Interface engineering boosts electrochemical performance by fabricating CeO2@CoP Schottky conjunction for hybrid supercapacitors

A novel strategy of boosting electrochemical performance of hybrid supercapacitor cathode based on interface engineering by fabrication of Schottky-type conjunction is proposed. The electrode is composed of binder free 3D CoP nanoflowers decorated by CeO2 nanoparticles, which was directly grown on nickel foam, forming a conjunction interface. Compared to CoP, the CeO2@CoP electrode exhibits remarkable enhanced electrochemical performance. The significantly boosted performance can be attributed to the CeO2@CoP interface, which promotes electrons migration from CoP to CeO2 and eventually forms positive holes on CoP. These positive holes can easily capture more OH-, creating more active sites for redox process. Furthermore, a hybrid supercapacitor full cell composed of CeO2@CoP and activated carbon was assembled, which exhibits outstanding energy storage performance with a specific capacity of 486.5 mC cm(-2) at 1 mA cm(-2) and outstanding cycle stability of 89% after 5000 cycles. The energy density is 55.4 Wh kg(-1) at a power density of 955.9 W kg(-1). This work not only demonstrates that CeO2 is an attractive additive for supercapacitor electrodes, but also provides an experimental/theoretical understanding of the enhanced electrochemical performance by electrons migration process on CeO2@CoP interfaces, which is important for the design of supercapacitors. (C) 2020 Elsevier Ltd. All rights reserved.