The shuttle effect of lithium–sulfur batteries (LSBs) caused by the dissolution and migration of lithium polysulfides (LiPSs) leads to rapid capacity decay of sulfur cathodes. Modifying the separator with a catalytic layer becomes an effective strategy to inhibit LiPS shuttling and promote the conversion kinetics of sulfur active materials. Herein, we propose a carbon nanotube (CNT)-encapsulation strategy to fabricate a composite of CoSe nanoparticles encapsulated in N-doped CNT (CoSe@NCNT). The as-prepared CoSe@NCNT is endowed with a full sulfiphilic surface to trap LiPSs by Co–S and Se–Li bonds and catalyze sulfur redox reactions (SRRs) of the discharge/charge processes. In addition, the encapsulated structure effectively inhibits the aggregation of CoSe nanoparticles and enables its persistent adsorption–catalysis ability on regulating the kinetics of SRRs. When equipped with a CoSe@NCNT catalytic interlayer, the LSB shows a high specific capacity of 768.3 mAh g^–1 at 2 C and superior cycle stability with the capacity decay rate of 0.06% per cycle over 1000 cycles at 1 C. In addition, when operated with an electrolyte/sulfur ratio of 5 μL mg^–1, the modified battery with a sulfur loading of 4.0 mg cm^–2 delivers a specific capacity of 746.9 mAh g^–1 at 0.2 C. Our studies provide a CNT-encapsulation strategy to develop transition metal-based catalytic materials for high-performance LSBs.

中文翻译：

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将硒化钴纳米粒子原位封装在具有完全亲硫表面的氮掺杂碳纳米管中作为锂硫电池的催化中间层

由多硫化锂（LiPS）的溶解和迁移引起的锂硫电池（LSB）的穿梭效应导致硫正极的容量快速衰减。用催化层修饰隔膜成为抑制LiPS穿梭和促进硫活性材料转化动力学的有效策略。在此，我们提出了一种碳纳米管（CNT）封装策略来制造封装在 N 掺杂 CNT 中的 CoSe 纳米颗粒复合材料（CoSe@NCNT）。所制备的 CoSe@NCNT 具有完全亲硫表面，可通过 Co-S 和 Se-Li 键捕获 LiPS，并催化放电/充电过程的硫氧化还原反应 (SRR)。此外，封装结构有效抑制CoSe纳米颗粒的聚集，并使其具有持久的吸附催化能力来调节SRR的动力学。当配备 CoSe@NCNT 催化中间层时，LSB 在 2 C 下表现出 768.3 mAh g ^–1的高比容量，并具有出色的循环稳定性，在 1 C 下经过 1000 次循环，容量衰减率为 0.06%。此外，当电解质/硫比为 5 μL mg ^{–1时，硫负载量为 4.0 mg cm –2}的改进电池在 0.2 C 下的比容量为 746.9 mAh g ^–1。我们的研究提供了一种 CNT 封装策略开发用于高性能LSB的过渡金属基催化材料。