(浙江大學(xué) 硅材料國家重點(diǎn)實驗室， 杭州 310027)
摘 要: 以分析純的FeSO4、 H3PO4和LiOH為原料，用水熱合成法得到純度高、 結(jié)晶好的納米LiFePO4。 X射線衍射和SEM分析結(jié)果表明， 當(dāng)實驗溫度為120~150 ℃， 時間為5~15 h時， 隨反應(yīng)溫度的提高和反應(yīng)時間的延長， LiFePO4從不規(guī)則的納米顆粒團(tuán)聚體逐漸生長為厚200 nm、長800 nm左右的規(guī)則矩形薄片。 研究發(fā)現(xiàn)， 在合成過程中， 首先合成中間產(chǎn)物L(fēng)i3PO4， 然后與Fe2+反應(yīng)形成LiFePO4。 水熱合成產(chǎn)物經(jīng)550 ℃聚丙烯裂解碳包覆處理后， 以0.05 C充放電， 可逆電容量達(dá)到163 mA·h·g-1，以0.5 C充放電，可逆電容量達(dá)到144 mA·h·g-1。
關(guān)鍵字: 鋰離子電池； 正極材料； 水熱合成； 形貌
LiFePO4 prepared by hydrothermal synthesis
MI Chang-huan, TU Jian, TU Jiang-ping
（ 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
