Exploring electrolyte effects in the upcycling of aluminum beverage cans as functional anodes for air fuel cells

This study explores the feasibility of upcycling aluminum beverage cans as functional anodes in aluminum-air (Al-air) fuel cells, aiming to valorize post-consumer waste for sustainable energy generation. The electrochemical performance of these systems was evaluated using various electrolytes-acidic (sulfuric acid and hydrochloric acid), alkaline (potassium hydroxide and sodium hydroxide), and neutral (sodium chloride)-at different concentrations. Polarization behavior and maximum power density were analyzed to determine optimal electrolyte conditions. Alkaline electrolytes exhibited superior performance, with potassium hydroxide delivering the highest power density of 35.8 W/m² at optimal concentration, followed by sodium hydroxide at 31.6 W/m². In contrast, neutral (NaCl, 6.08 W/m²) and acidic electrolytes (HCl, 6.1 W/m²; H₂SO₄, 3.39 W/m²) demonstrated moderate to low performance. Although theoretical open circuit potentials (OCPs) are higher for acidic electrolytes, experimental values were lower due to increased parasitic reactions and hydrogen evolution, particularly in acidic environments. The study further investigates the impact of temperature, revealing that elevated temperatures significantly enhance power output and reduce activation energy barriers. Apparent activation energies were estimated for each electrolyte, highlighting differences in electrochemical kinetics across systems. Overall, this work not only underscores the critical role of electrolyte nature and temperature on battery performance but also presents a sustainable strategy for repurposing aluminum waste into energy-generating components. Moreover, this approach not only enhances the value of aluminum waste but also offers a scalable pathway for sustainable energy generation through post-consumer material utilization.