Tailoring α-MnO2 gas diffusion electrodes for enhanced oxygen reduction in aluminum-air batteries
Rampf A, Leiter R, Fleischmann S, Elia GA, Zeis R (2026)
Publication Type: Journal article
Publication year: 2026
Journal
Book Volume: 114
Pages Range: 473-484
DOI: 10.1016/j.jechem.2025.10.028
Abstract
α-MnO2 is a promising, inexpensive, and readily producible catalyst for the oxygen reduction reaction (ORR) in alkaline media, but its application is limited by low electronic conductivity. In this study, we enhance the performance of α-MnO2 electrodes by systematically varying the α-MnO2-to-Vulcan ratio within the catalyst layer. Electrodes are evaluated in a gas diffusion electrode (GDE) half-cell, where an optimized catalyst layer composition leads to significantly improved ORR performance. By fine-tuning both the α-MnO2-to-Vulcan ratio and the α-MnO2 loading, the electrode outperforms a commercial MnO2-based electrode and approaches the performance of the Pt/C benchmark. The improvement is attributed to the presence of a three-dimensional (3D) Vulcan network electronically connecting catalytically active α-MnO2 sites with the substrate. Additionally, the optimized electrodes are employed in a prototype Al-O2 flow cell. Under constant oxygen flow, power densities exceed 250 mW cm−2, which is significantly higher than that of conventional Al-air batteries. Electrochemical impedance spectroscopy combined with distribution of relaxation times (DRT) analysis enables the separation of anode and cathode charge transfer impedances without the need for an additional reference electrode. The analysis reveals that the anode contributes more than twice as much impedance as the cathode, highlighting the need for further anode optimization. This work demonstrates a transferable approach for catalyst layer screening under technically relevant conditions in the GDE half-cell. Subsequent measurements in an Al-O2 flow cell validate the approach. The methodology is widely applicable to the development of advanced electrodes for a variety of metal-air battery technologies.
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APA:
Rampf, A., Leiter, R., Fleischmann, S., Elia, G.A., & Zeis, R. (2026). Tailoring α-MnO2 gas diffusion electrodes for enhanced oxygen reduction in aluminum-air batteries. Journal of Energy Chemistry, 114, 473-484. https://doi.org/10.1016/j.jechem.2025.10.028
MLA:
Rampf, Alexander, et al. "Tailoring α-MnO2 gas diffusion electrodes for enhanced oxygen reduction in aluminum-air batteries." Journal of Energy Chemistry 114 (2026): 473-484.
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