CAJ | 학술논문

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.
이삼개철염위철원,채용다원순환원법재저온하제비출료구유불동장경비적봉상LiFePO4재료.통과X사선연사(XRD)、소묘전경(SEM)、투사전경(TEM)、순배복안(CV)、교류조항보(EIS)화항전류충방전측시등수단분석료불동회류반응시간하제비출적전구체화최종적LiFePO4/C양품.결과표명：회류반응시간대LiFePO4적형모화특성유명현적영향.통과파회류반응시간종4 h연장지16 h,재료적형모유불규칙적단봉상과립변위규칙적장봉상과립,차봉적직경명현변소.당회류반응시간위10 h시,양품복합료다충형모,유리우전자적전수,재저배솔하구유우수적성능,0.1C방전비용량위163 mAh?g-1；당회류반응시간위16 h시,양품구유최대적장경비,유리우리리자적확산,재고배솔하구유량호적성능,1C、3C、5C、10C、20C배솔하방전비용량분별위135、125、118、110、98 mAh?g-1,순배성능량호,궤호무쇠감.
Rod-like LiFePO4/C particles with different aspect ratios were synthesized by control ing the reflux reaction time in polyol medium at a low temperature, using an Fe3 + salt as the iron source. The precursors and final LiFePO4/C samples were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), and galvanostatic charge-discharge test. The results show that the reflux reaction time has a significant effect on the characteristics of the LiFePO4 precursors and electrochemical performance of the final LiFePO4/C samples. The morphology of the precursors is transformed from irregular short rod-like particles into regular long rod-like particles, and the aspect ratios of the rods increase with increasing reflux reaction time from 4 to 16 h. At a reflux reaction time of 10 h, the material contains multifarious morphologies, which is beneficial to the electron transmission, and displays an excellent electrochemical performance at low discharge rates, the discharge capacity is 163 mAh?g-1 at 0.1C rate. Extension of the reflux reaction time to 16 h, the material reveals the biggest aspect ratio, which is conducive to the diffusion of lithium ions, and gives good electrochemical performance at high discharge rates, the discharge capacities are measured to be 135, 125, 118, 110, and 98 mAh?g-1 at 1C, 3C, 5C, 10C, and 20C rates, respectively, revealing good cycling performance and little capacity fading.