Self-branched Nb2O5 nanoarrays as “electron-ion reservoirs” to enhance the conversion of polysulfides in flexible Li–S batteries,Inorganic Chemistry Frontiers

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Self-branched Nb2O5 nanoarrays as “electron-ion reservoirs” to enhance the conversion of polysulfides in flexible Li–S batteries
Inorganic Chemistry Frontiers ( IF 6.1 ) Pub Date : 2021-07-29 , DOI: 10.1039/d1qi00735a
Huanhuan Li ₁ , Huiqin Chen ₁ , Yuxin Chen ₁ , Guangyue Bai ₁ , Mengjie Zhang ₁ , Shanshan Xie ₂ , Kelei Zhuo ₁

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Li–S batteries (LSBs) are promising next-generation energy-storage devices due to their high theoretical capacity and cost effectiveness. However, the widespread use of LSBs is still impeded by the low conductivity of sulfur, the volume expansion of active materials, and the shuttle effect of lithium polysulfides (LiPSs) in practical conditions. In this work, a novel sulfur matrix integrating self-branched Nb₂O₅ nanoarrays and flexible carbon cloth (NBCC) is designed and prepared. The conformal S@NBCC composite provides surface-to-surface contact between sulfur and the catalytic mediator, thus exposing more active sites for trapping LiPSs. Meanwhile, the selected Nb₂O₅ nanoarrays with ultrafast Li⁺ motion capability can work as “electron-ion reservoirs” to further accelerate the conversion reaction of LiPSs. Moreover, the extra-free space among the branched nanoarrays can not only facilitate the infiltration of the liquid electrolyte, but also enhance its tolerance to volume expansion of sulfur during the lithiation process. Benefitting from these synergistic effects, the self-supported S@NBCC shows a high specific capacity of 1262.5 mA h g⁻¹ at 0.1 C and maintains an impressive specific capacity of 759.6 mA h g⁻¹ even after 300 cycles at 1 C, showing great potential in promoting the practical application of flexible LSBs.

中文翻译：

自支化 Nb2O5 纳米阵列作为“电子离子库”以增强柔性锂硫电池中多硫化物的转化

锂硫电池 (LSB) 因其高理论容量和成本效益而成为有前途的下一代储能设备。然而，由于硫的低电导率、活性材料的体积膨胀以及多硫化锂（LiPSs）在实际条件下的穿梭效应，LSBs的广泛应用仍然受到阻碍。在这项工作中，设计并制备了一种集成自支化 Nb ₂ O ₅纳米阵列和柔性碳布 (NBCC)的新型硫基质。共形 S@NBCC 复合材料在硫和催化介质之间提供了表面对表面的接触，从而暴露了更多的活性位点来捕获 LiPS。同时，选定的具有超快 Li ^{+ 的}Nb ₂ O ₅纳米阵列运动能力可以作为“电子离子库”进一步加速LiPSs的转化反应。此外，分支纳米阵列之间的额外自由空间不仅可以促进液体电解质的渗透，还可以增强其对锂化过程中硫体积膨胀的耐受性。受益于这些协同效应，自支撑的 S@NBCC在 0.1 C 下显示出 1262.5 mA hg ^-1的高比容量，并且即使在 1 C 下 300 次循环后仍保持令人印象深刻的 759.6 mA hg ^-1比容量，显示出巨大的潜力促进灵活 LSB 的实际应用。

更新日期：2021-08-16

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