| Li3PO4表面修饰提高球形LiNi0.5Mn1.5O4正极材料的性能 |
| Li3PO4 Surface Modification to Improve Performance of LiNi0.5Mn1.5O4 Cathode Material |
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| 摘要: 通过共沉淀法制备了球形LiNi0.5Mn1.5O4@Li3PO4复合材料,并采用X射线衍射(XRD)、扫描电镜(SEM)、红外光谱(FT-IR)、循环伏安(CV)、电化学阻抗谱(EIS)及充放电测试研究了其结构与电化学性能.XRD和SEM表明,Li3PO4包覆影响了球形LiNi0.5Mn1.5O4的晶格常数.CV和EIS表明,质量百分数5% Li3PO4包覆的LiNi0.5Mn1.5O4具有比纯LiNi0.5Mn1.5O4更高的锂离子嵌脱可逆性,更大的锂离子扩散系数和更小的电荷转移电阻,说明在锂离子扩散过程中,质量百分数5%Li3PO4包覆的LiNi0.5Mn1.5O4具有更高的电子电导率.充放电测试表明,原位Li3PO4改性提高了材料的电子电导率、电化学活性,进而提高了高倍率放电容量.质量百分数5% Li3PO4包覆的LiNi0.5Mn1.5O4提高的电化学性能归因于Li3PO4的包覆、纳米颗粒组成球形的粒径引起的高的电子电导率和小的电化学极化. |
| 关键词: 锂离子电池 正极材料 表面包覆 电化学性能 |
| 基金项目: |
| Abstract: Spherical LiNi0.5Mn1.5O4@Li3PO4 composite was prepared by a co-precipitation method. The structure and electrochemical performance were investigated by X-ray powder diffraction (XRD), scanning electron microscope (SEM), FT-IR spectroscopy, cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS) and charge-discharge measurements. XRD and SEM shows that Li3PO4 coating influence the lattice parameter of LiNi0.5Mn1.5O4 composed of spherical particle size. CV and EIS imply that 5% (mass percent) Li3PO4-coated LiNi0.5Mn1.5O4 has higher reversible intercalation and deintercalation of Li+, larger lithium-ion diffusion coefficient and smaller charge transfer resistance corresponding to a much higher conductivity than those of pristine LiNi0.5Mn1.5O4 corresponding to the extraction of Li+ ions. Charge-discharge test reveals that the in situ Li3PO4 modifying improves the electronic conductivity of the electrode in the local environment, electrochemical activity, and then results in their relatively higher capacity at high charge-discharge rate. The enhanced performance of 5% (mass percent) Li3PO4-coated LiNi0.5Mn1.5O4 is ascribed to the improved electronic conduction and the reduced polarization resulting from the Li3PO4 modification together with sphere-like particles composed of nano particle LiNi0.5Mn1.5O4. |
| Keywords: lithium-ion battery cathode materials surface coating electrochemical performance |
| 投稿时间：2015-08-31 修订日期：2015-11-26 |
| 摘要点击次数: 1800 |
| 全文下载次数: 1529 |
| 任宁,卢世刚.Li3PO4表面修饰提高球形LiNi0.5Mn1.5O4正极材料的性能[J].无机化学学报,2016,32(3):499-507. |
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