One-Pot Solvothermal Synthesis of Spinel MgFe₂O₄ Nanoparticles as a Promising Cathode Material for Rechargeable Mg-ion Battery

The essence of rechargeable Mg-ion batteries has already been verbalized because of its high specific capacity and large volumetric energy density and hence, a promising alternative to Li-ion batteries. In this study, a facile one-pot solvothermal method has been applied to synthesize the spinel MgFe₂O₄ nanoparticles with an average particle size below 50 nm. The spinel MgFe₂O₄ has been used for the first time as a cathode material for Mg-ion battery. The electrochemical charge–discharge performance has been demonstrated at different C-rate (0.1–2 C). The phase pure spinel structured cathode has revealed a discharge capacity of 52.22 mAh g⁻¹ at 0.1C in the 1st cycle and became stable after 2–3 cycles, and an average specific capacity of 39 mAh g⁻¹ has been recorded after 50 cycles. The average coulombic efficiency of the cell was found to be 88% up to 50 cycles. Furthermore, with increasing C-rate, the specific capacity decreased gradually, followed by the possible phase conversion reaction (spinel to rock-salt and vice versa) of the cathode.