Construction of three-dimensional nanocube-on-sheet arrays electrode derived from Prussian blue analogue with high electrochemical performance

Constructing porous three dimensional (3D) structure is an effective strategy for electrode materials to solve the urgent problem of low utilization of active sites in pseudocapacitors. Herein, the in situ scaffolding formation of well-distribute 3D NiFe Prussian blue analogue (NiFe PBAs) nanocubes penetrated 2D NiFe-layered double hydroxides (NiFe LDHs) on stainless steel mesh (SS) are synthesized, and then the precursors are transferred into 3D oxide arrays (SS@NiFe NSs@NiFe NCs) via thermal annealing in air. The 3D arrays show high specific surface area as well as excellent electrochemical performance including a high specific capacity and an outstanding cycling performance. Density functional theory (DFT) is also used to investigate reasons for the enhanced electrochemical performance of SS@NiFe NSs@NiFe NCs, and results show that the self-built heterointerfacial can form a long-range continuous interfaces, thereby increasing the conductivity and facilitate the charge transfer. In addition, a hybrid supercapacitor (HSC) SS@NiFe NSs@NiFe NCs//SS@Fe2O3 device is assembled and show an impressive electrochemical performance. This work gives a new insight for rational design of 3D PBA-based functional nanomaterials and can be used to explore the mass transfer mechanism of supercapacitor based on the special open structure of PBAs.