周利民教授主要研究包括:先进工程材料与结构的制造,表征和力学特征,包括纤维增强高分子基复合材料,智能材料与结构,纳米材料及技术,基于納米材料与结构的锂电池材料,及基于超声导波的结构健康监测技术。他在以上领域发表文章300余篇,包括200 余篇SCI国际期刊论文,并撰写了所从事研究领域的参考书籍的部分章节。周利民教授目前是中国复合材料学会副理事长,香港研究资助局工程学学科专家组成员。
内容摘要:Considerable attention has been paid to rechargeable lithium ion batteries (LIBs) because of their high energy density and long cycle lifetime. However, exploring and developing novel electrode materials with sufficiently high energy and power density to meet the requirements imposed on application of LIBs in high-power devices such as electric vehicles (EV) and hybrid electric vehicles (HEV) remains a challenge. In this study, we have successfully prepared amorphous carbon nanofibers and carbon nanotubes decorated with hollow graphitic carbon nanospheres by electrospinning method. A hollow-tunnel structure in electrospun carbon/Ni nanofibres was also produced by diffusing Ni nanoparticles from the graphitic carbon spheres into amorphous carbon nanofibres, which turns amorphous carbon into graphitic carbon. The resultant materials were further treated by chemical activation and acid treatment to develop activated N-doped hollow-tunneled graphitic carbon nanofibers (ANHTGCNs). In a typical application, we demonstrated that the prepared ANHTGCNs are excellent anode materials for LIBs, displaying a super high reversible specific capacity of over ~1560 mAh g-1 and a remarkable volumetric capacity of ~1.8 Ah cm-3 at a current density of 0.1 A g-1 with outstanding rate capability and good cycling stability. The other material is a novel porous TiO2-carbon (TiO2-C) composite nanofibers in which Sn nanoparticles is encapsulated. In situ TEM was used to study the structural changes and charging/discharging processes of TiO2-C-Sn composite nanofibers. It was found that the porous TiO2-C can accommodate volumetric change of Sn nanoparticles. As an anode, this material shows a high capacity (875 mAh/g after 50 cycles when the current density is 0.1 A/g), long cycle life (over 10000 cycles at rate of 3 A/g with maintained capacity of 160 mAh/g), and good rate capability.