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Electrochemical lithium insertion behavior of FeNbO4: Structural relations and in situ conversion into FeNb2O6 during carbon coating
- Source :
- Materials Chemistry and Physics. 145:425-433
- Publication Year :
- 2014
- Publisher :
- Elsevier BV, 2014.
-
Abstract
- Electrochemical properties of FeNbO 4 as a lithium insertion anode material were studied with a view to understand structure–property relationships. Orthorhombic and monoclinic polymorphs of FeNbO 4 were synthesized and characterized by powder X-ray diffraction and laser Raman spectroscopy. Possible redox reactions, as deciphered from cyclic voltammograms, suggest the structural similarity between orthorhombic and monoclinic polymorphs upon lithium insertion. A coating of carbon led to a remarkable improvement in the electrochemical performance of monoclinic FeNbO 4 . The coated material exhibited an average reversible capacity of 125.5 mAh g −1 . The material also sustained hundreds of charge/discharge cycles and exhibited good rate capability. Upon coating with carbon, the monoclinic FeNbO 4 transformed into FeNb 2 O 6 . The conversion and stability were confirmed by powder XRD and laser Raman studies of carbon-coated material before and after 450 cycles. The in situ conversion of FeNbO 4 into FeNb 2 O 6 during carbon coating was further supported by EPR studies in which the absence of signal for the carbon-coated material indicated conversion of Fe 3+ to Fe 2+ . Our study reveals the possibility of exploring potential materials in the Fe–Nb–O system and enhancing their performance as anode materials for lithium-ion batteries.
- Subjects :
- Materials science
chemistry.chemical_element
Crystal structure
engineering.material
Condensed Matter Physics
Electrochemistry
Anode
Crystallography
chemistry
Coating
Chemical engineering
engineering
General Materials Science
Orthorhombic crystal system
Lithium
Powder diffraction
Monoclinic crystal system
Subjects
Details
- ISSN :
- 02540584
- Volume :
- 145
- Database :
- OpenAIRE
- Journal :
- Materials Chemistry and Physics
- Accession number :
- edsair.doi...........a038066a46365ba0b1534ae4d5f3fd21