锂离子电池用掺锡锂钛氧化物的研究

Researches on tin-doping lithium titanium oxide for Li-ion batteries

采用高温固相法在850℃下合成掺锡锂钛复合氧化物作为锂离子电池负极材料,并对材料进行了X射线衍射分析、SEM、电化学阻抗测试、循环伏安测试及恒流充放电测试。锡的掺杂并未改变材料的晶体结构,但降低了材料的规整度。实验结果表明:锡的掺杂在一定程度上改善了锂钛氧化物的电化学性能,降低了电极极化,在电极表面并未形成钝化膜。其中以掺杂比为Sn∶Ti=1∶5(原子比)的材料性能最好,首次放电容量达到165mAh/g以上,经过50次循环后,容量仍保持在157 mAh/g。

Tin-doping lithium titanate materials were synthesized by a solid-state method, and then characterized by XRD, SEM, AC impedance spectroscopy, cyclic vohammetry and galvanostatic cycling tests. The tin doping didn＇t change the crystal structure, but weakened the crystallinity of the material. The results indicated that the tin-doping materials had better electrochemical performance and weaker electrode polarization and no passivating film was found over the electrode. Among them, the sample with the Sn：Ti=1：5（molar ratio） was the best. It had an initial capacity of 165 mAh/g, and retained 157 mAh/g after 50 cycles.