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Wide-Temperature Electrolytes for Lithium-Ion Batteries

Qiuyan Li, Shuhong Jiao, Langli Luo, Michael S Ding, Jianming Zheng, Samuel S Cartmell, Chong-Min Wang, Kang Xu, Ji-Guang Zhang, Wu Xu

ACS Appl Mater Interfaces. 2017 Jun 7;9(22):18826-18835.

PMID: 28523915

Abstract:

Formulating electrolytes with solvents of low freezing points and high dielectric constants is a direct approach to extend the service-temperature range of lithium (Li)-ion batteries (LIBs). In this study, we report such wide-temperature electrolyte formulations by optimizing the ethylene carbonate (EC) content in the ternary solvent system of EC, propylene carbonate (PC), and ethyl methyl carbonate (EMC) with LiPF6 salt and CsPF6 additive. An extended service-temperature range from -40 to 60 °C was obtained in LIBs with lithium nickel cobalt aluminum oxide (LiNi0.80Co0.15Al0.05O2, NCA) as cathode and graphite as anode. The discharge capacities at low temperatures and the cycle life at room temperature and elevated temperatures were systematically investigated together with the ionic conductivity and phase-transition behaviors. The most promising electrolyte formulation was identified as 1.0 M LiPF6 in EC-PC-EMC (1:1:8 by wt) with 0.05 M CsPF6, which was demonstrated in both coin cells of graphite∥NCA and 1 Ah pouch cells of graphite∥LiNi1/3Mn1/3Co1/3O2. This optimized electrolyte enables excellent wide-temperature performances, as evidenced by the high capacity retention (68%) at -40 °C and C/5 rate, significantly higher than that (20%) of the conventional LIB electrolyte, and the nearly identical stable cycle life as the conventional LIB electrolyte at room temperature and elevated temperatures up to 60 °C.

Chemicals Related in the Paper:

Catalog Number Product Name Structure CAS Number Price
AP1333886 Cobalt aluminum oxide Cobalt aluminum oxide 1333-88-6 Price
AP623530 Ethyl methyl carbonate Ethyl methyl carbonate 623-53-0 Price
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