焙烧时间对Li_(1.2)V_3O_8电极材料的结构、颗粒分布和电化学性能的影响

以V2O5水凝胶和LiOH.H2O为原料,采用溶胶-凝胶法制备了Li1.2V3O8前驱体,控制在300℃下焙烧不同时间成功地获得了锂二次电池正极材料Li1.2V3O8.利用XRD(粉末X-射线衍射)、SEM(扫描电子显微镜)和LPSA(激光粒度分析)对产物进行了物理表征;采用恒流充放电技术评价了其电化学性能.结果表明,与其它焙烧时间的样品相比,焙烧10 h的样品具有较弱的(100)衍射峰强度、较大的d100层间距、较小的颗粒尺寸和较窄的粒度分布区间,其最高放电容量为320 mAh.g-1,并表现出了良好的循环性能.

Influence of Calcination Time on the Structure, Particles Distribution and Electrochemical Performances of Li1.2V3O8 Cathode Material

The precursors Li1.2V3O8 are synthesized by the sol-gel reaction of V2O5 hydrogel and LiOH·H2O.Li1.2V3O8 powders as cathode materials for lithium secondary batteries are successfully obtained by calcining the precursors at 300 ℃ for different times.The thus-obtained samples are physically-characterized by means of XRD(powder X-ray diffraction),SEM(scanning electron microscope) and LPSA(laser particles size analysis),and the electrochemical performances of the samples are assessed by the galvanostatic discharge-charge technique.The results indicate that the sample made at 300 ℃ for 10 h displays lower intensity of diffraction peak(100),larger interlayer spacing of d100,smaller particles size and narrower particles distribution range compared to the samples obtained at 300 ℃ for other calcination times.The sample synthesized at 300 ℃ for 10 h has a maximum discharge capacity of 320 mAh·g-1 and exhibits a good cyclability.