The solid-state reaction facilitated by a microwave-assisted method for lithium vanadium silicon oxide synthesis by incorporating pure silica and rice husk ash for the application as anode material in lithium-ion battery

Abstract

A solid-state reaction: heated by the microwave-assisted method was used for the synthesis of Li3.6Si0.6V0.4O4 using LiNO3, V2O4, and (pure silica/silica from rice husk ash). In this work, the influence of the source of silica, and microwave heating time was studied on the electrochemical properties formation of the product. and electrochemical properties were measured by cyclic voltammetry. The substances were ground and heated with a microwave oven at 400 and 600 W for 5 min. Among the compound prepared from both pure silica and silica from rice husk ash with 600 W microwave heating provided the highest specific capacitance for both silica source supercapacitors at 444–616 F g−1 at the rate of scanning 5 mV s−1. Furthermore, the product from both silica heated with 600 W of microwave show a retention capacity of 88.8% after 300 cycles at a charge-discharge rate in the range of 0.1–5 C between 1 and 2.5 V. The result shows the specific capacity was 221 mAh.g−1, at 1 C discharge rate. To identify the empirical formula of the compound, X-ray diffraction and transmission electron microscopy were employed which suggested that the empirical formula was Li3.6Si0.6V0.4O4. The Fourier transform infrared and resonance Raman spectroscopy exhibited the bonds of Si–O, Li–O, VO, and Si–O–Si. The oxidation states of V for Li3.6Si0.6V0.4O4 and Li3VO4 in the products were verified to be V4+ and V5+ by X-Ray absorption near the edge structure. Scanning electron microscopy was employed for the porosity and crystal size of the product from rice husk ash precursor has a higher porosity and small crystal size than pure SiO2 precursor. These results suggested the Li3.6Si0.6V0.4O4 would be potential an anode in the lithium-ion battery.