Impact of magnesium substitution in nickel ferrite: Optical and electrochemical studies

Magnesium doped Ni ferrite nanoparticle (Ni_1-xMg_xFe₂O₄₎ has been synthesized by sol-gel combustion method and it has been analyzed using XRD, UV, FTIR and electrochemical charge-discharge studies. The observed XRD result confirms the nanostructure and it ranges from 23 to 28 nm. Furthermore, band gap energy values and functional group elements have been observed by UV and FTIR, respectively. The lattice constant values varies slightly with respect to magnesium concentration. The band gap energy values increase at the calcination temperature of 500 °C as 0.85, 1.15, 1.2, and 1.45 eV and it decreases when it was calcined at 900 °C as 1.3, 1.25, 1.15, 1.1 eV for x = 0.25, 0.5, 0.75, 1, respectively. The voltage profiles of Ni_1-xMg_xFe₂O₄ nanoparticle electrodes show the discharge and charge capacities of 1021 and 718 mAh/g at 500 °C and 1099 and 747 mAh/g at 900 °C, respectively. The high reversible capacities for the Mg doped Ni ferrite nanoparticle electrodes are confirmed as anode materials for Li ion batteries.