Gong Qi, Hou Lei, Li Tianyu, Jiao Yucong, Wu Peiyi
State Key Laboratory for Modification of Chemical Fibers and Polymer Materials, College of Chemistry Chemical Engineering and Biotechnology, Donghua University, Shanghai 201620, P.R. China.
Division of Energy Storage, Dalian National Laboratory for Clean Energy, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, P.R. China.
ACS Nano. 2022 May 24;16(5):8449-8460. doi: 10.1021/acsnano.2c03059. Epub 2022 May 11.
Polymer binders have been shown to efficiently conquer the notorious lithium polysulfide (LiPS) shuttle effects in lithium-sulfur (Li-S) batteries for years, but more study is needed. Herein, a water dispersible and molecular interaction regulated polymer binder (PNAVS) for Li-S batteries was elaborately designed by co-polymerizing -acryloyl glycinamide and 3-(1-vinyl-3-imidazolio)propanesulfonate. We demonstrate that by modulating the multiple interactions between the functional groups through copolymerization the binder was able to coordinate the LiPSs with higher binding energy for shuttle effect alleviation and cycling performance improvement. In addition, the Li diffusion coefficient is also optimized in the PNAVS binder, which facilitates acceleration of the redox kinetics during cycling. Consequently, the PNAVS binder renders the Li-S battery with an ultrastable open circuit voltage for more than 3000 h. Even with a high sulfur loading of 11.7 mg cm, the battery can still exhibit excellent areal capacity of 12.21 mA h cm. As proof of concept, a pouch cell was also demonstrated with the stable cycling performance for 110 cycles. The binder engineering strategy in this work will propel the practical applications of high-performance batteries.
多年来，聚合物粘结剂已被证明能有效克服锂硫（Li-S）电池中臭名昭著的多硫化锂（LiPS）穿梭效应，但仍需更多研究。在此，通过将丙烯酰甘氨酰胺和3-(1-乙烯基-3-咪唑啉)丙烷磺酸盐共聚，精心设计了一种用于Li-S电池的水分散性且分子相互作用可控的聚合物粘结剂（PNAVS）。我们证明，通过共聚调节官能团之间的多重相互作用，该粘结剂能够以更高的结合能配位LiPS，从而减轻穿梭效应并改善循环性能。此外，PNAVS粘结剂中的锂扩散系数也得到优化，这有助于加速循环过程中的氧化还原动力学。因此，PNAVS粘结剂使Li-S电池具有超过3000小时的超稳定开路电压。即使硫负载量高达11.7 mg cm，该电池仍能表现出12.21 mA h cm的优异面积容量。作为概念验证，还展示了一个软包电池，其具有110次循环的稳定循环性能。这项工作中的粘结剂工程策略将推动高性能电池的实际应用。
