On a new calcium vanadate: synthesis, structure and Li insertion behavior
Abstract
A synthetic form of the mineral hewettite was prepared via a new route in aqueous medium, starting either from the crystalline compound Li 1.1V 3O 8, or from its amorphous precursor. The anhydrous, crystalline derivative Ca 0.5V 3O 8 was obtained by heating the synthetic hewettite at 250°C under dynamic vacuum. The diffraction studies show that the 2D structure of Ca 0.5V 3O 8 involves the same V 3O 8 layers as in the hewettite or in Li 1+ αV 3O 8. The stacking of the layers is similar to that in the metahewettite. A structural model is proposed, where the Ca 2+ ions occupy octahedral sites in the interlayer space. The electrochemical behavior of Ca 0.5V 3O 8 vs. lithium insertion is presented. It is original and reveals particularly good performances in terms of stability during cycling at C/5 rate. The homologues obtained with Mg or Ba, instead of Ca, are briefly presented.
- Publication:
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Journal of Solid State Chemistry France
- Pub Date:
- April 2003
- DOI:
- 10.1016/S0022-4596(02)00164-0
- Bibcode:
- 2003JSSCh.172..116J