锂离子电池Li_3V_(2-x)Al_x(PO_4)_3正极材料合成及性能研究

Synthesis and Properties of Li_3V_(2-x)Al_x(PO_4)_3 Cathode Material for Lithium-ion Battery

以V_2O_5、LiOH、NH_4H_2PO_4、Al(OH)_3和柠檬酸为原料采用溶胶-凝胶法合成V位掺杂Al3+的Li_3V_(2-x)Al_x(PO_4)_3/C复合材料,仔细研究Al3+掺杂对磷酸钒锂材料电化学性能的影响,确定最佳的Al掺杂量。同时借助各种分析手段(如XRD、SEM、TG-DTA)对掺杂后Li_3V_(2-x)Al_x(PO_4)3/C材料结构变化进行探究,深入理解V位掺杂对电化学性能产生作用的内在机理。Li_3V_2-xAlx(PO_4)_3/C(x=0,0.02,0.05,0.1,0.15,0.2)首次放电比容量分别为103.7 m Ah/g,105.7 m Ah/g,108.4 m Ah/g,141.1 m Ah/g,130.1 Ah/g,124.8 m Ah/g。在一定范围内,随着Al3+量的提高,相应的Li3V2-xAlx(PO4)3/C的首次放电比容量也不断的增加。

Al-doped Li3V2-xAlx（PO4）3/C compounds was synthesized by sol-gel method using V2Os, LiOH, NH4H2POa, AI（OH）） and citric acid as the raw materials. The structure and morphology of these samples were characterized by XRD and SEM. The results of TG-DTA suggest that AI-doped Li3V2-xAlx（PO4）3/C had been successfully synthesized at the relative lower sintering temperature （700 ℃）. At 0.2 C the initial discharge capacities range ofprepared Li3V2-xAlx（PO4））/Cis between to 103.7 and 141.1 mAh/g. The initial specific capacity increases with AI content at a lower current rate.