Pyroxene LiVSi2O6 as an electrode material for Li-ion batteries

Lithium vanadium metasilicate (LiVSi2O6) with pyroxene structure has been exploited as an electrode material for Li-ion batteries. Galvanostatic charge and discharge tests show that LiVSi2O6 is able to deliver a capacity of 85 mAh g−1 at 30 °C, and a high capacity of 181 mAh g−1 at 60 °C. The high capacity is believed to be due to the reactions of V3+/V4+ and V2+/V3+redox couples, accompanied by the excess 0.42 Li+ insertion into the lattice forming a Li-rich phase Li1.42VSi2O6. High-energy synchrotron XRD combined with the Rietveld refinement analysis confirms that the electrochemical delithiation–lithiation reaction proceeds by a single phase redox mechanism with an overall volume variation of 1.9% between LiVSi2O6 and its delithiated state, indicating a very stable framework of LiVSi2O6 for Li+ ions extraction–insertion.