Investigating electrocatalytic properties of β12-borophene as a cathode material for an efficient lithium-oxygen battery: a first-principles study

Abstract

Responding to the pressing need to mitigate climate change effects due to fossil fuel consumption, there is a collective push to transition towards renewable and clean energy sources. However, the effectiveness of this move depends on an efficient energy storage system that surpasses current lithium-ion battery technology. The lithium-oxygen battery, having significantly high theoretical specific capacity compared to other systems, has emerged as a promising solution. However, the issues of poor cathode electrode conductivity and slow kinetics during discharge product formation have limited its practical applications. In this work, the first principles-based density functional theory was used to investigate the electrocatalytic properties of β₁₂-borophene as a cathode electrode material for a high-performance lithium-oxygen battery. The adsorption energy, charge density distributions, Gibbs free energy changes, and diffusion energy barriers of lithium superoxide (LiO₂) on β₁₂-borophene were calculated. Our findings revealed several important insights: The adsorption energy was found to be − 3.70 eV, suggesting a strong tendency for the LiO₂ to remain anchored to the material during the discharging process. The dynamics in the charge density distributions between LiO₂ and the β₁₂-borophene substrate exhibited complex behavior. The analysis of the Gibbs free energy changes of the reactions yielded an overpotential of − 1.87 V, this moderate value suggests spontaneous reactions during the formation of the discharge products. Most interestingly, the density of states and band structure analysis suggested the preservation of metallic properties and improved electrical conductivity of the material after the adsorption of LiO₂. Additionally, β₁₂-borophene has a relatively low diffusion energy barrier of 1.08 eV, implying effortless diffusion of the LiO₂ and an increase in the rate of discharging process. Ultimately, the predicted electronic properties of β₁₂-borophene, make it a strong candidate as a cathode electrode material for an efficient lithium-oxygen battery.