Laser Raman Spectral Investigations of the Carbon Structure of LiFePO4/C Cathode Material
YANG Chao, LI Yong-mei, ZHAO Quan-feng, GAN Xiang-kun, YAO Yao-chun*
Kunming University of Science and Technology, Faculty of Metalurgcal and Engergy Engineering, National Engineering Laboratory for Vacuum Metallurgy, Kunming 650093, China
Abstract：In the present paper, Laser Raman spectral was used to study the carbon structure of LiFePO4/C positive material. The samples were also been characterized by X-ray diffraction(XRD), scanning electron microscope(SEM), selected area electron diffraction(SEAD) and resistivity test. The result indicated that compared with the sp2/sp3 peak area ratios the ID/IG ratios are not only more evenly but also exhibited some similar rules. However, the studies indicated that there exist differences of ID/IG ratios and sp2/sp3 peak area ratios among different points in the same sample. And compared with the samples using citric acid or sucrose as carbon source, the sample which was synthetized with mixed carbon source(mixed by citric acid and sucrose) exhibited higher ID/IG ratios and sp2/sp3 peak area ratios. Also, by contrast, the differences of ID/IG ratios and sp2/sp3 peak area ratios among different points in the same sample are less than the single carbon source samples’ datas. In the scanning electron microscopy (sem) and transmission electron microscopy (sem) images, we can observed the uneven distributions of carbon coating of the primary particles and the secondary particles, this may be the main reason for not being uniform of difference data in the same sample. The obvious discreteness will affect the normal use of Raman spectroscopy in these tests.
Key words：Laser Raman spectral;LiFePO4/C;Carbon coating;Degree of graphitization
杨 超，李永梅，赵泉峰，干祥坤，姚耀春* . 激光拉曼光谱对LiFePO4/C正极材料包覆碳结构的研究 [J]. 光谱学与光谱分析, 2013, 33(10): 2700-2704.
YANG Chao, LI Yong-mei, ZHAO Quan-feng, GAN Xiang-kun, YAO Yao-chun* . Laser Raman Spectral Investigations of the Carbon Structure of LiFePO4/C Cathode Material. SPECTROSCOPY AND SPECTRAL ANALYSIS, 2013, 33(10): 2700-2704.
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