Mechanically rechargeable zinc-air battery for off-grid and remote power applications

Non-availability of grid-electricity in remote and rural areas presents a challenge for recharging secondary batteries. Mechanically rechargeable zinc-air batteries should mitigate this problem. This work reports a compact, mechanically rechargeable zinc-air battery built around the framework of an electroformed planar nickel mesh current collector. The battery performance was evaluated in longevity and polarization studies. Design and production of the planar, compact battery chassis was done using CAD and 3D printing. A zinc plate and 4-molar KOH were used for the anode and electrolyte respectively. The cathode is an air-breathing gas diffusion electrode that is pressed into the openings of the nickel mesh current collector. The battery electrodes each have a surface area of 400 mm² while the OCV was 1.32 V. From the polarization studies, at a voltage of 1.0 V, a load of 710 Ω (or higher) can be imposed on the cell with the voltage remaining stable. The longevity test also shows that whilst powering a mini-DC motor for 6 hours, the polarisation potential depreciated only minimally.