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

초록

An effective methodology to explore highly efficient oxygen electrocatalysts and electrodes for Li - O-2 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 - O-2 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 Mn(3+)species. This multilayer hybrid nanosheet structure is advantageous for facilitating reversible formation/decomposition of discharged product during cycling in Li - O-2 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.

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