科研之友
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摘要
A monodispersed nano-sized hexahedral LiFePO4 of regular angularity was prepared through hydrothermal process. Different carbon precursors were employed to create carbon-coating layers onto the nanoparticles to improve the electrochemical performances of the material. Structure and morphology of the LiFePO4 material without and with carbon-coating layer were studied using a combination of X-ray diffraction, scanning electron microscopy, transmission electron microscopy, and Raman spectroscopy. It confirms that carbon-coating plays an important role inhibiting the agglomeration of the nanoparticles. A uniform carbon-coating layer of higher graphitization degree was developed on the LiFePO4 particles with sucrose precursor. The electrode exhibits discharge capacities of 148.3 mA h g(-1), 138.7 mA h g(-1), 117.8 mA h g(-1) at 0.1 C, 1 C and 10 degrees C, respectively. Very close Li ion diffusion coefficient of around 8 x 10(-14) cm(2) s(-1) for all the LiFePO4/C composites with different carbon sources implies that the improved power capability is mainly attributed to the small particle size and low contact resistance between the LiFePO4 nanoparticles.
- 出版日期2013-12-5
- 单位苏州大学
