摘要
采用水热法合成了LiFe_(1-x)V_xPO_4/C,粉体颗粒呈球形,直径约为300 nm,结果表明钒掺杂没有改变晶体结构,引入V显著提高了材料的电化学性能,其中LiFe_(0.95)V_(0.05)PO_4/C具有最好的倍率和循环性能,在1.0 C经100次循环后放电比容量仍为129.5 m h·g^(-1),容量保持率高达96.9%。循环伏安测试表明V掺杂提高了Li^+的扩散速率,结合水热法制备的颗粒尺寸小且均匀的优点,使得Li^+的扩散路径大大缩短,由此提高了材料的电化学性能。
LiFe_(1-x)V_xPO_4/C was synthesized by a hydrothermal process. The obtained particle has spherical shape and the size of powder is about 300 nm. The crystallographic evidence indicates that the introduction of V does not significantly change the host crystal structure. V-doping can improve the performance of material immensely. Particularly, the LiFe_(0.95)V_(0.05)PO_4/C exhibits the best rate and cycle performance with a specific discharge capacity of 129.5 mAhg^(-1) at 1.0 C after 100 cycles; the capacity retention ratio is higher than 96.9%. From the CV, the V-doping improves the Li+ ionic diffusion coefficient. The particle prepared by hydrothermal method is small and uniform, which reduces the transport length of Li+ greatly. Thus, the electrochemical properties of the materials are improved. The experimental results provide a new and effective way of LiFePO_4 doped V.
出处
《稀有金属材料与工程》
SCIE
EI
CAS
CSCD
北大核心
2015年第S1期93-96,共4页
Rare Metal Materials and Engineering
基金
国家自然科学基金(51372014)
