Construction of Cu(OH)2/PBAs nanorod array heterostructures for high performance of hybrid supercapacitors

Abstract

Copper-based oxides and hydroxides have attracted much attention due to their outstanding electrochemical activity, considerable theoretical capacity and excellent environmental compatibility. Moreover, they have low cost, abundant reserves and low toxicity. Prussian blue analogues (PBAs) have high porosity and high specific surface area, which can provide more abundant and efficient channels for the transmission of electrons, further enhancing their application potential. By combining the two materials and utilizing their synergistic effects, we obtain heterostructured electrode materials with good electrochemical performance. Therefore, this study adopted an innovative method to grow Cu(OH)₂ on the copper foam substrate. Subsequently, a part of them was transformed into Prussian blue analogues (PBAs) through a hydrothermal reaction, making use of the synergy effect of the two. This strategy not only endows the material with a unique heterogeneous structure, but also significantly improves its electrochemical performance, thereby obtaining the high-performance electrode material of Cu(OH)₂/PBAs. At 1 A g⁻¹, this composite material has a good specific capacitance (896.69 F g⁻¹). When assembling it into a hybrid asymmetric button-type supercapacitor, it also exhibits good specific capacity (1457.5 F g⁻¹), energy density (518.22 Wh kg⁻¹), power density (1599.99 W kg⁻¹), and excellent cycling performance. After 6000 charge and discharge cycles, the specific capacity retention rate still reaches 99.67 %. Therefore, Cu(OH)₂/PBAs heterostructured composites have great potential for application as electrode materials.