Brominated flame retardants coated separators for high-safety lithium-sulfur batteries
writer：Xinxin Dong , Tao Zhu
keywords：Brominated flame retardants，Lithium-sulfur batteries，Coating modified separator，Battery safety
source：期刊
Issue time：2023年
Lithium-sulfur batteries (LSBs) have become highly promising next-generation secondary lithium batteries owing to their high theoretical energy density and abundance of sulfur. Nevertheless, the large-scale application of LSBs is still restricted by the shuttle effect of lithium polysulfide (LiPSs) and the potential fire hazard caused by flammable electrolytes. Herein, three electrolyte-insoluble brominated flame retardants (BFRs) are selected and coated on both sides of commercial polypropylene separators by a facile slurry coating method. The effects of the three BFRs on the safety and electrochemical properties of LSBs are characterized and compared. The coating modification separators greatly improves the flame retardancy of LSBs through radical elimination mechanism. The self-extinguishing time of the electrolyte is reduced from 0.66 s/mg to 0.20 s/mg. Moreover, it is demonstrated that the oxygen (O)-containing BFRs exert a significant adsorption capacity and are more advantageous than O-free BFRs in LSBs. In addition, octabromoether (BDDP) coated separator is more effective in trapping LiPSs than decabromodiphenyl ether (DBDPO) due to higher O content, which can mitigate the shuttle effect and enhance the cycle and rate performance of LSBs. This simple coating strategy for separators with BFRs offers a strongly competitive option for the large-scale production of high-safety LSBs.
高安全性鋰硫電池溴化阻燃涂層隔膜
鋰硫電池（LSB）由于其高理論能量密度和豐富的硫而成為極具前景的下一代二次鋰電池。盡管如此，LSBs的大規(guī)模應用仍然受到多硫化鋰（LiPSs）的穿梭效應和易燃電解質引起的潛在火災隱患的限制。在此，選擇了三種電解質不溶性溴化阻燃劑 (BFR) 并將其涂覆在商用聚丙烯的兩面通過簡便的漿料涂覆方法分離器。表征并比較了三種 BFR 對 LSB 的安全性和電化學性能的影響。涂層改性隔膜通過自由基消除機制大大提高了 LSB 的阻燃性。電解液的自熄時間從0.66 s/mg減少到0.20 s/mg。此外，研究表明，含氧 (O) 的 BFRs 具有顯著的吸附能力，并且在 LSB 中比不含 O 的 BFRs 更有優(yōu)勢。此外，由于 O 含量較高，八溴醚 (BDDP) 涂層隔膜比十溴二苯醚 (DBDPO) 更有效地捕獲 LiPS，這可以減輕穿梭效應并提高 LSB 的循環(huán)和倍率性能。