Guo Dong, Li Xiang, Wahyudi Wandi, Li Chunyang, Emwas Abdul-Hamid, Hedhili Mohamed Nejib, Li Yangxing, Lai Zhiping
Division of Physical Science and Engineering, King Abdullah University of Science and Technology (KAUST), Thuwal 23955-6900, Saudi Arabia.
Core Laboratories, King Abdullah University of Science and Technology (KAUST), Thuwal 23955-6900, Saudi Arabia.
ACS Nano. 2020 Dec 22;14(12):17163-17173. doi: 10.1021/acsnano.0c06944. Epub 2020 Nov 9.
A popular practice in Li-S battery research is to utilize highly nanostructured hosts and excessive electrolytes to enhance sulfur-specific capacities. However, from the perspective of commercialization, this is a less meaningful approach in the pursuit of high-energy Li-S batteries. Herein, we report the fabrication of a nanoskin composed of a conjugated microporous polymer by electropolymerization to create a closed system for a sulfur cathode. The nanoskin is ultrathin, conductive, continuous, and contains uniform micropores of approximately 0.8 nm. The nanoskin sealing prevents the shuttling of polysulfide species without using the absorption effect, enhances the utilization of electrolytes, and allows a fast transport of lithium ions. As a result, the Li-S batteries comprising the cathode with nanoskin exhibit superior stability (∼86% capacity retention) under lean electrolyte conditions and a prolonged lifetime (1000 cycles). At a low electrolyte/sulfur ratio of 4 μL mg, the designed cathode delivered a practical energy density of over 300 Wh kg without using any sophisticated hosts.
锂硫电池研究中的一种常见做法是利用高度纳米结构化的主体材料和过量的电解质来提高硫的比容量。然而，从商业化的角度来看，在追求高能量锂硫电池时，这种方法意义不大。在此，我们报告了通过电聚合制备由共轭微孔聚合物组成的纳米皮，以创建用于硫阴极的封闭系统。该纳米皮超薄、导电、连续，且包含约0.8纳米的均匀微孔。纳米皮密封可防止多硫化物穿梭，无需利用吸收效应，提高了电解质的利用率，并允许锂离子快速传输。结果，包含具有纳米皮阴极的锂硫电池在贫电解质条件下表现出卓越的稳定性（容量保持率约86%）和延长的寿命（1000次循环）。在4 μL mg的低电解质/硫比下，所设计的阴极在不使用任何复杂主体材料的情况下提供了超过300 Wh kg的实际能量密度。
