Fan Zunhao, Zhu Mengting, Deng Shungui, Chen Yanhua, Zhao Yue, Qin Mengyuan, Ma Guiyuan, Wu Jinghua, Xin Xing
School of Material Science and Chemical Engineering, Ningbo University Ningbo 315211 P. R. China
Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences Ningbo 315201 P. R. China
Nanoscale Adv. 2022 Nov 22;5(2):471-478. doi: 10.1039/d2na00645f. eCollection 2023 Jan 18.
The main issue with lithium-sulfur (Li-S) batteries is the serious irreversible capacity loss caused by the polysulfide shuttle process. In this work, we propose an electro-catalytic strategy for absorbing and transferring long-chain polysulfides during the redox process, which is the key to improving the utilization of S. Reported here is a Co doped tubular g-CN (CN) modified separator (Co-TCN@PP), which successfully inhibited the polysulfide shuttle by physical absorption and catalysis, thus facilitating the high utilization of S. Co-TCN with a tube-like structure ensures the uniform dispersion of Co nanoparticles, which provides abundant active sites to absorb polysulfides. Furthermore, Co-TCN exhibits fast reaction kinetics for polysulfide conversion. A Li-S battery with Co-TCN@PP achieves superior rate capacities and a long cycle life (400 times) with capacity fading as low as 0.07% per cycle at a high Li insertion/extraction rate of 2C. Moreover, electrodes with a high sulfur loading of 5.6 mg cm can be realized by adopting the Co-TCN@PP separator.
锂硫（Li-S）电池的主要问题是多硫化物穿梭过程导致的严重不可逆容量损失。在这项工作中，我们提出了一种电催化策略，用于在氧化还原过程中吸收和转移长链多硫化物，这是提高硫利用率的关键。本文报道了一种钴掺杂的管状石墨相氮化碳（CN）修饰隔膜（Co-TCN@PP），它通过物理吸附和催化成功抑制了多硫化物穿梭，从而促进了硫的高利用率。具有管状结构的Co-TCN确保了钴纳米颗粒的均匀分散，为吸收多硫化物提供了丰富的活性位点。此外，Co-TCN对多硫化物转化表现出快速的反应动力学。采用Co-TCN@PP的锂硫电池在2C的高锂插入/脱出速率下实现了优异的倍率性能和长循环寿命（400次），容量衰减低至每循环0.07%。此外，采用Co-TCN@PP隔膜可以实现硫负载量高达5.6 mg cm的电极。
