LiV₃O₈/Polytriphenylamine Composites with Enhanced Electrochemical Performances as Cathode Materials for Rechargeable Lithium Batteries.

LiV3O8/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 LiV3O8 nanorods which acted as a protective barrier against the side reaction of LiV3O8, as well as a conductive network to reduce the reaction resistance among the LiV3O8 particles. Among the LiV3O8/polytriphenylamine composites, the 17 wt % LVO/PTPAn composite showed the largest d100 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 LiV3O8 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 LiV3O8 sample.

通过化学氧化聚合工艺合成了LiV₃O₈/聚三苯胺复合材料，并将其用作可充电锂电池（RLB）的正极材料。利用X射线衍射、扫描电子显微镜、透射电子显微镜、恒电流放电/充电测试以及电化学阻抗谱对复合材料的结构、形貌和电化学性能进行了表征。研究发现，聚三苯胺颗粒与LiV₃O₈纳米棒复合，该纳米棒作为防止LiV₃O₈副反应的保护屏障，以及作为导电网络降低LiV₃O₈颗粒之间的反应电阻。在LiV₃O₈/聚三苯胺复合材料中，17 wt%的LVO/PTPAn复合材料显示出最大的d₁₀₀间距。电化学结果表明，17 wt%的LVO/PTPAn复合材料在60 mA·g⁻¹的电流密度下保持271 mAh·g⁻¹的放电容量，并且在240 mA·g⁻¹的电流密度下经过50次循环后仍保持236 mAh·g⁻¹，而纯LiV₃O₈样品分别仅保留169和148 mAh·g⁻¹。电化学阻抗谱（EIS）结果表明，17 wt%的LVO/PTPAn复合材料显示出电荷转移电阻降低以及Li⁺离子扩散能力增强，因此与纯LiV₃O₈样品相比表现出更好的倍率性能和循环性能。