(浙江大学 硅材料国家重点实验室， 杭州 310027)
摘 要: 以分析纯的FeSO4、 H3PO4和LiOH为原料，用水热合成法得到纯度高、 结晶好的纳米LiFePO4。 X射线衍射和SEM分析结果表明， 当实验温度为120~150 ℃， 时间为5~15 h时， 随反应温度的提高和反应时间的延长， LiFePO4从不规则的纳米颗粒团聚体逐渐生长为厚200 nm、长800 nm左右的规则矩形薄片。 研究发现， 在合成过程中， 首先合成中间产物Li3PO4， 然后与Fe2+反应形成LiFePO4。 水热合成产物经550 ℃聚丙烯裂解碳包覆处理后， 以0.05 C充放电， 可逆电容量达到163 mA·h·g-1，以0.5 C充放电，可逆电容量达到144 mA·h·g-1。
关键字: 锂离子电池； 正极材料； 水热合成； 形貌
LiFePO4 prepared by hydrothermal synthesis
（ State Key Laboratory of Silicon Materials, Zhejiang University,
Hangzhou 310027, China）
Abstract: High-pure and well-crystalline nano-LiFePO4 was prepared by hydrothermal method using analytically pure FeSO4, H3PO4 and LiOH as the precursors. The results through XRD and SEM analyses show that, with the increase of the reaction temperature from 120 ℃ to 150 ℃ and time from 5 h to 15 h, the synthesized LiFePO4 particles grow from the irregular congeries of nano-crystals to the rectangular slabs with thickness of about 200 nm and side-length of about 800 nm. The intermediate product Li3PO4 is first synthesized during the reaction, then it reacts with Fe2+ to form the high-pure LiFePO4. A reversible capacity of 163 mA·h·g-1 at 0.05 C or 144 mA·h·g-1 at 0.5 C has been obtained after the carbon coated with LiFePO4 is prepared by decomposing polypropylene with the LiFePO4 powders at 550 ℃.
Key words: lithium-ion battery; cathode material; hydrothermal synthesis; morphology
