Synthesis and characterization of LiCo sub(1/3)Mn sub(1/3)Fe sub(1/3)PO sub(4)/C nanocomposite cathode of lithium batteries with high rate performance

• Published in: Journal of power sources 2013-11, Vol.242, p.627-630
• Main Authors: Akimoto, S, Taniguchi, I
• Format: Article
• Language: English
• ISSN: 0378-7753

Olivine structured LiCo sub(1/3)Mn sub(1/3)Fe sub(1/3)PO sub(4)/C nanocomposites were prepared by a combination of spray pyrolysis at 300 degree C and wet ball-milling followed by heat treatment at 500 degree C for 4 h in a 3%H sub(2) + N sub(2) atmosphere. The formation of a solid solution between LiCoPO sub(4), LiMnPO sub(4), and LiFePO sub(4) at this composition was confirmed by X-ray diffraction analysis. Scanning electron microscopy and transmission electron microscopy with equipped energy dispersive spectroscopy verified that the LiCo sub(1/3)Mn sub(1/3)Fe sub(1/3)PO sub(4)/C nanocomposites were agglomerates of LiCo sub(1/3)Mn sub(1/3)Fe sub(1/3)PO sub(4) primary particles with a geometric mean diameter of 107 nm and a uniform chemical composition, and carbon was well distributed on the surface of the agglomerates. The LiCo sub(1/3)Mn sub(1/3)Fe sub(1/3)PO sub(4)/C nanocomposite cathode exhibited a high discharge capacity of 159 mAh g super(-1) at 0.05 C in the potential range of 2.0-5.0 V, corresponding to 94% of theoretical capacity. The capacity retention was 87% after 50 cycles at a charge-discharge rate of 1 C. Furthermore, the rate capability test showed that the high capacity still was retained even at 5 C and 20 C rate with 106 and 72 mAh g super(-1), respectively.