Behaviour of Zn-MnO2 battery under externally applied magnetic field

Zn-MnO2 batteries offer high theoretical capacity, low cost, safety, and environmental benefits. However, their commercial potential is limited by zinc dendrite formation and manganese dissolution. Typically, these issues are addressed through internal modifications of the cell. In this study, an external magnetic field is applied to induce Lorentz forces on the Zn2+ ions, promoting uniform zinc dissolution and deposition, thereby suppressing dendrite formation. Initially, the morphology evolution of the Zn electrode and the specific discharge capacity of the battery was analysed at different magnetic field strengths. Then the optimum magnetic field strength was used to study the Zn deposition/dissolution and the charge storage behavior at different current densities. UV-Vis spectroscopy and ICP-MS analysis was done to study the electrolyte content during charge/discharge in the presence of the magnetic field. With a 2.91 kG magnetic field, substantial mitigation of dendrite formation and enhanced electrochemical performance was observed, particularly at high charge/discharge rates. Cyclic stability tests showed 83 % capacity retention with the magnetic field after 500 cycles at 1000 mA g- 1, compared to 52.9 % without it. Additionally, manganese dissolution was reduced as Mn2+ ions were retained within the positive electrode under the magnetic field. This approach highlights the potential of magnetic field-assisted ZIBs for fast charging applications and suggests exploring the synergy of combining magnetic fields with internal cell modifications to achieve further improved electrochemical performance.