Talcum-doped composite separator with superior wettability and heatproof properties for high-rate lithium metal batteries

• Published in: 中国化学快报（英文版） 2023, Vol.34 (1), p.139-144
• Main Authors: Mengqiu Yang, Yuanpeng Ji, Yunfa Dong, Botao Yuan, Liwei Dong, Yuanpeng Liu, Sue Hao, Chunhui Yang, Xiaoqiang Wu, Qingquan Kong, Jiecai Han, Weidong He
• Format: Article
• Language: English
• ISSN: 1001-8417

Separator is supposed to own outstanding thermal stability,superior wettability and electrolyte uptake,which is essential for developing high-rate and safe lithium metal batteries(LMBs).However,commercial polyolefin separators possess poor wettability and limited electrolyte uptake.For addressing this issue,we put forward a composite separator to implement above functions by doping layered-silicate(talcum)into polyvinylidene fluoride(PVDF).With significant improvement of electrolyte absorption benefiting from the strong adsorption energy values(-1.64～-1.70 eV)between talcum and the electrolyte in lithium metal batteries,PVDF/Talcum(PVDF/TM)composite separator owns a small contact angle and superior electrolyte uptake.PVDF/TM composite separator with 10 wt％talcum(T-10)owns a tiny contact angle of 8°,while those of polypropylene(PP)and PVDF are 48° and 20° with commercial electrolyte.Moreover,the addition of thermotolerant talcum endows the T-10 composite separator with great thermostability,whose thermal shrinkage is only 5.39％at 150℃for 0.5 h.The cell with LiFeO4 cathode and the T-10 composite separator reaches 91.7 mAh/g in discharge capacity at 4.8mA/cm2(10 C),far superior to that with pure PVDF separator(56.3 mAh/g)and PP(51.4 mAh/g).