Maximum catalytic activity of Pt3M in Li-O2 batteries: M=group V transition metals. (September 2016)

• Record Type: Journal Article
• Authors: Kang, Yong-Ju; Jung, Sung Chul; Kim, Hyung-Jin; Han, Young-Kyu; Oh, Si Hyoung
• Is Part Of: Nano energy. Volume 27(2016:Sep.)
• Page Start: 1
• Page End: 7
• Publication Date: 2016-09
• Subjects: Electrocatalyst -- Oxygen reduction reaction -- Oxygen evolution reaction -- Li-O2 battery -- Sluggish kinetics -- First principles calculations; Nanoscience -- Periodicals; Nanotechnology -- Periodicals; Nanostructured materials -- Periodicals; Power resources -- Technological innovations -- Periodicals; Nanoscience; Nanostructured materials; Nanotechnology; Power resources -- Technological innovations; Periodicals; 621.042
• DOI: 10.1016/j.nanoen.2016.06.040
• Languages: English
• ISSNs: 2211-2855

Abstract

Abstract: Li-O2 batteries are considered as promising power sources for electric vehicles due to their remarkably high energy density. However, low rate capability and short cycle life caused by sluggish oxygen reduction/evolution reaction (ORR/OER) kinetics limit their practical applications. Here, we investigate the catalytic activities of Pt3 M bimetallic alloys (M=3 d, 4 d, and 5 d transition metals) for improving the ORR and OER kinetics using first-principles calculations. We found that the group 5 elements (V, Nb, and Ta in 3 d, 4 d, and 5 d periods, respectively) are the most effective alloy components for high catalytic activity. Pt3 V, Pt3 Nb, and Pt3 Ta alloys exhibit considerably lower ORR and OER overpotentials (by 71–77% and 57–59%, respectively) than those of Pt. The catalytic activities are successfully described by the adsorption strengths of reaction intermediate species (Li and LiO2 ) on the alloy surface rather than the d -band center of the alloy surface and are fundamentally controlled by the amount of surface charge. The superior catalytic activities of Pt3 M alloys with the group 5 elements originate from their electron-rich surfaces and can also be interpreted in terms of the integration of mechanical interplay and chemical interplay of Pt and M, i.e., an appropriate trade-off between surface strain and ligand effects. Graphical abstract: Highlights: The group V elements are optimal for maximum catalytic activity of Pt3 M. Adsorption energies of Li and LiO2 are critical descriptors for catalytic activity. The catalytic activity cannot be fully explained by the d -band center theory. Electron-rich Pt-skin surface is essential for achieving high catalytic efficiency. Both surface strain and ligand effect are responsible for the superior activity.