Electrolytes for Low‐Temperature Lithium Batteries Based on Ternary Mixtures of Aliphatic Carbonates

Abstract

The low-temperature performance of lithium-ion cells is mainly limited by the electrolyte solution, which not only determines the ionic mobility between electrodes but also strongly affects the nature of surface films formed on the carbonaceous anode. The surface films provide kinetic stability to the electrode (toward electrolyte) and permit charge (electron) transfer across them, which in turn determine the cycle life and rate capability of lithium-ion cells. Aiming at enhancing low-temperature cell performance, we have studied electrolyte solutions based on different ratios of alkyl carbonate solvent mixtures, i.e., ethylene carbonate (EC), dimethyl carbonate (DMC), and diethyl carbonate (DEC), in terms of electrolyte conductivity, film resistance, film stability, and kinetics of lithium intercalation and deintercalation, at various temperatures. Electrolytes based on the ternary mixtures of EC, DEC, and DMC emerged as preferred combination compared to the binary analogues both in terms of conductivity and surface film characteristics, especially at low temperatures. These studies are further corroborated in sealed AA cells, which showed a synergistic effect of high durability from the DMC-based solutions and improved low-temperature performance from the DEC-based electrolytes.

Electrolyte and Solid-Electrolyte Interphase Layer in Lithium-Ion Batteries

“…The main categories of solvents used or studied for LIB's electrolytes are alkycarbonates, ethers, lactones, sulfones and nitriles. The physiscochemical properties of these solvents are collected in Table 1 [Hayashi et al, 1999;Hayashi et al, 1999;Smart et al, 1999;Wakihara, M., 1998;Geoffroy et al, 2000 ;Xu (2004); Abu-Lebdeh & Davidson, 2009].…”

High‐Performance Low‐Temperature Li+ Intercalation in Disordered Rock‐Salt Li–Cr–V Oxyfluorides

“…[11] At temperatures below À10 8C, the ionic mobility in the electrolyte solution and conductivity of the conventional binary carbonate electrolyte fall rapidly. [12] The optimization of the electrolyte formulations for different electrode materials at low temperatures still remains to be solved. Nevertheless, exploring new cathodem aterials with well-retaineds pecific energiesa tr educed temperatures is am ore decisive step towards broad applications of Li-ion batteries.…”

A critical review of thermal management models and solutions of lithium-ion batteries for the development of pure electric vehicles

“…Poor lithium-ion battery performance under cold climates is therefore studied [84,86,87] which can be summarised from four factors: 1) low conductivity of the electrolyte and solid electrolyte interface on the electrode surface [88,89]; 2) declined solid-state Li diffusivity [80,84]; 3) high polarisation of the graphite anode [76,90]; and 4) the sluggish kinetics and transport processes caused by increased charge-transfer resistance on the electrolyte-electrode interfaces [80,84]. Three contributing factors of a PHEV lithium-ion battery impact of low ambient temperature at -7°C and 0°C have been quantified [82].…”

“…High Rov also causes excessive gassing resulting in a loss of electrolyte, or even case rupturing if the internal pressure generated due to gassing exceeds the capacity of the relief valves. The problems could be solved by formulating [88,89] or replacing the chemical substances [93,94] inside the lithium-ion batteries, or seeking for viable battery preheating methods in order to avoid loss in energy and power capability [81,86] as well as severe battery degradation at sub-zero climates.…”