Electrochemical Li insertion studies on WNb12O33—A shear ReO3 type structure

Electrochemical lithium insertion studies on WNb12O33 synthesized by solid state reaction (SSR) are carried out in the voltage range 1.0–3.2 V. During first discharge 15.6 Li are inserted with a specific capacity of 221 mAh/g. WNb12O33 is also synthesized by sol–gel (SG) technique with a view to enhance the rate capability and cycling properties. The SSR and SG samples are characterized by powder X-ray diffraction (XRD), scanning electron microscopy (SEM) and galvanostatic cycling. Electrochemical cycling performance of SG samples is superior to that of the SSR sample at high ‘C’ rates. The sample synthesized by SG method exhibits high specific capacity of 142 mAh/g after 20 cycles at 20C rate.

The projected structure can be described as 3×4×∞ ReO3 type blocks of NbO6 octahedra sharing corners, joined with identical blocks via tetrahedrally coordinated tungsten atoms.Figure optionsDownload as PowerPoint slide