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An Electronegative Modified Separator with Semifused Pores as a Selective Barrier for Highly Stable Lithium–Sulfur Batteries

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journal contribution
posted on 19.07.2019, 22:13 by Junxiao Wang, Mengjia Li, Chong Liu, Yong Liu, Tongkun Zhao, Pengfei Zhai, Jingtao Wang
The rapid capacity fading and poor cycling life caused by polysulfide shuttle severely limit the development of high-energy-density lithium–sulfur batteries. Herein, a new type of electronegative modified separator with semifused pores is designed to suppress polysulfide shuttle and simultaneously elevate Li+ conduction. This separator is facilely prepared by lithiation of Nafion/poly­(acrylic acid) electrospun fiber mat on a commercial separator. Abundant electronegative groups on the separator strongly repel anionic polysulfides, effectively inhibiting the shuttle effect. Moreover, these groups provide numerous sites for Li+ transfer, and meanwhile the semifused pores work as low-barrier transport pathways, jointly facilitating Li+ conduction. Therefore, the battery exhibits outstanding cycling stability (decay rate of 0.023% per cycle during 1000 cycles at 1.0 C) and decent rate capability (discharge capacity of 730 mAh g–1 even at 3.0 C). Additionally, the sulfonated poly­(ether ether ketone) is taken as an example to verify the universality of this design strategy.