The shuttle effect of polysulfides poses a significant obstacle to the commercialization of lithium-sulfur (Li–S) batteries. Covalent organic frameworks have been widely used in Li–S batteries as porous crystalline materials to suppress the shuttle effect. Herein, a 3,5-bis(trifluoromethyl)benzyl (BTFMB-TzDa) modified triazine-based covalent organic framework was synthesized. The high electronegativity and large steric hindrance of the BTFMB-TzDa modified separator successfully suppressed the diffusion of polysulfides, leading to improved capacity and cyclic stability of Li–S batteries. Cells with the BTFMB-TzDa modified separator exhibited a high initial capacity of 1205 mA h g⁻¹ at 0.2C and 657 mA h g⁻¹ at 3.0C. Furthermore, the capacity still remained at 501 mA h g⁻¹ after 500 cycles. The BTFMB-TzDa modified separator provides an alternative strategy for the construction of high-performance Li–S batteries.

中文翻译：

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3,5-双(三氟甲基)苄基改性三嗪基共价有机框架抑制锂硫电池中多硫化物的穿梭效应

多硫化物的穿梭效应对锂硫（Li-S）电池的商业化构成了重大障碍。共价有机骨架作为多孔晶体材料已广泛用于Li-S电池中以抑制穿梭效应。在此，合成了3,5-双(三氟甲基)苄基(BTFMB-TzDa)修饰的三嗪基共价有机骨架。BTFMB-TzDa改性隔膜的高电负性和大空间位阻成功抑制了多硫化物的扩散，从而提高了Li-S电池的容量和循环稳定性。^{具有BTFMB-TzDa改性隔膜的电池在0.2C下表现出1205 mA hg -1}的高初始容量，在3.0C下表现出657 mA hg ^-1的高初始容量。此外，500次循环后容量仍保持在501mA hg ^-1。BTFMB-TzDa 改良隔膜为构建高性能锂硫电池提供了另一种策略。