Tailoring the adsorption behavior of superoxide intermediates on nickel carbide enables high-rate Li–O2 batteries

Abstract

Probing the relationship between the adsorption of superoxide species and the kinetics of Li–O2 chemistry is critical for designing superior oxygen electrodes for the Li–O2 battery, yet the modulation essence, especially at the atomic level, remains little understood. Herein, we reveal that the adsorption behaviors of superoxide species can be effectively regulated via a core-induced interfacial charge interaction, and we find that moderate adsorption strength can enable superior rate capability in a Li–O2 battery. More importantly, operando X-ray absorption near-edge structure and surface-enhanced Raman spectroscopy provide tools to monitor in situ the evolution of the superoxide intermediates and the electronic states of the catalyst's metal sites during the discharge and charge processes, and correlate these with the surface adsorption states. The concept of tuning adsorption behavior through interfacial charge engineering could open up new opportunities to further advance the development of the Li–O2 battery and beyond.