Wang Zhouhao, Hu Junping, Liu Jing, Lim Yew Von, Song Haobin, Wang Ye, He Tingting, Huang Chunlai, Yan Xinwen, Zhang Daohong, Huang Shaozhuan
Key Laboratory of Catalysis and Energy Materials Chemistry of Ministry of Education & Hubei Key Laboratory of Catalysis and Materials Science, South-Central University for Nationalities, Wuhan, 430074, China.
Key Laboratory of Optoelectronic Materials and New Energy Technology & Nanchang Key Laboratory of Photoelectric Conversion and Energy Storage Materials, Nanchang Institute of Technology, Nanchang, 330099, China.
Small. 2022 Apr;18(15):e2106716. doi: 10.1002/smll.202106716. Epub 2022 Feb 26.
Herein, a type of hypervalent iodine compound-iodosobenzene (PhIO)-is proposed to regulate the LiPSs electrochemistry and enhance the performance of Li-S battery. PhIO owns the practical advantages of low-cost, commercial availability, environmental friendliness and chemical stability. The lone pair electrons of oxygen atoms in PhIO play a critical role in forming a strong Lewis acid-base interaction with terminal Li in LiPSs. Moreover, the commercial PhIO can be easily converted to nanoparticles (≈20 nm) and uniformly loaded on a carbon nanotube (CNT) scaffold, ensuring sufficient chemisorption for LiPSs. The integrated functional PhIO@CNT interlayer affords a LiPSs-concentrated shield that not only strongly obstructs the LiPSs penetration but also significantly enhances the electrolyte wettability and Li conduction. The PhIO@CNT interlayer also serves as a "vice current collector" to accommodate various LiPSs and render smooth LiPSs transformation, which suppresses insulating Li S /Li S layer formation and facilitates Li diffusion. The Li-S battery based on PhIO@CNT interlayer (6 wt% PhIO) exhibits stable cycling over 1000 cycles (0.033% capacity decay per cycle) and excellent rate performance (686.6 mAh g at 3 C). This work demonstrates the great potential of PhIO in regulating LiPSs and provides a new avenue towards the low-cost and sustainable application of Li-S batteries.
在此，提出了一种高价碘化合物——亚碘酰苯（PhIO），用于调节多硫化锂（LiPSs）的电化学性能并提高锂硫电池的性能。PhIO具有低成本、商业可得、环境友好和化学稳定性等实际优势。PhIO中氧原子的孤对电子在与LiPSs中的末端锂形成强路易斯酸碱相互作用中起关键作用。此外，市售的PhIO可以很容易地转化为纳米颗粒（约20纳米）并均匀负载在碳纳米管（CNT）支架上，确保对LiPSs有足够的化学吸附。集成的功能性PhIO@CNT中间层提供了一个LiPSs浓缩屏蔽层，不仅能强烈阻碍LiPSs的渗透，还能显著提高电解质润湿性和锂传导性。PhIO@CNT中间层还作为“副集流体”，以容纳各种LiPSs并实现LiPSs的顺利转化，从而抑制绝缘Li₂S/Li₂Sₓ层的形成并促进锂扩散。基于PhIO@CNT中间层（6 wt% PhIO）的锂硫电池在1000次循环中表现出稳定的循环性能（每次循环容量衰减0.033%）和优异的倍率性能（在3 C下为686.6 mAh g⁻¹）。这项工作证明了PhIO在调节LiPSs方面的巨大潜力，并为锂硫电池的低成本和可持续应用提供了一条新途径。
