Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
7725901 | Journal of Power Sources | 2018 | 10 Pages |
Abstract
With the wide application of lithium-ion batteries (LiBs), safety performance is an important constraint on the commercialization of large-scale, high-capacity LIBs. The main reason for the safety problem is that the electrolyte of LiBs is highly flammable, especially under high temperature and high voltage. It is an effective method to improve the safety of cells by mixing flame retardant with conventional electrolyte comprising of LiPF6 and carbonates. Herein, ethoxy (pentafluoro) cyclotriphosphazene (PFPN) is studied as a high efficiency flame retardant. Adding 5â¯vol% of PFPN results in a non-flammable electrolyte with self-extinguishing time (SET) of 12.38â¯sâ¯gâ1 and critical oxygen index (COI) of 22.9, without compromising the capacity of cathode material. The initial discharge capacity of the LiCoO2 electrode with 5% PFPN is 150.7â¯mAhâ¯gâ1, with a capacity retention of 99.14% after 30 cycles at 0.1â¯C. The results show that 5â¯vol% is the best adding amount of PFPN for electrolyte, which can modify the solid electrolyte interface (SEI). Moreover, PFPN reduces charge transfer resistance of the cells, resulting decreased electrode polarization and enhanced electrochemistry performances at low temperature. These results have confirmed that PFPN has the potential to be a multi-function additive for commercial LIBs production.
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Authors
Xi Li, Weikang Li, Lai Chen, Yun Lu, Yuefeng Su, Liying Bao, Jing Wang, Renjie Chen, Shi Chen, Feng Wu,