Electrochemical deposition of porous CoMnS–PDA onto ITO/PET for high-performance all-solid-state flexible transparent supercapacitors

Abstract

The CoMnS–PDA (polydopamine) composite electrode, featuring high optical transparency and mechanical flexibility, was fabricated on ITO/PET (indium tin oxide/polyethylene terephthalate) substrates via a one-step electrochemical deposition method. By combining the rich redox activity of bimetallic sulfides with the adhesive, nitrogen-rich structure of PDA, the electrode achieves superior surface modification and pseudocapacitive behavior. The CoMnS–PDA electrode demonstrates a high areal capacitance of 189.3 mF cm⁻² at 0.4 mA cm⁻² while maintaining an optical transmittance of ∼80%. A symmetric supercapacitor assembled with these electrodes achieves 50% transparency and delivers an areal capacitance of 28.7 mF cm⁻² at a current density of 0.2 mA cm⁻². The device retains 84.3% of its initial capacity after 6000 cycles and maintains performance even under ∼180° bending. Furthermore, three devices in series can power a red LED, highlighting the potential of this platform for next-generation transparent and flexible energy storage applications.