Tris(2,2,2-trifluoroethyl) phosphite as an electrolyte additive for high-voltage lithium-ion batteries using lithium-rich layered oxide cathode

JOURNAL OF POWER SOURCES

卷:296

Article

Pires, Julie¹  Castets, Aurore²  Timperman, Laure¹  Santos-Pena, Jesus¹  Dumont, Erwan³  Levasseur, Stephane⁴  Tessier, Cecile³  Dedryvere, Remi²  Anouti, Meriem¹ 

[1] Univ Tours, Lab PCM2E EA 6299, F-37200 Tours, France

[2] Univ Pau & Pays Adour, IPREM, UMR CNRS 5254, F-64053 Pau 9, France

[3] SAFT, F-33074 Bordeaux, France

[4] UMICORE, B-1000 Brussels, Belgium

关键词: Li-rich-NMC;    Phosphite;    Additive;    Li-ion battery;    High-voltage;    Cathode activation;   

DOI  :  10.1016/j.jpowsour.2015.07.065

来源: Elsevier

【 摘 要 】

In this paper, we report positive effect of Tris(2,2,2-trifluoroethyl) phosphite MR) as additive during initial activation and cycling of Li-rich-NMC xLi(2)MnO(3)-(1 - x)LiMO2 (x >> 1; M = Ni, Co, Mn) cathode in EC/DMC + 1 M LiPF6 electrolyte. Firstly conductivity and viscosity of electrolyte with x wt.% TTFP; 0 wt.% < x < 20 wt.% were studied. From the electrochemical characterization using cyclic voltammetry, galvanostatic charge/discharge and EIS we show that TTFP passives aluminum current collector and the acts as oxygen scavenger during the extended activation plateau up 4.7 V vs. Li+/Li (up to 301 mAh g(-1) in charge). The beneficial effect of TTFP improves the long-term cycling stability of the cathode with more than 95% of initial capacity in Gr//Li-Rich -NMC full cell is maintained after 50 cycles at C rate. Finally, XPS analysis of Li-rich-NMC electrodes show presence of TTFP on the surface during cycling and confirm the presence of Mn3+ at the end of discharge. The convergence of all characterizations indicates that TTFP should act as a catalyst to several surface reactions which are beneficial to long cycling cell performances. (C) 2015 Elsevier B.V. All rights reserved.

【 授权许可】

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