Identifying efficient two-dimensional transition metal oxide cathodes for non-aqueous lithium–oxygen batteries using the work function as a simple descriptor†

Abstract

The energy density of a non-aqueous lithium–oxygen battery (LOB) is far below its theoretical value, which is attributable to the slow kinetics of the redox reaction at the cathode. To address this challenge, we employ first-principles calculations to explore the potential application of 356 kinds of two-dimensional transition metal oxides (2D TMOs) as bifunctional oxygen reduction/evolution reaction (ORR/OER) catalysts for non-aqueous LOBs. We introduce the work function (W_F) of 2D TMOs as a key descriptor for the first time, which is instrumental in evaluating the LiO₂ adsorption energy (E_ads) and the overall catalytic properties. This approach facilitates the rapid screening of materials such as 1T-VO₂, W₂O₄, Mo₂O₄, and Re₂O₄, highlighting their excellent activities in ORR/OER catalysis. This work emphasizes the critical role of the W_F in the catalytic ORR/OER on 2D TMOs, which is intended to provide inspiration for the future development of LOBs.