Highly stable lithium-ion wide-temperature storage performance achieved via anion-dominated solvation structure and electric double-layer engineering

The stable service of lithium-ion electrolyte is important for its application in the wide-temperature region. However, the reversible deposition of lithium at wide temperatures is limited due to the instability of the ion-solvation structure. Herein, adjusting the solvation structure is an effective strategy to solve this problem. With this idea, we use fluorinated solvents to tame stability between solvents and lithium ions. By regulating types of anions, a double-layer structure with low desolvation energy is constructed to improve ion diffusion. Furthermore, an anion-dominated solvation structure can form an inorganic-riched solid electrolyte interface layer to inhibit the decomposition of solvents and high-temperature performance is ensured. As a result, lithium metal batteries using lithium titanate can maintain stability in a wide temperature range of −55 to 60°C. In detail, the battery can maintain 70% of room temperature capacity at −35°C, while maintaining a capacity retention of 95% after 100 cycles. And its high-temperature performance also guaranteed capacity retention of 92% after 500 cycles at 60°C. This work provides a feasible way for electrolytes over a wide temperature range, namely, regulating dual anions to participate in the desolvation process, so that electrolytes can achieve low-temperature performance and high-temperature stability simultaneously.