Abstract

The commercial application of lithium-sulfur (Li-S) battery is hampered by the insulating characteristic and dissolution problem of sulfur and lithium polysulfides. Herein, a mesoporous TiO₂@PPy material has been fabricated to act as the chemical immobilizer for sulfur species in Li-S battery. In the structure, PPy layer is covered uniformly on surface of the mesoprous TiO₂, forming a core-shell structure. The well-developed mesopores act as the reservoir for sulfur, while the PPy layer improves the conductivity of material and further prevents diffusion of soluble polysulfides. The synthesized TiO₂/S@PPy composite delivers an improved rate capability and cycling stability, with an initial discharge specific capacity of 1013.7 mAh g⁻¹ at 0.1 C. In addition, the composite reserves a high capacity of 567.0 mAh g⁻¹ after 300 cycles at 0.5 C, with a decreasing rate of 0.103% per cycle.

中文翻译：

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高性能Li-S电池中多硫化物化学吸附的TiO 2 / S @ PPy复合材料的合成

摘要

锂硫（Li-S）电池的商业应用受到硫和多硫化锂的绝缘特性和溶解问题的困扰。在此，已经制备了介孔TiO ₂ @PPy材料以用作Li-S电池中硫物种的化学固定剂。在该结构中，PPy层均匀地覆盖在中链TiO _2的表面上，形成核-壳结构。发达的中孔充当硫的储层，而PPy层则提高了材料的电导率并进一步防止了可溶性多硫化物的扩散。合成的TiO ₂ / S @ PPy复合材料具有更高的倍率性能和循环稳定性，初始放电比容量为1013.7 mAh g ^-1此外，该复合材料在0.5 C下300次循环后，仍具有567.0 mAh g ^-1的高容量，每个循环的下降率为0.103％。