Copper oxide coated stainless steel mesh for flexible electrodes

Low fabrication cost, high specific capacitance and mechanical stability are crucial characteristics of flexible electrodes which could power flexible electronic devices. In this work, copper was coated electrochemically on a stainless steel mesh from an ionic liquid, in this case, a deep eutectic solvent based ionic liquid formed from a mixture of a hydrogen bond donor and a quaternary ammonium salt that is called Ethaline. The composition, structure, and morphology of the copper-coated flexible steel, as dependent on the applied potential in KOH, were investigated. Copper-coated steel was oxidized in OH-based cycling media, where the characterization results demonstrated that the electrode was formed from mainly Cu2O at the reduced and oxidized potential. The electrochemical behaviour of the film in the alkaline electrolyte was elucidated via cyclic voltammetry in terms of potential supercapacitor applications, where the copper-coated steel mesh electrode was found to have a specific capacitance of 119 F g(-1) at 5 mV s(-1). The increased capacitance of the flexible material could be attributed to the rough surface of copper on the microscale steel mesh wires that provided an easily accessible route for the movement of electrolyte ions to/from the modified electrode during oxidation and reduction. Specific capacitance retention remained essentially stable particularly after 100 scans, and presented a long life-cycle even after 1000 cycles. The experimental results demonstrated that an electrochemical reaction did not occur between bare stainless steel mesh and KOH between 0.8 V and 0.3 V, where Cu2O was redox active. Therefore, copper oxide on a flexible mesh can be a negative electrode in flexible energy storage devices.

Automated summary

This study demonstrates the fabrication of flexible electrodes with high specific capacitance and mechanical stability by electrochemically coating copper on a stainless steel mesh. The copper oxide in the electrode showed good electrochemical performance in an alkaline electrolyte. The experimental results suggest that the flexible copper-coated mesh electrode has potential applications in the field of electrochemical supercapacitors.