Engineering of both binder-free CuCo2O4 nanorod@CuO flower-like nanosheet core-shell heterostructure and NiFe2O4 nanoflake electrodes for asymmetric supercapacitor

Researchers are continuing to create novel energy storage materials with ultrahigh performance to develop faster and more efficient energy storage devices. The performance and stability of low-cost materials for electrochemical energy storage systems are important factors. In this study, hierarchical CuCo2O4 nanorod @CuO flower-like nanosheets are directly fabricated on flexible stainless steel mesh (FSSM) via a two-step method that involves hydrothermal and chemical bath deposition (CBD). The microstructure and chemical composition of the composites were systematically examined by applying techniques such as XRD, SEM, TEM, and XPS. The synergistic effect of CuCo2O4 nanorods and CuO flower-like nanosheets imparts significant enhancement properties to electrode materials. The improved CuCo2O4@CuO core-shell heterostructure, a binder-free electrode, displays outstanding electrochemical performance. In comparison to the individual constituent CuO and CuCo2O4 electrodes, the CuCo2O4@CuO core-shell heterostructure electrodes demonstrated a higher surface area of 159.00 m2 g−1 and a high specific capacitance of 1243.2 F g−1 at a high current density of 10 mA cm−2 and acceptable cycle stability (under the current density of 20 mA cm−2, after 5000 cycles, the capacitance retention rate is 83 %). Furthermore, the asymmetric supercapacitor (ASC) was built with the CuCo2O4@CuO electrode as the positive electrode and the NiFe2O4 electrode as the negative electrode to demonstrate its practical applicability in energy storage devices. The ASC device can attain a maximum energy density of 43.83 W h kg−1 at a power density of 0.318 k W kg−1. Thus, these electrochemical performances demonstrated that as-synthesized CuCo2O4@CuO core-shell heterostructure is a favorable candidate as electrodes for high-performance supercapacitors.