题目：Electrospun Nanostructured Composite Fiber Anodes for Li-ion Batteries报告人：Limin Zhou Department of Mechanical Engineering, The Hong Kong Polytechnic University
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.