Interfacial engineering of polypropylene separator with outstanding high-temperature stability for highly safe and stable lithium-sulfur batteries
Mao Sheng Yang, Jue Nan, Wei Chen, Anjun Hu, He Sun, Yuanfu Chen, Chunyang Wu
Abstract
The thermal shrinkage of commercial polypropylene (PP) separator at high temperature seriously restricts the development of safe and stable lithium-sulfur (Li-S) batteries. To address such issue, herein, we present an interfacial engineering strategy by coating conductive polypyrrole (PPY) modified lithium-montmorillonite (PPY/Li-MMT) on the PP separator. The PPY/Li-MMT can service as an effective heat release layer to enhance the high-temperature stability of Li-S batteries. The engineered PP separator exhibits superior performance: it shows nearly no thermal shrinkage even up to 150 °C. Most importantly, the interface engineered separator has not be punctured during the hot piercing testing and the Li-S batteries deliver outstanding thermal stability even at 80 °C. In addition, the PPY/Li-MMT modified PP separator owns very high electrolyte uptake of 348.6%, large ionic conductivity of 3.63 mS cm−1 and stable performance over 600 cycles. This work provides an effective interfacial engineering strategy by coating PPY/Li-MMT interlayer to significantly improve the electrochemical performance and particularly the high-temperature stability of Li-S batteries.