【摘要】 本文主要通过水热法制备了锂离子电池正极材料Li3V2-2x/3Mgx(PO4)3/C,并研究了掺杂金属元素Mg对Li3V2(PO4)3晶体结构和电性能的影响。结果表明,当Mg含量x=0.45(质量分数,下同)时,且在温度为750℃焙烧6 h的条件下所制备的样品具有较好的晶体结构、微观形貌和电化学性能。镁掺杂量在一定范围内变化不会影响磷酸钒锂本身的单斜结构。在3.0~4.8 V、0.1 C倍率下,Li3V1.70Mg0.45(PO4)3/C复合材料首次放电比容量高达154.4 mAh·g-1,首次库伦效率为94.32%,在不同倍率下循环25次之后的容量依然可以达到112.8 mAh·g-1。掺杂镁的样品与未掺杂的样品相比,容量和循环倍率性能均有了很大程度的提高。更多还原

【Abstract】 Cathode material Li3V2-2x/3Mgx( PO4)3/C for lithium-ion batteries was prepared by hydrothermal method,and the effects of the Mg-doping on crystal structure,morphology and electrochemical properties of cathode materials were studied. The results show that the sample with the Mg content of x = 0. 45,and prepared at 750 ℃ for 6 h has a better crystal structure,morphology and electrochemical performance. It is also found that adding an appropriate amount of Mg does not change the monoclinic structure of Li3V2( PO4)3. The initial discharge capacity of Li3V1. 70Mg0. 45( PO4)3/C composites is up to 154. 4 mAh·g- 1at 3. 0 ~ 4. 8 V( 0. 1 C magnification),and the first coulombic efficiency is 94. 32%. After charged /discharged at different magnifications for 25 cycles,the sample retains a discharge specific capacity of 112. 8 mAh · g- 1. Both capacity and cycle rate capability have been improved obviously compared with the undoped samples.更多还原