Bundlelike CuCo₂O₄ Microstructures Assembled with Ultrathin Nanosheets As Battery-Type Electrode Materials for High-Performance Hybrid Supercapacitors

In this work, bundlelike CuCo2O4 microstructures (CuCo2O4 BMs) assembled with ultrathin nanosheets were fabricated through employing an easy and scalable hydrothermal method along with an extra thermal treatment in air. These CuCo2O4 BMs possessed a specific surface area as large as 114.36 m2 g–1 and a mean pore size of 10.99 nm with pore size distribution at 1.88 nm. The electrochemical behavior was evaluated in 2 M KOH solution. It demonstrated that the CuCo2O4 BMs exhibited the typical features of battery-type electrode material with a specific capacity up to 303.22 C g–1 at 1 A g–1, a rate capability of 69.77% at 10 A g–1, and 71.8% capacity retention after 5000 cycles at 5 A g–1. A hybrid supercapacitor (HSC) was assembled with CuCo2O4 BMs as the cathode and activated carbon as the anode, respectively. The HSC exhibited a specific capacity of 152.25 C g–1 at 1 A g–1 with 111.75% retention over 5000 cycles and delivered a remarkable energy density of 39.95 W h kg–1 at 944.63 W kg–1 and still maintained 27.06 W h kg–1 even at 8.06 kW kg–1. By virtue of these impressive electrochemical performances, the CuCo2O4 BMs can serve as a promising battery-type electrode material toward high-performance hybrid supercapacitors and other energy-storage systems.