Cao Guiqiang, Bi Da, Zhao Jingxiang, Zheng Jing, Wang Zhikang, Lai Qingxue, Liang Yanyu
College of Materials Science and Technology, Nanjing University of Aeronautics and Astronautics Nanjing 210016 P. R. China
College of Chemistry and Chemical Engineering, Key Laboratory of Photonic and Electronic Bandgap Materials, Ministry of Education, Harbin Normal University Harbin 150025 China.
RSC Adv. 2020 May 5;10(29):17345-17352. doi: 10.1039/c9ra10063f. eCollection 2020 Apr 29.
Li-S batteries have been attracting increasing interest owing to their remarkable advantages of low cost, high theoretical capacity and high theoretical energy density. Nevertheless, the severe "shuttle effects" of lithium polysulfides have markedly limited the performance of the cells and further hindered their commercial applications. Herein, a novel scheme combining a transformation strategy with ammonia treatment was developed to fabricate ZIF-8-derived nitrogen-doped hierarchically porous carbon (NHPC/NH). When NHPC/NH was used as a host of sulfur, the obtained S@NHPC/NH cathode for Li-S cells presented an initial specific capacity of 1654 mA h g and an outstanding cycling stability with only 0.27% attenuation per cycle from the 30th cycle to 130th cycle. Together with the theoretical calculation, it was concluded that such excellent electrochemical performances should be attributed to the suppressed "shuttle effect" both physical and chemical adsorption of lithium polysulfides in the optimized microporous structures with effective nitrogen doping sites as well as the improved kinetics owing to the abundant meso/macroporous structures.
锂硫电池因其低成本、高理论容量和高理论能量密度等显著优势而受到越来越多的关注。然而，多硫化锂严重的“穿梭效应”显著限制了电池的性能，并进一步阻碍了它们的商业应用。在此，开发了一种将转化策略与氨处理相结合的新方案，以制备ZIF-8衍生的氮掺杂分级多孔碳（NHPC/NH）。当NHPC/NH用作硫的主体时，所制备的用于锂硫电池的S@NHPC/NH正极的初始比容量为1654 mA h g，并且具有出色的循环稳定性，从第30个循环到第130个循环，每循环仅衰减0.27%。结合理论计算得出，如此优异的电化学性能应归因于在具有有效氮掺杂位点的优化微孔结构中对多硫化锂的物理和化学吸附抑制了“穿梭效应”，以及由于丰富的介孔/大孔结构而改善的动力学。
