Aluminium-air batteries have received increased interest for niche applications requiring an expendable, light-weight high power density battery such as those required in a micro-unmanned aerial vehicle.
The classical aluminium-air cell retains niche applications and continues to attract attention due to its simple, safe and robust design which is environmentally sustainable.
With a predicted cell voltage of 2.75 V comprising the oxidation of aluminium to aluminate ions and the reduction of oxygen is an ideal candidate for micro air vehicles (MAVs). Many challenges still remain including: a) aluminium alloy anode structure, b) efficient air cathodes, c) reaction environment, d) current and potential distribution, e) operating and design parameters, f) structural batteries.
The project adopts an electrochemical engineering approach using DC electrochemical techniques. Anode structures are focus on layered, porous, 3-D materials to achieve a high surface area with low density and acceptable electrical conductivity.
The time-dependence of cell voltage is monitored as a function of operational variables such as electrode material, cell geometry and current density using an intelligent load to control the discharge rate. Cell voltage components and power output are also measured as a function of current density for fixed volume electrode structures.
Cell geometry effects are scrutinised by giving attention to features such as the inter-electrode gap, electrode conductivity, electrode shape factors and porosity and cell body-electrode geometry. Flow effects are quantified using natural convection and pumped electrolyte flow, including use of novel microchannels.
Current distribution over porous electrode surfaces will be monitored in a 2-D plane, using segmented electrode structures while the potential distribution mapped across the electrode surface using moving Luggin probe and shaped electrode techniques.