(334e) Lowering the Charge Overpotentials in Li-O2 Battery By Tailoring the Oxygen Reduction and Evolution Reaction Energetics Using Non-Precious Metal Oxide Electrocatalysts
AIChE Annual Meeting
2018
2018 AIChE Annual Meeting
Catalysis and Reaction Engineering Division
Electrocatalysis and Photoelectrocatalysis V: Oxygen Evolution Reaction
Tuesday, October 30, 2018 - 1:50pm to 2:10pm
Lithium-oxygen (Li-O2) batteries are considered as the next generation energy storage technology with vast potential to contribute to electrification of the transportation sector. Although these systems are promising, several factors have resulted in performance far below the theoretical potential, including sluggish oxygen evolution reaction (OER) kinetics leading to high overpotential losses during charging.1 We report a decrease in these overpotential losses achieved by perturbing the energetics associated with oxygen reduction reaction (ORR) and OER in aprotic Li-O2 cathodes containing non-stoichiometric mixed metal oxide electrocatalysts with mixed electronic and ionic conducting properties.2-3 A combination of well controlled synthesis, electrochemical studies and detailed characterization by Raman spectroscopy, titration, and differential electrochemical mass spectrometry show that these non-stoichiometric mixed metal oxide nanostructures change the energetics associated with ORR as compared to carbon-only electrodes by stabilizing Li-deficient intermediate species (> 50% more LiO2 is detected in the presence of the catalyst), which consequently leads to lower OER overpotentials during charge. In addition, the presence of the catalyst also reduces the charge overpotential losses by lowering the potential required to dissociate Li2O2 during charge. These insights are key in providing new avenues for improving the efficiency of Li-O2 batteries via tailoring the ORR/OER energetics using well-defined nanostructured, non-precious metal oxide electrocatalysts.
References:
(1) Lu, J.; Li, L.; Park, J. B.; Sun, Y. K.; Wu, F.; Amine, K., Aprotic and Aqueous Li-O2 Batteries. Chem. Rev. 2014, 114, 5611-5640.
(2) Gu, X.-K.; Samira, S.; Nikolla, E., Oxygen Sponges for Electrocatalysis: Oxygen Reduction/Evolution on Non-stoichiometric, Mixed Metal Oxides. Chem. Mater. 2018, DOI:10.1021/acs.chemmater.8b00694.
(3) Nacy, A.; Ma, X. F.; Nikolla, E., Nanostructured Nickelate Oxides as Efficient and Stable Cathode Electrocatalysts for Li-O-2 Batteries. Top. Catal. 2015, 58, 513-521.