A novel synthesis of LiFePO4/C from Fe2O3 without extra carbon or carbon-containing reductant
来源期刊：中南大学学报(英文版)2014年第6期
论文作者：肖政伟 HU Guo-rong(胡国荣)
文章页码：2143 - 2149
Key words：lithium ion phosphate; ferric oxide; ferrous pyrophosphate; lithium ion cells
Abstract: A novel synthesis of LiFePO4/C from Fe2O3 with no extra carbon or carbon-containing reductant was introduced: Fe2O3 (+NH4H2PO4)→Fe2P2O7(+Li2CO3+glucose)→LiFePO4/C. X-ray diffractometry (XRD), Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM) were utilized to characterize relevant products obtained in the synthetic procedure. The reaction of Fe2P2O7 and Li2CO3 was investigated by thermo-gravimetric and differential thermal analysis (TGA-DTA). Fe2O3 is completely reduced to Fe2P2O7 by NH4H2PO4 at 700 °C and Fe2P2O7 fully reacts with Li2CO3 to form LiFePO4 in the temperature range of 663.4-890 °C. The primary particles of LiFePO4/C samples prepared at 670, 700 and 750 °C respectively exhibit uniform morphology and narrow size distribution, 0.5-3 μm for those obtained at 670 and 700 °C and 0.5-5 μm for those obtained at 750 °C. LiFePO4/C (carbon content of 5.49%, mass fraction) made at 670 °C shows an appreciable average capacity of 153.2 mA·h/g at 0.1C in the first 50 cycles.
XIAO Zheng-wei(肖政伟)1, HU Guo-rong(胡国荣)2
(1. Faculty of Metallurgical and Energy Engineering, Kunming University of Science and Technology,
Kunming 650093, China;
2. School of Metallurgy and Environment, Central South University, Changsha 410083, China)
Abstract:A novel synthesis of LiFePO4/C from Fe2O3 with no extra carbon or carbon-containing reductant was introduced: Fe2O3 (+NH4H2PO4)→Fe2P2O7(+Li2CO3+glucose)→LiFePO4/C. X-ray diffractometry (XRD), Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM) were utilized to characterize relevant products obtained in the synthetic procedure. The reaction of Fe2P2O7 and Li2CO3 was investigated by thermo-gravimetric and differential thermal analysis (TGA-DTA). Fe2O3 is completely reduced to Fe2P2O7 by NH4H2PO4 at 700 °C and Fe2P2O7 fully reacts with Li2CO3 to form LiFePO4 in the temperature range of 663.4-890 °C. The primary particles of LiFePO4/C samples prepared at 670, 700 and 750 °C respectively exhibit uniform morphology and narrow size distribution, 0.5-3 μm for those obtained at 670 and 700 °C and 0.5-5 μm for those obtained at 750 °C. LiFePO4/C (carbon content of 5.49%, mass fraction) made at 670 °C shows an appreciable average capacity of 153.2 mA·h/g at 0.1C in the first 50 cycles.
Key words:lithium ion phosphate; ferric oxide; ferrous pyrophosphate; lithium ion cells
