Tuning Li2O2 Formation Routes by Facet Engineering of MnO2 Cathode Catalysts
Document Type
Article
Publication Date
7-23-2019
Department
Department of Mechanical Engineering-Engineering Mechanics
Abstract
In lithium–oxygen batteries, the solubility of LiO2 intermediates in the electrolyte regulates the formation routes of the Li2O2 discharge product. High-donor-number electrolytes with a high solubility of LiO2 tend to promote the formation of Li2O2 large particles following the solution route, which eventually benefits the cell capacity and cycle life. Here, we propose that facet engineering of cathode catalysts could be another direction in tuning the formation routes of Li2O2. In this work, β-MnO2 crystals with high occupancies of {111} or {100} facets were adopted as cathode catalysts in Li–O2 batteries with a tetra(ethylene)glycol dimethyl ether electrolyte. The {111}-dominated β-MnO2 catalyzed the formation of the Li2O2 discharge product into large toroids following the solution routes, while {100}-dominated β-MnO2 facilitated the formation of Li2O2 thin films through the surface routes. Further computational studies indicate that the different formation routes of Li2O2 could be related to different adsorption energies of LiO2 on the two facets of β-MnO2. Our results demonstrate that facet engineering of cathode catalysts could be a new way to tune the formation route of Li2O2 in a low-donor-number electrolyte. We anticipate that this new finding would offer more choices for the design of lithium–oxygen batteries with high capacities and ultimately a long cycle life.
Publication Title
Journal of the American Chemical Society
Recommended Citation
Yao, W.,
Yuan, Y.,
Tan, G.,
Liu, C.,
Cheng, M.,
Yurkiv, V.,
Bi, X.,
Long, F.,
Friedrich, C.,
Shahbazian-Yassar, R.,
&
et al.
(2019).
Tuning Li2O2 Formation Routes by Facet Engineering of MnO2 Cathode Catalysts.
Journal of the American Chemical Society,
141(32), 12832-12838.
http://doi.org/10.1021/jacs.9b05992
Retrieved from: https://digitalcommons.mtu.edu/michigantech-p/767
Publisher's Statement
Copyright © 2019 American Chemical Society. Publisher’s version of record: https://doi.org/10.1021/jacs.9b05992