Novel Low-Temperature Electrolyte for Li-Ion Battery

In order to overcome the limitation of Li-ion batteries at low temperature, series of electrolytes are prepared. Specially，FEC is chose to work as electrolyte solvent to enhance its poor performance. Electrolytes are composed of EC, PC, EMC and FEC, while VC is added as additive. Electrolytes with different ratio are examined, then the electrolyte with the best conductivity is studied in detail. Its characters are evaluated by CV, EIS and charge/discharge tests et al. The discharge curves of LiCo 1/3 Ni 1/3 Mn 1/3 O 2 /Li show that battery with this FEC-based electrolyte at 233K could yield 51% of room temperature capacity. Most obviously, MCMB/Li half cell with this electrolyte could fill 91% of its normal capacity at 233K while batteries barely charge any with traditional electrolyte（LiPF6/EC+DMC(1:1 in volume)）. This nice charge behavior won’t emerge unless the conductivity could basically meet the demand at 233K. The property of FEC-based electrolyte outweighs commercialized electrolyte as this article confirms.