Multilayer hybrid nanosheet of mesoporous carbon−layered metal oxide as a highly efficient electrocatalyst for Li−O2 batteries

Abstract

An effective methodology to explore highly efficient oxygen electrocatalysts and electrodes for Li−O2 batteries is developed via intimate layer-by-layer hybridization between mesoporous carbon layer and highly anisotropic 2D metal oxide nanosheets. The obtained multilayer hybrid nanosheets of mesoporous carbon−layered MnO2 display outstanding functionalities as oxygen electrocatalysts with low overpotential and as the electrodes of Li−O2 batteries with huge discharge capacity of ˜7000 mAhg−1 at 200 mAg−1 and improved cyclability. The excellent electrocatalyst/electrode bifunctionality of the present material is attributable to enhanced electron transfer kinetics, maximized active sites, promoted electrocatalysis kinetics, and stabilization of unstable Mn3+ species. This multilayer hybrid nanosheet structure is advantageous for facilitating reversible formation/decomposition of discharged product during cycling in Li−O2 batteries via promoted electrolyte−oxygen diffusion. The present study underscores that exfoliated metal oxide nanosheet can be used as an efficient immobilization matrix for synthesizing novel 2D multilayer hybrid nanosheets with synergistically-improved electrocatalyst/electrode functionalities.