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Title: Effect of the synthesis conditions on the electrochemical properties of LiFePO{sub 4} obtained from NH{sub 4}FePO{sub 4}

Graphical abstract: - Highlights: • Four different samples of FAP were synthesized by precipitation techniques. • The samples were used as precursors to synthesize electrochemical active LiFePO{sub 4}. • Their morphology, composition, structure and electrochemical performance were studied. • The LiFePO{sub 4} electrochemical performance resulted affected by the preparation method - Abstract: In this paper the morphological, structural and electrochemical properties of crystalline lithium iron phosphate (LiFePO{sub 4}) obtained from ferrous ammonium phosphate (FAP) have been studied. The FAP was obtained following four different processes, namely: (1) homogeneous phase precipitation, (2) heterogeneous phase precipitation from stoichiometric sodium phosphate, (3) heterogeneous phase precipitation from stoichiometric ammonium phosphate, and (4) heterogeneous phase precipitation from over stoichiometric ammonium phosphate. Lithium iron phosphate was prepared by solid state reaction of FAP with lithium hydroxide. In order to evaluate the effect of reaction time and synthesis temperature the LiFePO{sub 4} was prepared varying the heating temperatures (550, 600 and 700 °C) and the reaction times (1 or 2 h). The morphology of the materials was evaluated by scanning electron microscopy while the chemical composition was determined by electron energy loss spectroscopy. X-ray diffraction was used to evaluate phase composition, crystal structure and crystallite size. Themore » so obtained LiFePO{sub 4}'s were fully electrochemical characterized and a correlation was found between the crystal size and the electrochemical performance.« less
Authors:
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Publication Date:
OSTI Identifier:
22341786
Resource Type:
Journal Article
Resource Relation:
Journal Name: Materials Research Bulletin; Journal Volume: 48; Journal Issue: 9; Other Information: Copyright (c) 2013 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved.; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; 37 INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY; AMMONIUM PHOSPHATES; CHEMICAL COMPOSITION; CRYSTAL STRUCTURE; CRYSTALS; IRON PHOSPHATES; PRECIPITATION; SCANNING ELECTRON MICROSCOPY; SOL-GEL PROCESS; SOLIDS; SYNTHESIS; THERMAL GRAVIMETRIC ANALYSIS; X-RAY DIFFRACTION