Investigation and application of lithium difluoro(oxalate)borate (LiDFOB) as additive to improve the thermal stability of electrolyte for lithium-ion batteries

• Published in: Journal of power sources Vol. 196; no. 16; pp. 6794 - 6801
• Main Authors: Xu, Mengqing, Zhou, Liu, Hao, Liansheng, Xing, Lidan, Li, Weishan, Lucht, Brett L.
• Format: Journal Article Conference Proceeding
• Language: English
• Published: Amsterdam Elsevier B.V 15.08.2011; Elsevier
• Subjects: Additives; Anodes; Applied sciences; Cathodes; Direct energy conversion and energy accumulation; Electrical engineering. Electrical power engineering; Electrical power engineering; Electrochemical conversion: primary and secondary batteries, fuel cells; Electrolyte additive; Electrolytes; Electrolytic cells; Elevated temperature; Exact sciences and technology; Lithium; Lithium difluoro(oxalate)borate; Lithium-ion batteries; Lithium-ion battery; Thermal stability; Lithium-ion battery; Elevated temperature; Electrolyte additive; Thermal stability; Lithium difluoro(oxalate)borate; Lithium battery; Additive; Lithium Borates; Electrolyte; Alkaline storage battery; Secondary cell; High temperature
• ISSN: 0378-7753; 1873-2755
• DOI: 10.1016/j.jpowsour.2010.10.050

Lithium difluoro (oxalate) borate (LiDFOB) is used as thermal stabilizing and solid electrolyte interface (SEI) formation additive for lithium-ion battery. The enhancements of electrolyte thermal stability and the SEIs on graphite anode and LiFePO 4 cathode with LiDFOB addition are investigated via a combination of electrochemical methods, nuclear magnetic resonance (NMR), X-ray photoelectron spectroscopy (XPS), Fourier transform infrared-attenuated total reflectance (FTIR-ATR), as well as density functional theory (DFT). It is found that cells with electrolyte containing 5% LiDFOB have better capacity retention than cells without LiDFOB. This improved performance is ascribed to the assistance of LiDFOB in forming better SEIs on anode and cathode and also the enhancement of the thermal stability of the electrolyte. LiDFOB-decomposition products are identified experimentally on the surface of the anode and cathode and supported by theoretical calculations.