TTFP在锂离子蓄电池电解液中的阻燃性能

Tris(2,2,2-trifluoroethyl) phosphite as a flame-retardant additive in electrolytes for Li-ion batteries

为了研究三(2,2,2-三氟乙基)亚磷酸酯(TTFP)作为锂离子蓄电池电解液阻燃剂的阻燃效果及其对电池电性能的影响,采用自熄时间(SET)法测试了TTFP对1mol/LLiPF6+EC/DMC(1∶1w/w)锂离子蓄电池电解液的阻燃性能;采用测电导率的方法研究了TTFP对电解液电导率的影响,并分别以其作为Li/LiCoO2、Li/MCMB和MCMB/LiCoO2电池的电解液阻燃添加剂分析了TTFP在MCMB负极、LiCoO2正极上的电化学稳定性及其对电池电性能的影响。研究结果表明,TTFP可显著降低电池电解液的可燃性,电解液的可燃性随着电解液中TTFP含量的增大而迅速降低,电解液的电导率也降低,当TTFP浓度为20%(质量百分数,以下同)时,电解液的SET几乎为零,电解液电导率的下降幅度与电解液中TTFP的浓度呈线性关系。TTFP在MCMB负极材料和LiCoO2正极材料上的电化学稳定性良好。TTFP不但对MCMB/LiCoO2电池的电化学性能的影响很小,而且能够明显提高其安全性能。研究结果对于开发锂离子蓄电池电解液新型阻燃剂和提高锂离子蓄电池的安全性能具有一定的理论意义和实用价值。

The paper investigated the effect of tris（2,2,2-trifluoroethyl） phosphite （TTFP） on the flammability and conductivity of the electrolyte, as well as the cell performance. The SET （Self-Extinguishing Time） and conductivity results show that the flammability of the electrolyte can be rapidly reduced while the ionic conductivity of the electrolyte decreased slowly as the TTFP content increasing, and the electrolyte becomes almost nonflammable when the TTFP content reaches 20%. The performance of Li/LiCoO2 and Li/MCMB half-cell indicate that the TTFP has good electrochemical stability on LiCoO2 cathode and MCMB anode. Also the TTFP can obviously improve the safety of the MCMB/LiCoO2 cell but has negligible adverse impact on its cycling performance.