LiV 3 O 8 /Polytriphenylamine Composites with Enhanced Electrochemical Performances as Cathode Materials for Rechargeable Lithium Batteries

摘要

LiV 3 O 8 /polytriphenylamine composites are synthesized by a chemical oxidative polymerization process and applied as cathode materials for rechargeable lithium batteries (RLB). The structure, morphology, and electrochemical performances of the composites are characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscopy, galvanostatic discharge/charge tests, and electrochemical impedance spectroscopy. It was found that the polytriphenylamine particles were composited with LiV 3 O 8 nanorods which acted as a protective barrier against the side reaction of LiV 3 O 8 , as well as a conductive network to reduce the reaction resistance among the LiV 3 O 8 particles. Among the LiV 3 O 8 /polytriphenylamine composites, the 17 wt % LVO/PTPAn composite showed the largest d 100 spacing. The electrochemical results showed that the 17 wt % LVO/PTPAn composite maintained a discharge capacity of 271 mAh·g ?1 at a current density of 60 mA·g ?1 , as well as maintaining 236 mAh·g ?1 at 240 mA·g ?1 after 50 cycles, while the bare LiV 3 O 8 sample retained only 169 and 148 mAh·g ?1 , respectively. Electrochemical impedance spectra (EIS) results implied that the 17 wt % LVO/PTPAn composite demonstrated a decreased charge transfer resistance and increased Li + ion diffusion ability, therefore manifesting better rate capability and cycling performance compared to the bare LiV 3 O 8 sample.