基于ZnCo2O4的多孔碳纳米纤维制备及其储能性能

针对锂硫电池循环过程中容量衰减快的问题,采用水热法制备ZnCo₂O₄纳米颗粒,然后与聚丙烯腈(PAN)混合,通过静电纺丝法制备复合纳米纤维并进行炭化处理得到复合多孔碳纳米纤维。借助扫描电子显微镜、透射电子显微镜、X射线光电子能谱仪、拉曼光谱仪、比表面积测试仪表征复合多孔碳纳米纤维的微观结构和物化性能,优化得到最佳制备工艺;并将其作为正极硫载体测试电化学性能。结果表明:基于ZnCo₂O₄制备的复合多孔碳纳米纤维存在大量孔孔相连的通道,比表面积高达210.85 m²/g;组装成的锂硫电池具有典型的充放电平台以及明显的氧化还原峰,其初始放电比容量为759.2 mA·h/g,50圈充放电循环后,仍具有74.0%的可逆比容量,相比于不掺杂ZnCo₂O₄的静电纺丝碳纳米纤维具有更高的比容量,更好的倍率性能。

Preparation and energy storage of porous carbon nanofibers based on ZnCo2O4

Aiming at the problem of rapid capacity decay during the cycling of lithium-sulfur batteries, ZnCo₂O₄ nanoparticles were prepared by a hydrothermal method, and the nanoparticles were mixed with polyacrylonitrile to prepare composite nanofibers by electrostatic spinning followed by carbonization. Scanning electron microscope, transmission electron microscope, X-ray photoelectron spectroscopy, raman spectroscopy, and specific surface area measurements were used to characterize the microstructure and physical and chemical properties of the composite porous carbon nanofibers. The optimal preparation process was identified, and the porous carbon nanofibers were used as the positive sulfur carrier to test its electrochemical performance. The results show that the composite porous carbon nanofibers prepared based on ZnCo₂O₄ has a large number of channels connected by pores, and the specific surface area is as high as 210.85 m²/g. The assembled lithium-sulfur battery has a typical charge-discharge platform and a significant oxygen reduction peak. An initial discharge specific capacity of 759.2 mA·h/g is achieved, and it still has a reversible specific capacity of 74.0% after 50 charge-discharge cycles. Compared with electrospinning carbon nanofibers without ZnCo₂O₄ doping, the porous carbon nanofibres has better specific capacity and higher rate performance.