LiOH Decomposition by NiO/ZrO2 in Li-Air Battery: Chemical Imaging with Operando Synchrotron Diffraction and Correlative Neutron/X-Ray Computed-Tomography Analysis.

Abstract

Li-air batteries attract significant attention due to their highest theoretical energy density among all existing energy storage technologies. Currently, challenges related to extending lifetime and long-term stability limit their practical application. To overcome these issues and enhance the total capacity of Li-air batteries, this study introduces an innovative approach with NiO/ZrO2 catalysts. Operando advanced chemical imaging with micrometer spatial resolution unveils that NiO/ZrO2 catalysts substantially change the kinetics of crystalline lithium hydroxide (LiOH) formation and facilitate its rapid decomposition with heterogeneous distribution. Moreover, ex situ combined neutron and X-ray computed tomography (CT) analysis, provide evidence of distinct lithium phases homogeneously distributed in the presence of NiO/ZrO2. These findings underscore the material's superior physico-chemical and electronic properties, with more efficient oxygen diffusion and indications of lower obstruction to its active sites, avoiding clogging in the active electrode, a common cause of capacity loss. Electrochemical tests conducted at high current density demonstrated a significant kinetic enhancement of the oxygen reduction and evolution reactions, resulting in improved charge and discharge processes with low overpotential. This pioneering approach using NiO/ZrO2 catalysts represents a step toward on developing the full potential of Li-air batteries as high-energy-density energy storage systems.