Electrolyte and Cathode Modifications of Rechargeable Micro Aluminum Air Batteries

Student’s name: Rohan Mody Home Institution: Illinois Institute of Technology NNCI Site: MANTH @ University of Pennsylvania REU Principal Investigator: Dr. Sue Ann Bidstrup-Allen - Department of Chemical and Biomolecular Engineering, University of Pennsylvania REU Mentor: Yanghang Huang - Department of Chemical and Biomolecular Engineering, University of Pennsylvania Abstract: Micro Aluminum-Air Batteries (mAABs) operating with aqueous electrolytes have shown promise in extending the flight duration of small-scale quadrotor drones. However, a main constraint of the aqueous electrolyte mAAB is that it cannot be recharged due to the limited stability of the aqueous electrolyte. In this work, we will explore alternate electrolyte solutions, primarily of the organic ionic liquid type, to allow for rechargeability. Combining AlCl3 and EMImCl forms an ionic solution and can be used as an electrolyte, enabling a mAAB to be discharged and charged continuously under 0.1 mA. Altering the ratio of AlCl3 and EMImCl can result in a higher power output due to the increased concentration of the Al2Cl7- ion. In addition, organic ionic liquid electrolytes have decreased corrosion rates of the aluminum anode compared to aqueous solutions, resulting in longer battery shelf life and less degradation in the anodic columbic efficiency. We have also characterized the cathode utilized within mAABs with the help of EDAX. The cathode is fabricated via co-sputtering Ag and Cu, followed by Cu selective etching to increase the surface area of Ag. EDAX is used to quantify the dealloying process, which shows that the cathode has a 9:1 atomic weight percentage ratio between Ag and Cu. Preliminary results suggest the promise of secondary mAABs, and further research is required to determine their application within small-scale quadrotor drones.