以三价铁盐为铁源,采用多元醇还原法在低温下制备出了具有不同长径比的棒状LiFePO4材料.通过X射线衍射(XRD)、扫描电镜(SEM)、透射电镜(TEM)、循环伏安(CV)、交流阻抗谱(EIS)和恒电流充放电测试等手段分析了不同回流反应时间下制备出的...以三价铁盐为铁源,采用多元醇还原法在低温下制备出了具有不同长径比的棒状LiFePO4材料.通过X射线衍射(XRD)、扫描电镜(SEM)、透射电镜(TEM)、循环伏安(CV)、交流阻抗谱(EIS)和恒电流充放电测试等手段分析了不同回流反应时间下制备出的前驱体和最终的LiFePO4/C样品.结果表明:回流反应时间对LiFePO4的形貌和特性有明显的影响.通过把回流反应时间从4 h延长至16 h,材料的形貌由不规则的短棒状颗粒变为规则的长棒状颗粒,且棒的直径明显变小.当回流反应时间为10 h时,样品复合了多种形貌,有利于电子的传输,在低倍率下具有优秀的性能,0.1C放电比容量为163 mAh g-1;当回流反应时间为16 h时,样品具有最大的长径比,有利于锂离子的扩散,在高倍率下具有良好的性能,1C、3C、5C、10C、20C倍率下放电比容量分别为135、125、118、110、98 mAh g-1,循环性能良好,几乎无衰减.展开更多
Based on the method of in situ polymerization synthesis combined with two-step sinter-ing process,LiFe_(1-x)V_(x)(PO_(4))_(3-y)/F_(y)/C was prepared.The effects of V and F co-doping on the structure,morphology,and ele...Based on the method of in situ polymerization synthesis combined with two-step sinter-ing process,LiFe_(1-x)V_(x)(PO_(4))_(3-y)/F_(y)/C was prepared.The effects of V and F co-doping on the structure,morphology,and electrochemical performances of LiFePO4/C were in-vestigated by X-ray diffraction,Fourier transform infrared spectra,scanning electron mi-croscope,charge/discharge tests,and electrochemical impedance spectroscopy,respectively.The results indicated that the V and F co-doping did not destroy the olivine structure of LiFePO4/C,but it can stabilize the crystal structure,decrease charge transfer resistance,enhance Li ion diffusion velocity,further improve its cycling and high-rate capabilities of LiFePO4/C.展开更多
基金The project was supported by the Sichuan University Funds for Young Scientists,China(2011SCU11081)Research Fund for the Doctoral Program of Higher Education,Ministry of Education,China(20120181120103)~~
文摘以三价铁盐为铁源,采用多元醇还原法在低温下制备出了具有不同长径比的棒状LiFePO4材料.通过X射线衍射(XRD)、扫描电镜(SEM)、透射电镜(TEM)、循环伏安(CV)、交流阻抗谱(EIS)和恒电流充放电测试等手段分析了不同回流反应时间下制备出的前驱体和最终的LiFePO4/C样品.结果表明:回流反应时间对LiFePO4的形貌和特性有明显的影响.通过把回流反应时间从4 h延长至16 h,材料的形貌由不规则的短棒状颗粒变为规则的长棒状颗粒,且棒的直径明显变小.当回流反应时间为10 h时,样品复合了多种形貌,有利于电子的传输,在低倍率下具有优秀的性能,0.1C放电比容量为163 mAh g-1;当回流反应时间为16 h时,样品具有最大的长径比,有利于锂离子的扩散,在高倍率下具有良好的性能,1C、3C、5C、10C、20C倍率下放电比容量分别为135、125、118、110、98 mAh g-1,循环性能良好,几乎无衰减.
文摘Based on the method of in situ polymerization synthesis combined with two-step sinter-ing process,LiFe_(1-x)V_(x)(PO_(4))_(3-y)/F_(y)/C was prepared.The effects of V and F co-doping on the structure,morphology,and electrochemical performances of LiFePO4/C were in-vestigated by X-ray diffraction,Fourier transform infrared spectra,scanning electron mi-croscope,charge/discharge tests,and electrochemical impedance spectroscopy,respectively.The results indicated that the V and F co-doping did not destroy the olivine structure of LiFePO4/C,but it can stabilize the crystal structure,decrease charge transfer resistance,enhance Li ion diffusion velocity,further improve its cycling and high-rate capabilities of LiFePO4/C.
