Abstract
Synthesis and structural characterization of the first LiFeO2 compound with tetrahedrally coordinated Fe3+ is reported. When used as a positive intercalation electrode in a lithium cell, it can store charge of up to 120 mAhg(-1) at a rate of 100 mAg(-1). However, it converts to the defect spinel LiFe5O8 on cycling. By combining results from powder X-ray diffraction, differential electrochemical mass spectrometry, electrochemical cycling, and TG-MS, it is shown that such conversion, which involved oxygen loss, is not associated with direct O-2 gas evolution but instead reaction with the electrolyte. We suggest that intercalation/ deintercalation is accompanied by the exchange of Li+ by H+ in the material and subsequent loss of H2O, thus converting LiFeO2 to the defect spinel LiFe5O8 on cycling.
Original language | English |
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Pages (from-to) | 3554-3559 |
Number of pages | 6 |
Journal | Journal of the American Chemical Society |
Volume | 130 |
DOIs | |
Publication status | Published - 19 Mar 2008 |
Keywords
- ION BATTERIES
- ELECTROCHEMICAL PROPERTIES
- SECONDARY BATTERIES
- MANGANESE-OXIDE
- IRON-OXIDES
- LI
- ELECTROLYTE
- PERFORMANCE
- PHOSPHATES
- MECHANISM