Control of the LiFePO4 electrochemical properties using low-cost iron precursor in a melt process
- 408 Downloads
LiFePO4 was prepared from low-cost iron ore concentrate (containing 4.48 wt.% SiO2 and MgO, CaO and Al2O3 below 0.5 wt.% as contaminant) using a melt synthesis. X-ray diffraction (XRD) refinement associated with Mössbauer spectroscopy and scanning electron microscopy-energy dispersive spectroscopy (SEM-EDX) analyses are used to track the location of Si in the material. It is shown that the iron content in the melt can be used as a means to control the doping rate of elements from iron ore concentrate (IOC) precursor according to the formula (Li1 − z A z )(Fe1 − y M y )(P1 − x Si x )O4. Electrochemical behavior of the material is affected by the doping of LiFePO4. While capacity is decreased in doped material, the cycling stability is much improved. When dopants are out of LiFePO4 structure, capacity retention dramatically drops as well as capacity due to the gravimetric impact of impurity phases. A trade-off between high capacity and best cycling performance is necessary. For instance, slight lack of iron in the melt (6 % deficiency) leads to a capacity only 2 % lower than that of pure Fe2O3-based material for the same stoichiometry and fairly good capacity retention.
KeywordsLiFePO4 Melt synthesis Iron ore concentrate Compositions Impurities
The authors would like to thank NSERC and CFI, through the Automotive Partnership Canada program, and Johnson-Matthey Inc. for their financial support.
- 13.Armand, M, Gauhtier, M, Magnan, JF, and Ravet, N 2002 Method for synthesis of carbon-coated redox materials with controlled size. WO 02/27823 A1Google Scholar
- 22.Talebi-Esfandarani M, Savadogo O (2014) Effects of palladium doping on the structure and electrochemical properties of LiFePO4/C prepared using the sol-gel method. J New Mater Electrochem Syst 17(2):91–97Google Scholar
- 26.Gauthier L, Gauthier M, Lavoie D, Michot C, Ravet N (2003) Process for preparing electroactive insertion compounds and electrode materials obtained therefrom in US Patent 7,534,408 B2Google Scholar
- 31.Nishijima, M, Ootani, T, Kamimura, Y, Sueki, T, Esaki, S, Murai, S, Fujita, K, Tanaka, K, Ohira, K, Koyama, Y, and Tanaka, I (2014) Accelerated discovery of cathode materials with prolonged cycle life for lithium-ion battery. Nat Commun 5Google Scholar
- 33.Brand, R 2008 WinNormos Software, Universität Duisburg-Essen, G. Duisbourg, EditorGoogle Scholar
- 37.Hamelet S, Gibot P, Casas-Cabanas M, Bonnin D, Grey CP, Cabana J, Leriche J-B, Rodriguez-Carvajal J, Courty M, Levasseur S, Carlach P, Van Thournout M, Tarascon J-M, Masquelier C (2009) The effects of moderate thermal treatments under air on LiFePO4-based nano powders. J Mater Chem 19(23):3979–3991CrossRefGoogle Scholar