Optimizing D-band center of tube brush-like CoZn13/Co/ZnO architecture with multiple-heterointerfaces enhancing ion/electron migration toward pseudocapacitive storage

Abstract

The exploration of hierarchical heterostructures with heterointerfaces have proven indispensable for enhancing ion/electron migration of efficient energy storage. Herein, a fascinating design of CoZn13/Co/ZnO hierarchically porous nanostructures (CZCZ HPNs) with rich heterointerfaces concurrently encapsulated into N-doped carbon (NC), growing on three-dimensional Ni foam wrapped by N-doped graphene (denoted as CZCZ/NC HPNs) is showcased for pseudocapacitive storage. The ingeniously construction of CZCZ HPNs/NC features powerful built-in electric field (BIEF) introduced by well-defined heterointerface for boosting electronic/ionic transport dynamics, and unique porous hierarchical architectures for reinforcing the structural and electrochemical stability. Notably, combined with the differential charge density analysis, the BIEF in CZCZ/NC HPNs generated by two heterointerfaces of Co-ZnO and CoZn13-ZnO can offer additional driving forces for promoting electron transfer. The d band centers of different heterojunctions remarkably shift negatively in comparison with those of the monomers, indicative of lower electron/ion transfer energy barrier. Additionally, the CZCZ/NC HPNs as a positive electrode and porous γ-Fe2O3 nanorods wrapped by NC (γ-Fe2O3/NC) as a negative electrode are employed to assemble a soft-packed hybrid supercapacitor device with ultrahigh energy density of ∼107.2 Wh kg−1 at ∼399.9 W kg−1. This work highlights an in-depth fundamental understanding of underlying reaction mechanisms of the heterointerface and structures engineering in constructing other advanced electrodes in sustainable energy storage.