Ren Zhiheng, Li Jixiao, Gong Yangyang, Li Xianliang, Liang Jianneng, Li Yongliang, He Chuanxin, Zhang Qianling, Ren Xiangzhong
College of Chemistry and Environmental Engineering, International Joint Research Center for Molecular Science, Shenzhen University, Shenzhen, Guangdong 518060, PR. China; Key Laboratory of Optoelectronic Devices and Systems of Ministry of Education and Guangdong Province, College of Physics and Optoelectronic Engineering, Shenzhen University, Shenzhen 518060, PR. China.
College of Chemistry and Environmental Engineering, International Joint Research Center for Molecular Science, Shenzhen University, Shenzhen, Guangdong 518060, PR. China.
J Colloid Interface Sci. 2022 Mar;609:43-53. doi: 10.1016/j.jcis.2021.12.003. Epub 2021 Dec 2.
The practical application of Lithium-sulfur (Li-S) batteries is significantly inhibited by (i) the notable 'shuttle effect' of lithium polysulfides (LiPS), (ii) the corrosion of the lithium interface, and (iii) the sluggish redox reaction kinetics. The functional separator in the Li-S battery has the potential to provide the perfect solution to these problems. Herein a triple-layer multifunctional PVDF-based nanofiber separator, which contains GoTiN/PVDF layer on the top and bottom and ZnTPP/PVDF layer on the middle, is designed. The polarity and porous structure of this multifunctional separator can greatly improve the wettability of electrolytes and enhance the transportation of Li. With the zinc-based porphyrin framework (ZnTPP) structure, this separator has a strong chemisorption and LiPS conversion ability, which greatly prevent the 'shuttle effect'. Consequently, the designed multilayer separator showed excellent electrochemical performance. As a result, the cell with GoTiN@ZnTPP@GoTiN nanofiber membrane displayed an initial discharge capacity of 1180 mAh/g with a benign capacity retention of 65.9% at 0.5C and high coulombic efficiency of more than 98.5% after 100 cycles. Even at 2C, it can still release a capacity of 798 mAh/g. Moreover, the remarkable capacity of 591 mAh/g could be achieved with a high sulfur load of 5.76 mg/cm under a current density of 0.1C. Based on these merits, this novel and scalable multifunctional separator is a promising candidate to replace the conventional PP separator for advanced Li-S batteries to deal with various challenges.
锂硫（Li-S）电池的实际应用受到以下因素的显著制约：（i）多硫化锂（LiPS）明显的“穿梭效应”；（ii）锂界面的腐蚀；（iii）缓慢的氧化还原反应动力学。Li-S电池中的功能隔膜有潜力为这些问题提供完美解决方案。在此，设计了一种基于聚偏氟乙烯（PVDF）的三层多功能纳米纤维隔膜，其顶部和底部为GoTiN/PVDF层，中间为ZnTPP/PVDF层。这种多功能隔膜的极性和多孔结构可极大提高电解质的润湿性并增强锂的传输。基于锌基卟啉骨架（ZnTPP）结构，该隔膜具有很强的化学吸附和LiPS转化能力，可极大防止“穿梭效应”。因此，所设计的多层隔膜表现出优异的电化学性能。结果，具有GoTiN@ZnTPP@GoTiN纳米纤维膜的电池在0.5C下初始放电容量为1180 mAh/g，100次循环后容量保持率良好，为65.9%，库仑效率高于98.5%。即使在2C时，它仍可释放798 mAh/g的容量。此外，在0.1C电流密度下，硫负载为5.76 mg/cm²时可实现591 mAh/g的显著容量。基于这些优点，这种新型且可扩展的多功能隔膜有望替代传统的聚丙烯（PP）隔膜，用于先进的Li-S电池以应对各种挑战。
