Zirconium-doped vanadium oxide and ammonium linked layered cathode to construct a full-cell magnesium-ion battery: a realization and structural, electrochemical study

More than three times higher bulk density, easy to handle in air, and high abundance on earth crust make magnesium metal a desirable element in battery application. Several efforts have been attempted to construct the rechargeable magnesium-ion battery, unfortunately none of them are successful to a limit. Here, a new generation of vanadium oxide linked with ammonium ions is considered an active cathode for magnesium ion insertion. The Zr doped-NH₄V₄O₁₀ (Zr-NVO) nanorod exhibits an initial discharge capacity of 328 mAh g⁻¹ at 40 mA g⁻¹ current density with negligible capacity fading till 150 cycles. The estimated Mg²⁺ diffusivity in such cathode is found to be in the range of 10⁻¹¹ to 10⁻¹² cm² s⁻¹, demonstrating a pronounced Mg-ion mobility in Zr-NVO cathode. In addition, a detailed mechanistic study is performed at different states of charge using XRD, XPS and in-situ XANES analysis. In conclusion, to achieve the ultimate goal of such study, a full-cell is assembled and evaluated by coupling tin anode with magnesiated Zr-NVO cathode. The cell has been cycled for a limited number of cycles and the reason behind the limited cycling behaviour is discussed and offers us a pathway to a resolution of the problem for rechargeable magnesium-ion battery development in the near future.