A Low-Cost Mechanically Rechargeable Aluminum-Air Cell for Energy Conversion Using Low-Grade Aluminum Foil

The performance of a mechanically rechargeable aluminum (Al)-air cell, fabricated with low-cost materials including low-grade aluminum foil and carbon paper electrodes, was evaluated. The design adopted a free gravity flow for the electrolyte to eliminate the use of an external pump. A tank for storing waste electrolyte was designed with a dedicated channel for the collection of hydrogen gas generated during the cell discharge. The cell achieved a high utilization efficiency of aluminum. Considering both the electricity and hydrogen generated, an overall utilization efficiency of around 90% or even higher could be achieved under different working voltages. Results of repeated recharging/discharging showed that the performances of the cell could be maintained for repeated refilling.