Lithium difluorophosphate as an additive to improve the low temperature performance of LiNi0.5Co0.2Mn0.3O2/graphite cells. (10th December 2016)

• Record Type: Journal Article
• Authors: Yang, Bowen; Zhang, Hong; Yu, Le; Fan, WeiZhen; Huang, Donghai
• Is Part Of: Electrochimica acta. Volume 221(2016)
• Page Start: 107
• Page End: 114
• Publication Date: 2016-12-10
• Subjects: Lithium difluorophosphate -- electrolyte additive -- low temperature -- LiNi0.5Co0.2Mn0.3O2/graphite cells; Electrochemistry -- Periodicals; Electrochemistry, Industrial -- Periodicals; 541.37
• DOI: 10.1016/j.electacta.2016.10.037
• Languages: English
• ISSNs: 0013-4686

Abstract

Abstract: Lithium difluorophosphate (LiPO2 F2 ) was used as an electrolyte additive to promote the low temperature performance of LiNi0.5 Co0.2 Mn0.3 O2 /graphite cells. The impact of LiPO2 F2 on the solid electrolyte interface (SEI) film-formation on electrodes was demonstrated by various electrochemical methods and microscopy techniques, such as transmission electron microscopy (TEM), scanning electron microscope (SEM) as well as X-ray photoelectron spectroscopy (XPS), in the pouch cells and half cells. The results showed that the cells containing 1% LiPO2 F2 performed 71.9% (−20 °C) and 57.93% (−30 °C) of initial capacity, while the cells without LiPO2 F2 discharged only 49.41% and 9.6% of initial capacity under the same condition. In addition, the enhancement of cyclic performance at 0 °C was attributed to a conductive and stable SEI film formed on the graphite by the sacrifice of LiPO2 F2, which led to a low impedance and richer content of LiF and Li2 CO3 in SEI components, as depicted in XPS.