Regulating\nthe Molecular Interactions in Polymer Binder\nfor High-Performance Lithium–Sulfur Batteries

Abstract

Polymer\nbinders have been shown to efficiently conquer the notorious\nlithium polysulfide (LiPS) shuttle effects in lithium–sulfur\n(Li–S) batteries for years, but more study is needed. Herein,\na water dispersible and molecular interaction regulated polymer binder\n(PNAVS) for Li–S batteries was elaborately designed by co-polymerizing <i>N</i>-acryloyl glycinamide and 3-(1-vinyl-3-imidazolio)­propanesulfonate.\nWe demonstrate that by modulating the multiple interactions between\nthe functional groups through copolymerization the binder was able\nto coordinate the LiPSs with higher binding energy for shuttle effect\nalleviation and cycling performance improvement. In addition, the\nLi⁺ diffusion coefficient is also optimized in the PNAVS\nbinder, which facilitates acceleration of the redox kinetics during\ncycling. Consequently, the PNAVS binder renders the Li–S battery\nwith an ultrastable open circuit voltage for more than 3000 h. Even\nwith a high sulfur loading of 11.7 mg cm^–2, the\nbattery can still exhibit excellent areal capacity of 12.21 mA h cm^–2. As proof of concept, a pouch cell was also demonstrated\nwith the stable cycling performance for 110 cycles. The binder engineering\nstrategy in this work will propel the practical applications of high-performance\nbatteries.