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

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journal contribution
posted on 23.04.2018, 00:00 by Kai Jiang, Shu Gao, Ruxing Wang, Mao Jiang, Jing Han, Tiantian Gu, Mengyun Liu, Shijie Cheng, Kangli Wang
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.