Enhanced low-temperature resistance of lithium-ion batteries based on methyl propionate-fluorinated ethylene carbonate electrolyte

Abstract

Low temperature has been a major challenge for lithium-ion batteries to maintain satisfied electrochemical performance, as it leads to poor rechargeability and low capacity retention. Commercial electrolytes of lithium-ion battery rely heavily on ethylene carbonate (EC), and its high melting point (36.4 °C) severely limits the use of batteries below 0 °C. In this work, we demonstrate that using the low melting point carboxylate of methyl propionate (MP) and vinyl fluorocarbonate (FEC) based electrolyte can overcome the low-temperature cycle limitation. Compared with carbonate electrolytes, MP has lower binding energy with Li+, which is essential to improve the low-temperature performance of the battery, and FEC is an effective component to inhibit the side reaction with the electrode of lithium metal. The carefully formulated MP-based electrolyte can generate a solid electrolyte interface with low resistance and rich in inorganic substances, which is conducive to the smooth diffusion of Li+, allowing the battery to successfully cycle at a high rate of 0.5 C at -20 °C, and giving it a reversible capacity retention rate of 65.3% at -40 °C. This work designs a promising advanced electrolyte and holds the potential to overcome limitations of lithium-ion batteries in harsh conditions.