Nanostructured intermetallic InSb as a high-capacity and high-performance negative electrode for sodium-ion batteries
Résumé
Following the trends of alloys as negative electrodes for Na-ion batteries, the sodiation of the InSb intermetallic compound was investigated for the first time. The benefit of coupling Sb with In was evaluated through the synthesis of InSb by a chemical reduction in the form of nanostructured particles assembled in micrometric aggregates. After a full structural, morphological and surface characterization, the electrochemical performance of nanostructured InSb was examined in a carbonated electrolyte with fluoroethylene carbonate (FEC) as additive. The performance turns out to be remarkable with a capacity around 450 mAh g-1 after 50 cycles at C/5. In terms of cyclability, the capacity of InSb is impressively stable at 1C with a capacity retention of 96 % up to 100 cycles, in contrast to the strong capacity decay observed for a nanostructured Sb powder produced in a similar fashion. A good high-rate behavior is also observed with a capacity of 310 mAh g-1 at 5C. The better stability of the InSb compound compared to pure Sb suggests that combining In with Sb improves the ability of the material to alleviate volume expansion and mechanical stress during the repeated sodiation/desodiation processes. Surface and structural characterization by X-Ray photoelectron spectroscopy, X-Ray diffraction and electrochemical impedance spectroscopy after cycling were finally implemented to shed light on the SEI composition and electrochemical behavior of the promising InSb compound.
Domaines
Matériaux
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