Wang Jie, Wu Ling, Shen Lina, Zhou Qun, Chen Yuling, Wu Juan, Wen Yali, Zheng Junwei
College of Chemistry, Chemical Engineering and Materials Science, Soochow University, Suzhou 215123, China.
School of Iron and Steel, Soochow University, Suzhou 215137, China.
J Colloid Interface Sci. 2023 Jun 15;640:415-422. doi: 10.1016/j.jcis.2023.02.123. Epub 2023 Feb 28.
A new strategy is developed to fabricate sulfur electrode by infusing sulfur into a conductive biochar decorated with highly dispersed CoO nanoparticles. The loading of the CoO nanoparticles, as the active sites for reactions, is efficiently increased by using the microwave-assisted diffusion method. It is demonstrated that biochar can serve as an excellent conductive framework to effectively activate sulfur. Simultaneously, the CoO nanoparticles possessing excellent capability to adsorb polysulfides can remarkably alleviate the dissolution of polysulfides, and greatly enhance the conversion kinetics between the polysulfides and LiS/LiS in the charge/discharge processes. The sulfur electrode dual-functionalized with biochar and CoO nanoparticles exhibits excellent electrochemical performance, including high initial discharge specific capacity of 930.5 mAh g and low capacity decay rate of 0.069 % per cycle during 800 cycles at 1C rate. It is particularly interesting that the CoO nanoparticles distinctively enhance the Li diffusion during the charge process, endowing the material with excellent high-rate charging performance. This could be beneficial for the development of Li-S batteries with fast charging feature.
通过将硫注入到装饰有高度分散的CoO纳米颗粒的导电生物炭中来制备硫电极，从而开发出一种新策略。通过使用微波辅助扩散法，作为反应活性位点的CoO纳米颗粒的负载量得到有效提高。结果表明，生物炭可作为优异的导电骨架来有效活化硫。同时，具有优异多硫化物吸附能力的CoO纳米颗粒可显著减轻多硫化物的溶解，并在充放电过程中极大地提高多硫化物与Li₂S/Li₂S₂之间的转化动力学。用生物炭和CoO纳米颗粒双功能化的硫电极表现出优异的电化学性能，包括在1C倍率下800次循环期间的高初始放电比容量930.5 mAh g⁻¹和低容量衰减率0.069%/循环。特别有趣的是，CoO纳米颗粒在充电过程中显著增强了Li⁺扩散，赋予材料优异的高倍率充电性能。这对于开发具有快速充电特性的锂硫电池可能是有益的。
