Hong Xu-Jia, Song Chun-Lei, Yang Yan, Tan Hao-Chong, Li Guo-Hui, Cai Yue-Peng, Wang Hongxia
School of Chemistry and Environment, Guangzhou Key Laboratory of Materials for Energy Conversion and Storage, Guangdong Provincial Engineering Technology Research Center for Materials for Energy Conversion and Storage , South China Normal University , Guangzhou 510006 , P. R. China.
School of Chemistry, Physics and Mechanical Engineering , Queensland University of Technology (QUT) , Brisbane , Queensland 4001 , Australia.
ACS Nano. 2019 Feb 26;13(2):1923-1931. doi: 10.1021/acsnano.8b08155. Epub 2019 Feb 18.
In this work, we demonstrate cerium (Ce) based metal-organic frameworks (MOFs) combined with carbon nanotubes (CNTs) to form Ce-MOF/CNT composites as separator coating material in the Li-S battery system, which showed excellent electrochemical performance even under high sulfur loading and much better capacity retention. At the sulfur loading of 2.5 mg/cm, initial specific capacity of 1021.8 mAh/g at 1C was achieved in the Li-S cell with the Ce-MOF-2/CNT coated separator, which was slowly reduced to 838.8 mAh/g after 800 cycles with a decay rate of only 0.022% and the Coulombic efficiency of nearly 100%. Even at a higher sulfur loading of 6 mg/cm, the cell based on Ce-MOF-2/CNT separator coating still exhibited excellent performance with initial specific capacity of 993.5 mAh/g at 0.1 C. After 200 cycles, the specific capacity of 886.4 mAh/g was still retained. The excellent performance is ascribed to the efficient adsorption of the Ce-MOF-2 to LiS species and its catalytic effect toward conversion of polysulfides, resulting in suppressed shuttle effect of polysulfides in the Li-S batteries.
在这项工作中，我们展示了铈（Ce）基金属有机框架（MOF）与碳纳米管（CNT）相结合，形成Ce-MOF/CNT复合材料作为锂硫电池系统中的隔膜涂层材料，该材料即使在高硫负载下也表现出优异的电化学性能以及更好的容量保持率。在硫负载为2.5 mg/cm²时，采用Ce-MOF-2/CNT涂层隔膜的锂硫电池在1C下实现了1021.8 mAh/g的初始比容量，在800次循环后缓慢降至838.8 mAh/g，衰减率仅为0.022%，库仑效率接近100%。即使在更高的硫负载6 mg/cm²下，基于Ce-MOF-2/CNT隔膜涂层的电池在0.1C下仍表现出优异的性能，初始比容量为993.5 mAh/g。200次循环后，仍保留了886.4 mAh/g的比容量。优异的性能归因于Ce-MOF-2对LiS物种的有效吸附及其对多硫化物转化的催化作用，从而抑制了锂硫电池中多硫化物的穿梭效应。
