Synthesis and properties of Co-doped LiFePO4 as cathode material via a hydrothermal route for lithium-ion batteries
Synthesis and properties of Co-doped LiFePO4 as cathode material via a hydrothermal route for lithium-ion batteries
复制标题
DOI：
10.1016/j.jallcom.2011.10.037
复制
发表时间：
2012-02
影响因子：
6.2
通讯作者：
R. Zhao;I. Hung;Yi-Ting Li;Hongyu Chen;Chun-Peng Lin
中科院分区：
文献类型：
--
作者：
R. Zhao;I. Hung;Yi-Ting Li;Hongyu Chen;Chun-Peng Lin
采用水热法在还原气氛下合成了一系列橄榄石型LiFe 1 − xCoxPO 4复合材料。通过X射线衍射表征了所制备样品的结构。分别通过扫描电子显微镜、高分辨率透射电子显微镜和相应的EDS图谱观察形貌、粒度和元素浓度。采用拉曼光谱研究了碳包覆LiFe 1 − xCoxPO 4的表面信息。利用交流阻抗谱和充放电测试仪研究了样品在室温下的电化学性能。LiFe_（3/4）Co_（1/4）PO_（4/C）在0.1C倍率下的放电容量为170mAh/g。LiFe1 − xCoxPO4可以达到比纯LiFePO4更高的放电平台（约3.5V）（约3.4V）。结果表明，Co掺杂样品在低放电速率下表现出改善的电化学性能。但XPS结果表明，随着掺杂量的增加，Li-O能带进一步稳定，不利于化合物的锂扩散系数。
A series of olivine LiFe1−xCoxPO4composites were synthesised by a hydrothermal route under reductive atmosphere. The structure of the prepared samples was characterised by X-ray diffraction. Morphology, particle size, and elemental concentration were observed by scanning electron microscopy, high-resolution transmission electron microscopy, and corresponding EDS mapping, respectively. Raman spectroscopy was employed to study the surface information of the carbon-coated LiFe1−xCoxPO4. The electrochemical properties of the samples were studied by AC impedance spectroscopy and charge–discharge instruments at room temperature. The discharge capacity of LiFe3/4Co1/4PO4/C is 170mAh/g at rate of 0.1C. LiFe1−xCoxPO4can achieve a higher discharge plateau (∼3.5V) than does pure LiFePO4(∼3.4V). The results indicate that the Co-doped sample exhibits improved electrochemical performance at low discharge rates. However, XPS results show that the Li–O band stabilises further as the doping amount increase, which is not beneficial to the lithium diffusion coefficient of the compound.