The main advantage of magnesium batteries is its very large theoretical capacities. Owing to the divalent nature of Mg²⁺ ions, it has substantially higher volumetric and gravimetric capacities. (3833 mAh cm^-3 and 2205mAh g^-1 respectively). Mg batteries does not experience the irreversible capacity loss due to the solid electrolyte interphase (SEI) formation that usually occurs in many battery systems including Li and Na. In addition, Mg has better stability in ambient conditions, hence the battery packaging does not require any inert atmosphere. Mg metal also lacks dendrite formation and associated battery failure due to internal short circuit. The main challenge of Mg battery research is the development of compatible cathode materials. Unlike the Li+ ion, the Mg2+ divalent ion is more electropositive. Since the ionic radii of both the ions is more or less same (Li+ – 0.76 Å, Mg2+ – 0.72 Å) the effective charge density of Mg ion is higher than that of Li. Hence, Mg2+ ions exhibit more effective columbic interaction with the cathode materials. The kinetics of this interaction slows down Mg-ion intercalation to the cathode lattice, resulting in low energy and power density.

In order to overcome the energy and power density limitations of Mg batteries, we have designed and synthesized nanostructured metal oxide cathodes. Mg-ion storage in this case follows a pseudocapacitive mechanism. The diffusion independent nature of pseudocapacitive mechanisms enables the ultrafast charging (high power density) of the Mg battery.