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The olivine-typed cathode materials of LiFePO4were prepared via solid-state reaction under argon atmosphere and co-doped by manganese and fluorine to improve their electrochemical performances. The crystal structure, morphology, and electrochemical properties of the prepared samples were investigated using X-ray diffraction, scanning electron microscopy, Fourier transform infrared spectrum, X-ray photoelectron spectroscopy, cyclic voltammetry, and charge–discharge cycle measurements. The result showed that the electrochemical performance of LiFePO4 had been improved dramatically by Mn–F co-doping. The initial discharge capacity of LiFe0.99Mn0.01 (PO4)2.99/3F0.01/C samples reached 140.2 mAh/g at 1C rate and only had a small amount of fading in 50 cycles. [ABSTRACT FROM AUTHOR]

Abstract  This paper describes systematic studies on the effect of polyethylene glycol (PEG) molecular weight on the crystal structure and particularly the electrochemical performance of LiV3O8. Scanning electron microscopy results indicate that after the decomposition of PEG, the structure of resultant products exhibits differences in morphology (shape, particle size, and specific surface area). The electrochemical results show that LiV3O8 cathode material treated by PEG (mean molecular weight of 10,000) has greater initial discharge capacity and better cyclic stability than other materials treated with PEG of different molecular weight. Its initial discharge capacity is 282.1 mAh g−1 and maintains 222.2 mAh/g after 50 cycles in 0.5 C rates (150 mA g−1). [ABSTRACT FROM AUTHOR]

Abstract  This paper describes systematic studies on the effect of polyethylene glycol (PEG) molecular weight on the crystal structure and particularly the electrochemical performance of LiV3O8. Scanning electron microscopy results indicate that after the decomposition of PEG, the structure of resultant products exhibits differences in morphology (shape, particle size, and specific surface area). The electrochemical results show that LiV3O8 cathode material treated by PEG (mean molecular weight of 10,000) has greater initial discharge capacity and better cyclic stability than other materials treated with PEG of different molecular weight. Its initial discharge capacity is 282.1 mAh g−1 and maintains 222.2 mAh/g after 50 cycles in 0.5 C rates (150 mA g−1). [ABSTRACT FROM AUTHOR]

Abstract  The olivine-type cathode materials of LiFePO4 were prepared via solid-state reaction under argon atmosphere and doped by chlorine to improve their electrochemical performances. The crystal structure, morphology, and electrochemical properties of the prepared samples were investigated using thermogravimetry–differential scanning calorimetry, X-ray diffraction, Fourier transform infrared, scanning electron microscopy, cyclic voltammetry, and charge–discharge cycle measurements. The result showed that the electrochemical performance of LiFePO4 had been improved by chlorine doping, and the effect of chlorine in lattice was discussed. The heavily doped samples show better electrochemical performance in relative high rates. [ABSTRACT FROM AUTHOR]