Insight to the synergistic effect of N-doping level and pore structure on improving the electrochemical performance of sulfur/N-doped porous carbon cathode for Li-S batteries. (April 2019)

• Record Type: Journal Article
• Authors: Wang, Shanxing; Zou, Kaixiang; Qian, Yunxian; Deng, Yuanfu; Zhang, Lei; Chen, Guohua
• Is Part Of: Carbon. Volume 144(2019)
• Page Start: 745
• Page End: 755
• Publication Date: 2019-04
• Subjects: Li-S batteries -- N-doped carbon -- Pore structure -- Synergistic effect -- Electrochemical performance; Carbon -- Periodicals; Carbone -- Périodiques; Koolstof; Toepassingen; Electronic journals; 546.681
• DOI: 10.1016/j.carbon.2018.12.113
• Languages: English
• ISSNs: 0008-6223

Abstract

Abstract: Three nitrogen-doped porous carbons (NDPCs) with the ultrahigh specific surface areas are prepared via a one-step activation of the biomass waste. The as-prepared samples have different levels of nitrogen contents and pore structure. These sulfur hosting matrix materials are designed to systematically elaborate the effect of N-doping level and pore structure on the electrochemical performance of the S/NDPC nanocomposites. The higher volume ratio of marco-mesopores to micropores of the substrate can greatly enhance the rate capability of the S/NDPC cathodes. This is attributed to the improved electrolyte penetration via the rich marco-mesopores. Meanwhile, the higher nitrogen content of the NDPC contributes to improving the cycle stability of the S/NDPC cathode, which is assigned to the strong chemical adsorption and physical restriction of polysulfides by the interaction of nitrogen atom and polysulfides. Therefore, the S/NDPC-1 cathode, prepared by using a NDPC matrix with high nitrogen content, large specific surface area, and a moderate microporous volume percentage (VMicro /VT ), displays an obvious enhancement in the electrochemical performance. It exhibits specific capacities of 926.1 and 815.8 mAh g −1 at 0.5 and 1.0 C rate, respectively, with a capacity fading rate of only 0.067% per cycle after 500 cycles at 1.0 C. Graphical abstract: Image 1