a new class of electrolytes (primarily functional additives) in LIBs for wide temperature applications will be quite essential for further development of LIBs for the electric vehicle market. In this study, we develop new functional electrolytes containing multiple additives to enable the LIBs to perform well in a wide temperature range from -40 to 60 °C. Importantly, those cells based on the above optimized electrolytes have been proven to behave significantly enhanced discharging performance at -40 °C, the long-term cycling stability at 25 °C (more than 85% of capacity retention after 1000 cycles at 1C/1C rates in 1 Ah pouch cells), as well as the obviously improved cycling stability at 60 °C. These remarkable cell performances originate from the highly conductive, uniform, and compact passivating films formed on both anode and cathode surfaces by the synergistic effects of the multiple additives. Our finding on the synergistic benefits originating from a certain additive combination in the optimized electrolytes would favorably widen the working temperature range of future high-performance LIBs.
Keywords: additive; electrode/electrolyte interphase; electrolyte; lithium-ion battery; wide temperature.