The effect of competition between solvation and cathode surface adsorption on the kinetics of lithium−oxygen batteries: A model study based on nanoarray electrodes

Résumé fourni par la source

The donor number (DN) of electrolyte solvents was reported to be the key factor determining LiO 2 intermediate solvation and lithium−oxygen battery (LOB) kinetics. In low-DN solvents, LiO 2 tends to adsorb onto cathode surfaces and undergoes surface-mediated reduction to Li 2 O 2 , while in high-DN solvents, LiO 2 is preferentially solvated and subsequently disproportionates to Li 2 O 2 . However, prior studies overlooked a critical issue: whether cathode surfaces can provide sufficiently strong adsorption for LiO 2 , particularly in low-DN solvents. Herein, this study proposes MnO 2 , NiO, and Co 3 O 4 nanoarray models alongside carbon nanotubes to simultaneously investigate LiO 2 adsorption on different cathodes and solvent DN effects under consistent cathode architectures. Experimental and theoretical analyses reveal that the discharge of oxygen cathodes involves a competition between the solvation of LiO 2 intermediates and their adsorption on cathodes. When an oxygen cathode has strong adsorption of LiO 2 , the adsorption and solvation compete with each other, leading to a solution mechanism in high-DN solvents and a surface mechanism in low-DN solvents. Conversely, if an oxygen cathode shows weak adsorption of LiO 2 , a solution mechanism predominately occurs, regardless of whether in high- or low-DN solvents. Thus, when evaluating solvent effects on LOB kinetics, the adsorption capacity of cathode materials must be fully considered.

Ce résumé expose les affirmations des auteurs. BNTIC ne l’interprète pas comme une validation indépendante des résultats.