Engineering Catalysis at Solid–Solid Interfaces Using Non-Precious Mixed Metal Oxides for Energy Storage in Batteries

Advancing our understanding of solid–solid interfacial electrocatalysis is central toward engineering the next generation energy storage technologies. Li-O₂ batteries provide among the highest energy densities, making them attractive for the widespread electrification of the transportation sector.¹ These systems rely on the reversible redox chemistry between metallic Li and molecular O₂ leading to the formation and dissociation of solid Li_xO₂ species (1 ≤ x ≤ 2). Although promising, these systems suffer from large overpotential losses, consequently resulting in reduced round-trip efficiencies.^{2, 3} Various catalysts have been used to overcome these losses. However, limited understanding between an electrocatalyst surface and the formed solid Li_xO₂ products exists.

In this presentation, well-controlled synthesis, detailed electrochemical and characterization studies, and density functional theory (DFT) calculations are combined to develop a framework for understanding the formation of solid Li_xO₂ products on oxide electrocatalyst surfaces.² Initially, all observations are benchmarked using nanostructured La₂NiO₄ (LNO) as the catalyst. A significant enhancement in the overall performance (>0.7 V) is observed upon the incorporation of (001) NiO terminated LNO. The enhanced performance of LNO stems from its ability to selectively stabilize conductive LiO₂ films during discharge, which oxidizes at lower potentials than conventional Li₂O₂. The developed approach for LNO is extended to various A- and B-site systems to identify the geometric and electronic factors that selectively perturb the film formation energetics for enhanced performance. A rigorous framework for tuning solid–solid interfacial catalysis on these systems is devised; knowledge that is critical for enhancing the efficiency of next generation energy storage technologies.

References

(1) Aurbach, D.; McCloskey, B. D.; Nazar, L. F.; Bruce, P. G., Nat. Energy 2016, 1, 16128.

(2) Samira, S.^†; Deshpande, S.^†; Roberts, C. A.; Greeley, J.; Nikolla, E., Chem. Mater. 2019, 31, 7300-7310.

(3) Samira, S.^†, Gu, X. K.^†, Nikolla, E., ACS Catal. 2019, 9, 10575-10586.