Xiang Meng, Li Jiajin, Feng Shuaiqiang, Zhang Haiyang, Cao Xueli, Zeng Yaping, Li Xinyu, Xiao Jianrong
College of Science, Guilin University of Technology, Guilin 541004, PR China.
College of Science, Guilin University of Technology, Guilin 541004, PR China.
J Colloid Interface Sci. 2022 Oct 15;624:471-481. doi: 10.1016/j.jcis.2022.05.118. Epub 2022 May 21.
The application of lithium-sulfur batteries are seriously hindered by their poor cycle stability and low sulfur utilization due to their inevitable polysulfide shuttle effect and slow reaction kinetics. Here, MoC nanorods that were surface-decorated with metallic-organic framework-derived nitrogen-doped carbon and ultrasmall cobalt nanoparticles (NC-Co@MoC) were used as the materials for lithium-sulfur battery cathodes. The prepared NC-Co@MoC@S composites had the specific capacity of 1073 mAh·g (0.2 C) and the retained 806 mAh·g after 200 cycles, thus showing excellent discharge specific capacity and cycling stability. The MoC nanorods can adsorb lithium polysulfides (LiPSs) through the formation of MoS bonds. Cobalt nanoparticles electrocatalytically accelerated the redox kinetic conversion of LiPSs. Nitrogen doping can effectively reduce the energy potential barrier. The interconnected multidimensional backbone of NC-Co@MoC composites contributed to electrolyte permeation, fast electron/Li transport, and sufficient volume change buffering. Therefore, the synergistic effect of the adsorption ability of MoC nanorods and the catalytic ability of cobalt nanoparticles can effectively improve the sulfur fixation ability of the composites and greatly suppress the shuttle effect.
锂硫电池的应用受到严重阻碍，因为其不可避免的多硫化物穿梭效应和缓慢的反应动力学导致循环稳定性差和硫利用率低。在此，用金属有机框架衍生的氮掺杂碳和超小钴纳米颗粒（NC-Co@MoC）进行表面修饰的碳化钼纳米棒被用作锂硫电池阴极材料。制备的NC-Co@MoC@S复合材料在0.2 C时的比容量为1073 mAh·g，200次循环后保留806 mAh·g，因此显示出优异的放电比容量和循环稳定性。碳化钼纳米棒可以通过形成MoS键吸附多硫化锂（LiPSs）。钴纳米颗粒电催化加速了LiPSs的氧化还原动力学转化。氮掺杂可以有效降低能垒。NC-Co@MoC复合材料相互连接的多维骨架有助于电解质渗透、快速电子/Li传输和充分的体积变化缓冲。因此，碳化钼纳米棒的吸附能力和钴纳米颗粒的催化能力的协同效应可以有效提高复合材料的固硫能力，并极大地抑制穿梭效应。
