Designing of ultra-long-life hybrid supercapacitor based on advanced battery-type electrochemical performance from porous nanostructured nickel-doped bimetallic spinel electrodes

Engineering novel hierarchical nanostructure-based electrode materials with higher surface area remains a great challenge in energy storage field to achieve higher energy density hybrid supercapacitor for portable electronic applications. Herein, mono or mixed/bimetallic Co3O4, ZnCo2O4 and nickel (Ni) ions incorporated ZnCo2O4 (Ni0.05Zn0.95Co2O4) spinels with porous nanostructures were prepared via a simple eco-benign novel wet-chemical approach, followed by calcination. The Ni0.05Zn0.95Co2O4 composite revealed the hierarchical hollow nanospindles with a high specific surface area, and it has the ability to supply more electroactive sites for the diffusion of aqueous electrolyte ions, further assisting the electron transportation in electrochemical analysis. In particular, the Ni0.05Zn0.95Co2O4@Ni foam (NF) electrode revealed a battery-like electrochemical feature and exhibited the specific capacity of similar to 138 mA h g(-1) which is dramatically higher than the ZnCo2O4@NF (similar to 56 mA h g(-1)) and Co3O4@NF (similar to 34 mA h g(-1)) electrodes at 1 A g(-1) due to the strong synergistic effect of Ni and Co ions and rapid reaction kinetics. Additionally, a pouch-type Ni0.05Zn0.95Co2O4@NF//commercial activated carbon@NF hybrid supercapacitor device showed maximum energy and power densities of similar to 54.9 W h kg(-1) and similar to 6105 W kg(-1), respectively. Impressively, the fabricated device further exhibited an ultra-long cycling life (114% capacitance retention after 15000 cycles) and successfully demonstrated its real-time portable electronic applications. (C) 2020 Elsevier Ltd. All rights reserved.