Enhancing Electrochemical Performance of Aluminum-Oxygen Batteries with Graphene Aerogel Cathode

Aluminum-oxygen batteries (AOBs) own the benefits of high energy density (8.14 kWh kg^-1), low cost, and high safety. However, the design of a cathode with high surface area, structure integrity, and good catalytic performance is still challenging for rechargeable AOBs. Herein, the fabrication of a robust self-supporting cathode using 3D graphene aerogel (3DGA) for rechargeable AOBs is demonstrated. Electroanalysis showed that the 3DGA presented good catalytic activity in both oxygen reduction and evolution reactions, which allowed the AOB to operate for >90 cycles with low overpotentials at a current density of 0.2 mA cm^-2, and a high Coulombic efficiency of ca. 99% using ionic liquid as electrolyte. In comparison, the cell with the carbon paper cathode can only cycle for 50 rounds. The excellent cyclic performance can be attributed to the porous structure, large surface area, good electric conductivity, and catalytic activity of the 3DGA, which is prospective to be applied for other metal-air batteries, fuel cells, and supercapacitors.