Abstract
LiMn0·75Fe0·25PO4/C powders were prepared by a facile hydrothermal and ball-milling method, and then calcined. X-ray diffraction and scanning electron microscopy revealed that the calcination temperature had a strong effect on the structure and morphology of the as-prepared powder, and thus, on the subsequent electrochemical performance of the material. When the calcination temperature was increased from 550 to 700°C, the grain size of LiMn0·75Fe0·25PO4/C increased greatly. The electronic conductivities of the carbon coatings, which were obtained from sucrose and calcined at 550 and 700°C, were investigated. The discharge capacities of LiMn0·75Fe0·25PO4/C decreased with increasing calcination temperature, but electrochemical impedance spectroscopy showed that the charge-transfer resistances of LiMn0·75Fe0·25PO4/C electrodes decreased owing to the increase in the electronic conductivity of the carbon coating. Grain growth played a more important role than the electronic conductivity of the carbon coating in the discharge capacity of the electrode. The powder calcined at 550°C exhibited the best electrochemical performance, with a discharge capacity of 131·9 mAh g−1 at a rate of 0·1 C.
Original language | English |
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Pages (from-to) | 16-21 |
Number of pages | 6 |
Journal | Materials Technology |
Volume | 33 |
Issue number | 1 |
DOIs | |
State | Published - 2 Jan 2018 |
Keywords
- calcination temperature
- cathode material
- electronic conductivity
- Li-ion battery