Lithium Sulfonate/Carboxylate-Anchored Polyvinyl Alcohol Separators for Lithium Sulfur Batteries

• DOI: 10.1021/acsami.8b03290
• Publication Date: 2018-04-23T12:25:16Z
• Authors: Kai Jiang; Shu Gao; Ruxing Wang; Mao Jiang; Jing Han; Tiantian Gu; Mengyun Liu; Shijie Cheng; Kangli Wang
• Keywords: 02 engineering and technology; 0210 nano-technology; 7. Clean energy

A monolayer poly(vinyl alcohol) (PVA)-based separator with pendant sulfonate/carboxylate groups and compact morphology is synthesized to suppress the essential lithium polysulfide permeation in lithium sulfur batteries (LSBs). The Li+ transference number is significantly increased to 0.8, much higher than that of a commercial separator (0.43). The polysulfide retention is verified by idle test in a polysulfide-rich electrolyte under the internal electric field of the cell. The LSB with an additive-free electrolyte attains a Coulombic efficiency around 98% and delivered capacity of 804 mA h g-1 at 2.5 A g-1. After 500 cycles, it retains 901 mA h g-1 at 1.5 A g-1 with extra low fading rate of 0.016% per cycle. Overall, this monolayer PVA-based separator provides a facile and effective technique to assemble highly stable LSBs.