A three-dimensional heterogeneous ZnCo-PBA@α-Co(OH)2 nanostructure for high-performance supercapacitors

Abstract

In this work, we designed a simple hydrothermal synthetic method for a ZnCo-PBA@α-Co(OH)2 nanosphere@nanosheet material with good electrochemical properties. The obtained material had a specific capacitance of 423.92 F g−1 at 1 A g−1 and a cycling retention ratio of 78.48% after 1000 cycles at 5 A g−1. A hybrid supercapacitor device (ZnCo-PBA@α-Co(OH)2//AC) assembled with activated carbon as the negative electrode had a specific capacitance of 122.4 F g−1 at 1 A g−1, a cycling retention rate of 73.53% after 5000 cycles at 5 A g−1, and a very high energy density of 49.13 Wh kg−1 at power density of 1734.0 W kg−1. The significantly improved electrochemical performance of the ZnCo-PBA@α-Co(OH)2 nanocomposites can be attributed to the positive synergistic effects of the porous structure of the PBA material and the large specific surface area of the α-Co(OH)2 nanosheets, on the ion permeability and number of active sites in the reinforcing material; thus, this composite is a potential material for use in future energy storage systems.