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 trans...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 ℃ and Fe2P2O7 fully reacts with Li2CO3 to form LiFePO4 in the temperature range of 663.4-890 ℃. The primary particles of LiFePO4/C samples prepared at 670, 700 and 750 ℃ respectively exhibit uniform morphology and narrow size distribution, 0.5-3 μm for those obtained at 670 and 700 ℃ and 0.5-5 μm for those obtained at 750 ℃. LiFePO4/C （carbon content of 5.49%, mass fraction） made at 670 ℃ shows an appreciable average capacity of 153.2 mA·h/g at 0.1C in the first 50 cycles.展开更多
A polarographic catalytic wave of cobalt in the substrate solution (pH=8.5) of diacetyldioxime potassium pyrophosphate ammonium chloride was studied and a new method for rapid determination of trace cobalt in complex ...A polarographic catalytic wave of cobalt in the substrate solution (pH=8.5) of diacetyldioxime potassium pyrophosphate ammonium chloride was studied and a new method for rapid determination of trace cobalt in complex zinc electrolyte solution was developed. The results show that there is a very sensitive catalytic wave of cobalt at 1.23 V. At least three hundred thousand fold Zn 2+ does not affect the determination of cobalt. The method is easy to operate and rapid, and when the signal to noise rate equals 2, the detection limit is 6×10 -9 mol·L -1 . A good linear relationship exists between the concentration of cobalt within 0.001 ～3.0 μg·mL -1 and the peak current. The method has successfully been used in the determination of trace cobalt in complex solution of the workshop for electrolyzing zinc.展开更多
基金Project(2010ZC051)supported by the Natural Science Foundation of Yunnan Province,ChinaProject(2009-041)supported by Analysis and Testing Foundation from Kunming University of Science and Technology,ChinaProject(14118245)supported by the Starting Research Fund from Kunming University of Science and Technology,China
文摘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 ℃ and Fe2P2O7 fully reacts with Li2CO3 to form LiFePO4 in the temperature range of 663.4-890 ℃. The primary particles of LiFePO4/C samples prepared at 670, 700 and 750 ℃ respectively exhibit uniform morphology and narrow size distribution, 0.5-3 μm for those obtained at 670 and 700 ℃ and 0.5-5 μm for those obtained at 750 ℃. LiFePO4/C （carbon content of 5.49%, mass fraction） made at 670 ℃ shows an appreciable average capacity of 153.2 mA·h/g at 0.1C in the first 50 cycles.
基金The Science and Research Foundation of Education Commission of Hunan Province!(No.98C118)
文摘A polarographic catalytic wave of cobalt in the substrate solution (pH=8.5) of diacetyldioxime potassium pyrophosphate ammonium chloride was studied and a new method for rapid determination of trace cobalt in complex zinc electrolyte solution was developed. The results show that there is a very sensitive catalytic wave of cobalt at 1.23 V. At least three hundred thousand fold Zn 2+ does not affect the determination of cobalt. The method is easy to operate and rapid, and when the signal to noise rate equals 2, the detection limit is 6×10 -9 mol·L -1 . A good linear relationship exists between the concentration of cobalt within 0.001 ～3.0 μg·mL -1 and the peak current. The method has successfully been used in the determination of trace cobalt in complex solution of the workshop for electrolyzing zinc.
