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Efficient Polysulfide Trapping and Conversion on N-Doped CoTe2 via Enhanced Dual-Anchoring Effect
Small ( IF 13.0 ) Pub Date : 2021-09-14 , DOI: 10.1002/smll.202102962
Xueqin Song 1 , Da Tian 1 , Yue Qiu 1 , Xun Sun 1 , Bo Jiang 1 , Chenghao Zhao 1 , Yu Zhang 1 , Xianzhu Xu 1 , Lishuang Fan 2 , Naiqing Zhang 3
Affiliation  

Polysulfide shuttling and sluggish sulfur redox kinetics hinder the cyclability and rate capability of lithium–sulfur (Li–S) batteries. The intrinsic redox kinetics of sulfur cathodes strongly depends on the interaction between catalysts and sulfur species. Herein, N-doped CoTe2 is proposed as an effective dual-anchoring electrocatalyst, which can simultaneously bind Li and S atoms in lithium polysulfides via ionic Te–Li/N–Li bonding and coordinate covalent Co–S bonding. The incorporated N not only serves as enhanced lithiophilic site, but also an agent to improve the sulfiphilicity of the Co site as revealed by a series of experimental and computational results. Benefiting from these superiorities, the use of N-doped CoTe2 as a catalytic interlayer enables efficient operation of Li–S batteries in terms of impressive rate capability of 758 mAh g−1 at 4 C and very low capacity decay of 0.021% per cycle over 1000 cycles. The material and strategy demonstrated in this work may open the door toward developing more advanced Li–S electrocatalysts.

中文翻译:

通过增强的双锚定效应对 N 掺杂 CoTe2 进行有效的多硫化物捕获和转化

多硫化物穿梭和缓慢的硫氧化还原动力学阻碍了锂硫(Li-S)电池的循环性能和倍率性能。硫正极的固有氧化还原动力学强烈依赖于催化剂和硫物质之间的相互作用。在此,N 掺杂的 CoTe 2被认为是一种有效的双锚定电催化剂,它可以通过离子 Te-Li/N-Li 键和配位共价 Co-S 键同时结合多硫化锂中的 Li 和 S 原子。一系列实验和计算结果表明,掺入的 N 不仅可以作为增强的亲锂位点,而且还可以提高 Co 位点的亲硫性。受益于这些优势,使用 N 掺杂的 CoTe 2作为催化夹层,Li-S 电池能够在 4 C 下达到 758 mAh g -1的令人印象深刻的倍率性能和 1000 次循环中每循环 0.021% 的非常低的容量衰减,从而使锂硫电池能够有效运行。这项工作中展示的材料和策略可能为开发更先进的 Li-S 电催化剂打开大门。
更新日期:2021-10-21
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