CAJ | 학술논문

通过低温溶剂热法和高温热处理技术合成了橄榄石结构的LiFePO4/carbon (C-LiFePO4)纳米材料.在此基础上,通过溶液共混法制备了一种新型的聚三苯胺(PTPAn)修饰包覆的C-LiFePO4复合锂离子电池正极材料(C-LiFePO4/PTPAn).利用X射线衍射(XRD)、扫描电镜(SEM)、透射电镜(TEM)、电化学阻抗谱(EIS)以及恒电流充放电等测试方法,考察PTPAn包覆量对C-LiFePO4/PTPAn复合正极材料性能的影响.结果表明：通过溶液共混法PTPAn能够致密地包覆在C-LiFePO4表面,形成一个有效的电子/离子传输通道从而有效提高C-LiFePO4基复合材料的电化学活性.所有样品中C-LiFePO4/10%(w) PTPAn作为正极材料呈现出最佳的电化学性能,在0.1C倍率恒流充放电下材料首次放电比容量为154.5 mAh?g-1,在10C高倍率恒流充放电下材料的放电比容量达到114.2 mAh?g-1.当C-LiFePO4/PTPAn复合材料表面包覆的PTPAn含量进一步增加,复合材料的电化学性能出现下降的趋势.电化学阻抗测试表明PTPAn包覆层明显减小了C-LiFePO4电极的电荷转移电阻.
통과저온용제열법화고온열처리기술합성료감람석결구적LiFePO4/carbon (C-LiFePO4)납미재료.재차기출상,통과용액공혼법제비료일충신형적취삼분알(PTPAn)수식포복적C-LiFePO4복합리리자전지정겁재료(C-LiFePO4/PTPAn).이용X사선연사(XRD)、소묘전경(SEM)、투사전경(TEM)、전화학조항보(EIS)이급항전류충방전등측시방법,고찰PTPAn포복량대C-LiFePO4/PTPAn복합정겁재료성능적영향.결과표명：통과용액공혼법PTPAn능구치밀지포복재C-LiFePO4표면,형성일개유효적전자/리자전수통도종이유효제고C-LiFePO4기복합재료적전화학활성.소유양품중C-LiFePO4/10%(w) PTPAn작위정겁재료정현출최가적전화학성능,재0.1C배솔항류충방전하재료수차방전비용량위154.5 mAh?g-1,재10C고배솔항류충방전하재료적방전비용량체도114.2 mAh?g-1.당C-LiFePO4/PTPAn복합재료표면포복적PTPAn함량진일보증가,복합재료적전화학성능출현하강적추세.전화학조항측시표명PTPAn포복층명현감소료C-LiFePO4전겁적전하전이전조.
An olivine LiFePO4/carbon (C-LiFePO4) nanocrystal ine material was prepared using a low-temperature solvothermal method, fol owed by a high-temperature post-annealing process. Then polytriphenylamine (PTPAn)-modified C-LiFePO4 (C-LiFePO4/PTPAn) was prepared, as a composite for novel cathodes for lithium-ion batteries, by solution blending of the C-LiFePO4 nanocrystal ine material and the electroactive conducting polymer PTPAn. The effects of PTPAn coating of the C-LiFePO4/PTPAn samples were investigated using X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), electrochemical impedance spectroscopy (EIS), and galvanostatic charge-discharge testing. The results indicated that the solution blending method produced a compact PTPAn coating on the C-LiFePO4, providing an effective electronic/ionic conducting pathway and enhancing the electrochemical activities of C-LiFePO4-based composites. The C-LiFePO4/10%(w) PTPAn electrode displayed an improved initial discharge capacity of 154.5 mAh?g-1 at 0.1C, a superior high-rate performance discharge capacity of 114.2 mAh?g-1 at 10C, and excellent cycling stability. With further increases in the PTPAn content of the coating on the C-LiFePO4/PTPAn composite, the electrochemical properties of the composite decreased. Electrochemical impedance measurements also demonstrated that the PTPAn coating significantly decreased the charge-transfer resistance of the C-LiFePO4 electrode.