Exploring the intercalation chemistry and Li ion dynamics in Li4WO5: An anode material for Li-ion batteries

Abstract

Electrochemical properties, Li ion dynamics and intercalation chemistry in Li4WO5 bulk material is explored in this work. X-ray diffraction and Raman spectra studies confirm the formation of Li4WO5 in orthorhombic structure. Electrochemical charge discharge studies at 0.1 C rate reveal that the discharge and charge capacity values at 2nd cycle is 364 mAh/g 286 mAh/g respectively. After 100 cycles the discharge and charge capacity values are seen to increase to 575 mAh/g and 549 mAh/g respectively with 99% Columbic efficiency. Intercalation chemistry and retention of orthorhombic structure during the electrochemical cycling with small changes in the lattice parameters in Li4WO5 is confirmed from the ex-situ XRD and Raman studies. In-situ XRD measurement during the first cycle confirms the stable structure of Li4WO5 with a small distortion in (531) plane due to the removal and insertion of Li. Irreversible redox peak and the unknown phases from the solid electrolyte interface appeared at 0.7 V during the first discharge process are probed from the addition diffraction peaks appeared in the in-situ XRD pattern. The Li ion diffusion coefficient value is calculated to be 2.96 × 10−14 cm2/s. Electrochemical impedance spectroscopy (EIS) studies showed the reduction in charge transfer resistance with increasing cycle number. Observed intercalation chemistry, high-rate performance and virtuous specific capacity in Li4WO5 indicates that it can be applied as an anode material for high performance LIB’s.