LiFe_1-xMg_xPO₄/C的制备和性能研究(英文)

Synthesis and Characterization of LiFe_(1-x)Mg_xPO_4/C Composite Cathode Materials

以乙酸镁为掺杂元素、蔗糖为碳源,采用固相反应法制备镁掺杂磷酸铁锂包覆碳复合材料LiFe1-xMgxPO4/C（x=0.01,0.02,0.03,0.04）。利用X射线衍射（XRD）分析其结构,扫描电镜（SEM）观察其形貌,恒电流法测定其电化学性能。研究结果表明镁离子掺杂没有影响材料的结构,而是提高了其放电容量和循环性能。在这些样品中,LiFe0.98Mg0.02PO4/C的容量最高,首次放电达到140.0mAh/g;并且在80次循环后容量没有衰减反而增加到148.6mAh/g左右。

LiFe_(1-x)Mg_xPO_4/C(x =0.01,0.02,0.03,0.04) composites were prepared by solid state reaction method using magnesium acetate as dopant and sucrose as carbon source.The structural,morphological and electrochemical properties were investigated by means of X-ray powder diffraction(XRD),scanning electron microscopy(SEM) and constant current charge-discharge cycling.The results indicate that magnesium ion dopant does not affect the structure of the material but considerably improves its capacity and cycle performance.Among the samples,LiFe_(0.98)Mg_(0.02)PO_4/C shows the best capacity of 140.0 mAh/g in the first discharge and its capacity increases to 148.6 mAh/g without capacity fading after 80 cycles.