Tris(trimethylsilyl)phosphate: A film-forming additive for high voltage cathode material in lithium-ion batteries

• Published in: Journal of power sources Vol. 248; pp. 1306 - 1311
• Main Authors: Yan, Guochun, Li, Xinhai, Wang, Zhixing, Guo, Huajun, Wang, Chao
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier 2014
• Subjects: Additives; Applied sciences; Cathodes; Cut-off; Cycles; Direct energy conversion and energy accumulation; Electrical engineering. Electrical power engineering; Electrical power engineering; Electrochemical conversion: primary and secondary batteries, fuel cells; Electrochemical impedance spectroscopy; Electrolytes; Exact sciences and technology; High voltages; Lithium-ion batteries; Materials; X-ray photoelectron spectroscopy; Phosphates; Lithium ion batteries; Cobalt Oxides; Cathode; Nickel Oxides; Lithium Oxides; Film formation; Secondary cell; Tris(trimethylsilyl)phosphate; Electrode material; Phosphorus Compounds; Additive; Inorganic anion; High voltage; Lithium nickel cobalt manganese oxide; Manganese Oxides; Film forming properties
• ISSN: 0378-7753
• DOI: 10.1016/j.jpowsour.2013.10.037

Tris(trimethylsilyl)phosphate (TMSP) is investigated as a novel film-forming additive for LiNi sub(0.5)Co sub(0.2)-Mn sub(0.3)O sub(2) cycling at high cut-off potential in LiPF sub(6)-based electrolyte. Linear sweep voltammetry (LSV) results reveal that TMSP oxidizes prior to the decomposition of carbonate solvents in electrolyte. When TMSP is incorporated into the electrolyte, the electrochemical performance of LiNi sub(0.5)Co sub(0.2)Mn sub(0.3)O sub(2) is enhanced significantly. The initial discharge capacity of LiNi sub(0.5)Co sub(0.3)Mn sub(0.3)O sub(2) cathode material cycling in the electrolyte with 1 % TMSP is increased from 173.4 to 191.0 mAh g super(-1) compared with that without TMSP between 3.0 and 4.5 V (vs. Li/Li super(+)) at 0.1 C(1 C = 170 mA g super(-1)). In addition, it exhibits a capacity-retention of 90.9% at 1 C after 100 cycles, while that without TMSP is 77.0%. TEM, XPS, and EIS analyses confirm that the film derived from TMSP protects LiNi sub(0.5)Co sub(0.2)Mn sub(0.3)O sub(2) material from eroding by HF effectively, and reduces the interface impedance.