Structural Analysis and Electrochemical Performance of Li2CoPO4F Cathode Materials
Structural Analysis and Electrochemical Performance of Li2CoPO4F Cathode Materials
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DOI：
10.1016/j.electacta.2014.02.026
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发表时间：
2014-05
影响因子：
6.6
通讯作者：
Q. D. Truong;M. Devaraju;Yoshiyuki Ganbe;T. Tomai;I. Honma
中科院分区：
文献类型：
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作者：
Q. D. Truong;M. Devaraju;Yoshiyuki Ganbe;T. Tomai;I. Honma
采用溶胶-凝胶法和固相反应相结合的两步法合成了Li 2CoPO 4F正极材料。X射线衍射（XRD）分析表明，Li 2CoPO 4F具有良好的正交晶系晶体结构，Pnmaspace基团。从高分辨率透射电子显微镜（HRTEM）图像;{001}和{100}的晶格条纹被很好地分辨。HRTEM图像和选区电子衍射（SAED）图案揭示了具有有序正交晶体结构的Li 2CoPO 4F的高度结晶性质。采用高角环形暗场扫描透射电子显微镜（HAADF-STEM）对Li 2CoPO 4F中的Co原子链进行了观察。拉曼光谱和傅里叶变换红外光谱（FTIR）表明了Li 2CoPO 4F结构的对称性和稳定性。Li 2CoPO 4F正极材料在C/10倍率下的初始放电容量为91 mAhg− 1，具有良好的循环性能。Li 2CoPO 4F的放电曲线在5.0 V处显示出平台;揭示了其作为潜在高压阴极的重要性。
Li2CoPO4F cathode materials have been synthesized by a two-step method combining a sol-gel route and solid state reaction. X-ray diffraction (XRD) analysis confirmed that the Li2CoPO4F was well-crystallized in orthorhombic crystal structure withPnmaspace group. From the high resolution transmission electron microscopy (HRTEM) image; the lattice fringes of {001} and {100} are well-resolved. HRTEM image and selected area electron diffraction (SAED) pattern reveal the highly crystalline nature of Li2CoPO4F having an ordered orthorhombic crystal structure. The Co atoms chains of Li2CoPO4F have been observed using high angle annular dark-field scanning transmission electron microscopy (HAADF-STEM). The Raman and Fourier transform infrared spectroscopy (FTIR) spectra indicate the symmetry and stability of the Li2CoPO4F structure. The Li2CoPO4F cathode materials delivered an initial discharge capacity of 91 mAhg−1at C/10 rate with good cyclic performance. The discharge profile of Li2CoPO4F shows a plateau at 5.0 V; revealing its importance as potentially high-voltage cathode.