Liu Qing, Han Xiaotong, Park Hyunyoung, Kim Jongsoon, Xiong Peixun, Yuan Haocheng, Yeon Jeong Seok, Kang Yingbo, Park Jae Min, Dou Qingyun, Kim Bo-Kyong, Park Ho Seok
School of Chemical Engineering, Department of Health Sciences and Technology, Samsung Advanced Institute for Health Sciences and Technology (SAIHST), and SKKU Advanced Institute of Nano Technology (SAINT), Sungkyunkwan University, Suwon 440-746, Republic of Korea.
Smart Electrical & Signaling Division, Korea Railroad Research Institute (KRRI), Uiwang-si 16105, Republic of Korea.
ACS Appl Mater Interfaces. 2021 Apr 21;13(15):17978-17987. doi: 10.1021/acsami.1c00974. Epub 2021 Apr 6.
Functional separators, which are chemically modified and coated with nanostructured materials, are considered an effective and economical approach to suppressing the shuttle effect of lithium polysulfide (LiPS) and promoting the conversion kinetics of sulfur cathodes. Herein, we report cobalt-aluminum-layered double hydroxide quantum dots (LDH-QDs) deposited with nitrogen-doped graphene (NG) as a bifunctional separator for lithium-sulfur batteries (LSBs). The mesoporous LDH-QDs/NG hybrids possess abundant active sites of Co and hydroxide groups, which result in capturing LiPSs through strong chemical interactions and accelerating the redox kinetics of the conversion reaction, as confirmed through X-ray photoelectron spectroscopy, adsorption tests, LiS nucleation tests, and electrokinetic analyses of the LiPS conversion. The resulting LDH-QDs/NG hybrid-coated polypropylene (LDH-QDs/NG/PP) separator, with an average thickness of ∼17 μm, has a high ionic conductivity of 2.67 mS cm. Consequently, the LSB cells with the LDH-QDs/NG/PP separator can deliver a high discharge capacity of 1227.48 mAh g at 0.1C along with a low capacity decay rate of 0.041% per cycle over 1200 cycles at 1.0C.
经过化学改性并涂覆有纳米结构材料的功能隔膜，被认为是抑制多硫化锂（LiPS）穿梭效应和促进硫阴极转化动力学的一种有效且经济的方法。在此，我们报道了一种以氮掺杂石墨烯（NG）沉积的钴铝层状双氢氧化物量子点（LDH-QDs）作为锂硫电池（LSB）的双功能隔膜。介孔LDH-QDs/NG杂化物具有丰富的钴活性位点和羟基，通过X射线光电子能谱、吸附测试、LiS成核测试以及LiPS转化的动电分析证实，这些位点通过强烈的化学相互作用捕获LiPS并加速转化反应的氧化还原动力学。所得的平均厚度约为17μm的LDH-QDs/NG杂化物涂覆聚丙烯（LDH-QDs/NG/PP）隔膜具有2.67 mS cm的高离子电导率。因此，采用LDH-QDs/NG/PP隔膜的LSB电池在0.1C下可提供1227.48 mAh g的高放电容量，并且在1.0C下1200次循环中每循环的低容量衰减率为0.041%。
