Graphene Oxide Addition Induces the Improvement of ORR Catalysis Properties of Low-Cost Mn-Based Catalyst Used for Al-Air Battery

To further improve the oxygen reduction reaction (ORR) activity of low-cost Mn based catalyst, graphene oxide (GO) was added in the preparation of one dimensional (1D) α-MnO₂ nanorod using KMnO₄-MnSO₄ system via hydrothermal method. Experimental results showed that the GO addition (20 wt%) could induce the formation of MnO(OH) nanorod. The Mn based@GO catalyst had more surface defects and oxygen vacancies compared with pure α-MnO₂. The onset potential, half-wave potential (E1/2) and limiting current density were significantly enhanced from 0.86 V/0.66 V/3.56 mA cm-2 to 0.91 V/0.77 V/5.41 mA cm-2, indicating that GO addition could greatly improve the catalytic activity of Mn based catalyst. Furthermore, the discharge voltage, power density, mass energy density of Al-air battery using Mn based@GO catalyst were greatly improved comparing with the usage of pure MnO₂ catalyst, and it was also found that the application effect of Mn based @GO catalyst in the Al-air battery was almost comparable to the commercial 20% Pt/C catalyst. Our research revealed for the first time the commercial potential of the novel and low-cost MnO₂/MnO(OH)@GO nanocomposite in the Al-air battery.