Electron delocalization and gradient orbital hybridization to enhance charge kinetics in interfacial heterostructure toward efficient energy storage

Abstract

The development of battery-type supercapacitor electrodes faces significant challenges due to poor rate capability and cyclic stability, largely caused by sluggish reaction kinetics. In this study, we report a unique 2D CeO2/ Co3O4 heterostructure designed to enhance energy storage performance in aqueous hybrid systems. By investigating the interplay between cubic Ce-O and octahedral Co-O species, we reveal that distortion-driven electron delocalization and gradient orbital hybridization serve as critical mechanisms for improving charge storage kinetics. Our findings, supported by both experimental data and theoretical calculations, highlight that the distorted geometry at the Co-O-Ce boundary facilitates effective electronic interaction and activates inert 4f states. As a result, the CeO2/Co3O4 heterostructure-based hybrid capacitor achieves an exceptional specific energy (Es) of 57.94 Wh kg-1 at a specific power (Ps) of 1.178 kW kg-1, with an impressive capacity retention of 81.5 % over 10,000 cycles. Notably, it retains an Es of 51.25 Wh kg-1 even at a high Ps of 13.17 kW kg-1, showcasing remarkable charge storage kinetics. This work contributes significantly to the electronic modulation strategies for supercapacitor electrodes, leveraging geometrical distortion and d-f orbital hybridization for enhanced performance.