CAS Key Laboratory of Nanosystem and Hierarchical Fabrication, CAS Center for Excellence in Nanoscience, National Centre for Nanoscience and Technology, Beijing, 100190, P. R. China.
University of Chinese Academy of Sciences, 19 A Yuquan Rd, Shijingshan District, Beijing, 100049, P. R. China.
Adv Mater. 2017 Jun;29(21). doi: 10.1002/adma.201606817. Epub 2017 Mar 20.
A high lithium conductive MoS /Celgard composite separator is reported as efficient polysulfides barrier in Li-S batteries. Significantly, thanks to the high density of lithium ions on MoS surface, this composite separator shows high lithium conductivity, fast lithium diffusion, and facile lithium transference. When used in Li-S batteries, the separator is proven to be highly efficient for depressing polysulfides shuttle, leading to high and long cycle stability. With 65% of sulfur loading, the device with MoS /Celgard separator delivers an initial capacity of 808 mAh g and a substantial capacity of 401 mAh g after 600 cycles, corresponding to only 0.083% of capacity decay per cycle that is comparable to the best reported result so far. In addition, the Coulombic efficiency remains more than 99.5% during all 600 cycles, disclosing an efficient ionic sieve preventing polysulfides migration to the anode while having negligible influence on Li ions transfer across the separator. The strategy demonstrated in this work will open the door toward developing efficient separators with flexible 2D materials beyond graphene for energy-storage devices.
一种高锂离子传导性 MoS/Celgard 复合隔膜被报道为 Li-S 电池中有效的多硫化物阻隔物。值得注意的是，由于 MoS 表面上锂离子的高密度，这种复合隔膜表现出高锂离子传导性、快速锂离子扩散和易于锂离子转移。当用于 Li-S 电池时，该隔膜被证明对抑制多硫化物穿梭具有高效性，从而实现了高且长的循环稳定性。在 65%的硫载量下，带有 MoS/Celgard 隔膜的器件在 600 次循环后提供了 808 mAh g 的初始容量和 401 mAh g 的实质性容量，这相当于每个循环仅 0.083%的容量衰减，与迄今为止报道的最佳结果相当。此外，在所有 600 次循环中，库仑效率保持在 99.5%以上，表明该隔膜是一种有效的离子筛，可防止多硫化物向阳极迁移，同时对锂离子在隔膜中的迁移几乎没有影响。本工作中展示的策略将为开发用于储能器件的高效、具有柔性二维材料的隔膜开辟道路，超越了石墨烯。
