摘要： Carbon-coated LiFePO 4 cathode materials were prepared by a solid-state method incorporating different sizes of polystyrene (PS) spheres as carbon sources. In scanning electron microscope images, small PS spheres appear more effective at preventing aggregation of LiFePO 4 particles. From transmission electron microscopy images, it was found that the LiFePO 4 particles were completely uniformly coated with 5-nm carbon layer when the carbon source was 0.22 μm PS spheres. When the size of PS sphere was increased to 2.75 μm, a network of carbon was formed and wrapped around the LiFePO 4 to create a conductive web. Raman spectroscopy and four-point probe conductivity measurement showed that using larger sizes of PS spheres as carbon sources leads to greater conductivity of LiFePO 4 /C. The LiFePO 4 precursor sintered with 0.22 μm PS spheres delivered an initial discharge capacity of 145 mAh g −1 at a 0.2 C rate, but it only sustained 289 cycles at 80% capacity. When the diameter of PS spheres was increased to 2.75 μm, the discharge capacity of LiFePO 4 /C decreased, but the cycle life reached 755 cycles, the highest number in this work probably due to the network formation of carbon wrapping around LiFePO 4 particles. 其他題名： J Solid State Electrochem 出版者： Berlin/Heidelberg: Springer-Verlag 出版日期： 2012-05 出處： Journal of solid state electrochemistry, 2012-05, Vol.16 (5), p.1857-1862 版權： Springer-Verlag 2012 識別號： ISSN: 1432-8488 識別號： EISSN: 1433-0768 識別號： DOI: 10.1007/s10008-011-1621-3
