碳源对液相法制备Li_3V_2(PO_4)_3/C的影响

Effects of sources and addition amount of carbon on performances of Li_3V_2(PO_4)_3/C

以4种不同种类的有机物(柠檬酸、水杨酸、聚丙烯酸、蔗糖)为碳源,通过液相反应合成Li3V2(PO4)3/C复合材料。研究了不同碳源对复合材料的晶型结构、形貌及电化学性能的影响。结果表明,碳源对Li3V2(PO4)3/C材料的晶型结构没有影响,但对电化学性能影响较明显,其中采用柠檬酸为碳源制得的Li3V2(PO4)3/C复合材料电化学性能最好。进一步研究了柠檬酸的加入量对复合材料的电化学性能的影响,发现当柠檬酸加入量为钒与碳的物质的量比为1∶4时,样品的平均粒径较小,电化学性能最好,0.1C首次放电比容量为123.59mAhg-1,0.5C首次放电比容量也高达117.27mAhg-1,循环10次后,仍保持在117.19mAhg-1,容量几乎没有衰减,10C时比容量仍有105.43mAhg-1。

Li3V2（PO4）3/C composite material was synthesized by four different organic carbon sources（such as citric acid,salicylic acid,polyacrylic acid and sucrose）.Effects of different carbon sources on crystal structure and electrochemical performances of Li3V2（PO4）3/C material were studied.Results showed that the kind of carbon source didn＇t affect the crystal structure of Li3V2（PO4）3 material but obviously affected its electrochemical performances,and the sample with citric acid as carbon source showed the best electrochemical performances.Effects of different addition amounts of citric acid on electrochemical performances of Li3V2（PO4）3/C material were also further studied.Results indicated that the sample with addition of citric acid as n（V）∶n（C）=1∶4 had small size,uniform distribution and best electrochemical performances.First discharge specific capacity was 123.59 mAhg-1 at 0.1C,which was also up to 117.27 mAh g-1 at 0.5C and it was still maintained at 117.19 mAhg-1after cycling 10 times,the capacity staied the same,and when discharged at 10C the capacity also kept at 105.43 mAh g-1.