Zhou Hang-Yu, Sui Zhu-Yin, Zhao Fu-Lai, Sun Ya-Nan, Wang Hai-Yan, Han Bao-Hang
Key Laboratory of Applied Chemistry of Hebei Province, College of Environmental and Chemical Engineering, Yanshan University, Qinhuangdao 066004, People's Republic of China. CAS Key Laboratory of Nanosystem and Hierarchical Fabrication, CAS Center for Excellence in Nanoscience, National Center for Nanoscience and Technology, Beijing 100190, People's Republic of China.
Nanotechnology. 2020 Jul 31;31(31):315601. doi: 10.1088/1361-6528/ab8989. Epub 2020 Apr 15.
Lithium-sulfur batteries are considered as the next generation of energy storage systems because of their high theoretical specific capacity and energy density. Unfortunately, the sluggish reaction kinetics, weak adsorption toward to lithium polysulfides, and slow lithium ion diffusion impede the smooth electrochemical process, resulting in the lithium-sulfur batteries with the unsatisfactory cycling stability and rate performance. Since it is recognized that polar metal oxides and doped nitrogen in carbon materials have chemical interaction with lithium polysulfides, a nanostructured nitrogen-doped porous carbon/MoO composite is synthesized through a simple hydrothermal method by using graphene oxide nanoribbon and phosphomolybdic acid hydrate as precursors. The porous nanostructure promotes the charge and mass transport, while MoO nanoparticles immobilize lithium polysulfides via strong chemisorption and enhance the redox kinetics of polysulfides owing to the efficient catalytic activity in liquid-solid boundary. Consequently, the as-obtained nanostructured porous carbon/MoO-based sulfur cathode exhibits low polarization, high initial discharge capacity (1403 mAh g at 0.1 C), good rate capabilities (584 mAh g at 4 C), and impressive cycling performance at 1 C (503 mAh g after 500 cycles with capacity fade rate of 0.07% per cycle).
锂硫电池因其高理论比容量和能量密度而被视为下一代储能系统。不幸的是，缓慢的反应动力学、对多硫化锂的弱吸附以及锂离子的缓慢扩散阻碍了电化学过程的顺利进行，导致锂硫电池的循环稳定性和倍率性能不尽人意。由于人们认识到极性金属氧化物和碳材料中的掺杂氮与多硫化锂具有化学相互作用，因此以氧化石墨烯纳米带和磷钼酸水合物为前驱体，通过简单的水热法合成了一种纳米结构的氮掺杂多孔碳/MoO复合材料。多孔纳米结构促进了电荷和质量传输，而MoO纳米颗粒通过强化学吸附固定多硫化锂，并由于在液固界面的高效催化活性而增强了多硫化物的氧化还原动力学。因此，所制备的基于纳米结构多孔碳/MoO的硫正极表现出低极化、高初始放电容量（在0.1 C下为1403 mAh g）、良好的倍率性能（在4 C下为584 mAh g）以及在1 C下令人印象深刻的循环性能（500次循环后为503 mAh g，容量衰减率为每循环0.07%）。
