Essential role of the interfacial interaction in the core-shell electrode for its enhanced electrochemical performance

Abstract Interfacial interaction in the core-shell hybrid materials makes a great influence for the enhanced electrochemical performances. In this paper, to explore the essential role of the interfacial interaction in the core-shell hybrid electrodes, we prepare a simple mutually-coupled 3D heterogeneous core/shell electrode by NiFe PBAs (Prussian blue analogues) (shell) depositing on the surface of NiFe LDH (layered double hydroxides) (core). The elements of Fe and Ni in NiFe LDH can partly replace the original connections in the NiFe PBAs thus forming a strong interfacial coordination bonding between LDH and PBAs (Fe/Ni(LDH)–CN–Fe/Ni(PBAs) or O–Fe/Ni(PBAs)). Electrochemical tests show that the hybridization present excellent electrochemical performances with a high capacity of 1351 F g−1 at 1 A g−1, which is much higher than that of PBAs-based electrodes recently report. In-situ Raman spectroscopic analysis shows that NiFe LDH@NiFe PBAs present enhanced Faradic redox reaction during charging/discharging process, which is owing to the strong interfacial interaction between two phases. The density functional theory (DFT) calculations results demonstrate that the strong connection bonding can improve the electrical conductivities greatly. This work underscores the crucial role of interface coupling interaction between core and shell and give a new perspective to design core-shell hybrid electrode with excellent electrochemical performance.