Facilely solving cathode/electrolyte interfacial issue for high-voltage lithium ion batteries by constructing an effective solid electrolyte interface film

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• 作者：Jingjing Xu^a ; Qingbo Xia^a ; ^b ; Fangyuan Chen^a ; ^b ; Tao Liu^a ; Li Li^a ; ^b ; Xueyuan Cheng^a ; ^b ; Wei Lu^a ; Xiaodong Wu^a ; ^{xdwu2011@sinano.ac.cn" class="auth_mail" title="E-mail the corresponding author}
• 关键词：High-voltage Lithium ion batteries ; Cyclic performance ; Solid electrolyte interphase (SEI) ; Oxidable additive ; Cathode/electrolyte interface
• 刊名：Electrochimica Acta
• 出版年：2016
• 出版时间：10 February 2016
• 年：2016
• 卷：191
• 期：Complete
• 页码：687-694
• 全文大小：2338 K

文摘

The cathode/electrolyte interface stability is the key factor for the cyclic performance and the safety performance of lithium ion batteries. Suppression of consuming key elements in the electrode materials is essential in this concern. In this purpose, we investigate a facile strategy to solve interfacial issue for high-voltage lithium ion batteries by adding an oxidable fluorinated phosphate, Bis(2,2,2-trifluoroethyl) Phosphite (BTFEP), as a sacrificial additive in electrolyte. We demonstrate that BTFEP additive could be oxidized at slightly above 4.28 V which is a relatively lower voltage than that of solvents, and the oxidative products facilitate in-situ forming a stable solid electrolyte interphase (SEI) film on the cathode surface. The results manifest the SEI film validly restrains the generation of HF and the interfacial side reaction between high-voltage charged LiNi_0.5Mn_1.5O₄ (LNMO) and electrolyte, hence, the dissolution of Mn and Ni is effectively suppressed. Finally, the cyclic performance of LNMO after 200 cycles was remarkably improved from 68.4% in blank electrolyte to 95% in 1 wt% BTFEP-adding electrolyte.