Liu Wenxin, Chu Yuhang, Zhou Jinwei, Chen Xuanfeng, Wang Yujie, Li Jinhui, Wu Feixiang
Faculty of Materials Metallurgy and Chemistry Jiangxi University of Science and Technology Ganzhou 341000 China.
School of Metallurgy and Environment Central South University Changsha 410083 China.
Small Sci. 2023 Apr 6;3(6):2300006. doi: 10.1002/smsc.202300006. eCollection 2023 Jun.
Sulfur cathode materials in lithium-sulfur chemistry suffer from poor electronic conductivity and shuttle of lithium polysulfides during charging and discharging. Serious shuttle effects and the sluggish redox reaction kinetics of polysulfides severely limit the development of lithium-sulfur batteries with high sulfur loading, impeding the practical process of lithium-sulfur batteries. Herein, a honeycomb73x02010;structured CoF@C is introduced as a functional layer adhered to the separator, achieving rapid lithium-ion transport, high catalytic activity, and suppressed shuttle effect simultaneously. As a result, the cell with CoF-modified separator presents satisfactory cycle stability with a capacity decay of 0.076% per cycle within 300 cycles at 1 C rate with the sulfur loading of 2.0 mg cm. A low-capacity decay of 0.088% per cycle for 200 cycles at 0.2 C is also achieved with sulfur loading of 3.0 mg cm. In addition, a high-capacity retention of 697.5 mA g is achieved with sulfur loading of 4.0 mg cm and the electrolyte volume/sulfur mass (E/S) ratio of 8 μL mg.
锂硫化学中的硫正极材料存在电子导电性差以及充放电过程中多硫化锂穿梭的问题。严重的穿梭效应和多硫化物缓慢的氧化还原反应动力学严重限制了高硫负载锂硫电池的发展，阻碍了锂硫电池的实际应用进程。在此，引入一种蜂窝状结构的CoF@C作为粘附在隔膜上的功能层，同时实现了快速的锂离子传输、高催化活性和抑制穿梭效应。结果，具有CoF改性隔膜的电池表现出令人满意的循环稳定性，在1 C倍率下300次循环内容量衰减为每循环0.076%，硫负载量为2.0 mg cm 。在硫负载量为3.0 mg cm 时，在0.2 C倍率下200次循环也实现了每循环0.088%的低容量衰减。此外，在硫负载量为4.0 mg cm 且电解液体积/硫质量（E/S）比为8 μL mg 时，实现了697.5 mA g 的高容量保持率。
