A monodispersed nano-hexahedral LiFePO4 with improved power capability by carbon-coatings

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. (C) 2013 Elsevier B.V. All rights reserved.