Enhanced Electrochemical Performance of Aluminum-Air Batteries Using Graphite and Graphene Oxide Electrocatalysts Doped with Nitrogen, Sulfur, and Phosphorus

In this study, experiments were performed on aluminum-air batteries to calculate the effect of using different electrocatalysts. N-, S-doped graphite (NSGr), N-, P-doped graphite (NPGr), graphene oxide (GO), N-, S-doped reduced graphene oxide (NSRGO), and N-, P-doped reduced graphene oxide (NPRGO) were synthesized and used with graphite. The novelty lies in the application of six electrocatalysts as cathodes for an aluminum-air battery to study the performance of the battery. Firstly, the discharge potential was investigated using these electrocatalysts as cathodes, aluminum as anodes, and a 3.5% NaCl solution (simulating seawater) as the electrolyte. In the second step, the catalytic activities of these electrocatalysts for the ORR were assessed using CV and LSV. According to the findings, the multilayer, fluffy-like morphology of NPRGO and NSRGO confirms that they have a higher specific surface area than their counterparts. For the NPRGO electrocatalyst in the discharge potential test in an Al-air battery, the initial potential value was 1.423 V, and after 600 s, the potential was reduced to 1.364 V, a decline of 3%. As a result, this sample illustrated the best performance among the six electrocatalysts. In the CV experiment, the NPRGO cathode demonstrated a notable shift toward more positive oxygen reduction potentials. Specifically, the NPRGO electrode exhibited a minimum potential of -0.149 V, indicating enhanced electrochemical activity. According to the findings, the ORR catalytic activities of the cathodes range from higher to lower in the following order: NPRGO, NSRGO, GO, NPGr, NSGr, and Gr.