Electrochemistry Deposition of CoMnS-PDA onto ITO/PET for High-Performance All-Solid-State Flexible Transparent Supercapacitors

The CoMnS-PDA (polydopamine) composite electrodes with high optical transparency and flexibility were fabricated on ITO/PET substrates via an electrochemical deposition method. The unique structural attributes, tunable electronic properties, and rich redox states inherent to bimetallic sulfides, combined with the catechol and nitrogen functional groups present in PDA, collectively enhance the surface modification effectiveness and pseudocapacitive performance of the electrodes. The CoMnS-PDA electrodes exhibit excellent pseudocapacitive performance, with a maximum areal capacitance of 189.3 mF cm−2 at a current density of 0.4 mA cm−2, while maintaining optical transmittance of around 80%. The assembled symmetric device exhibits 50% transparency and delivers an area capacitance of 28.7 mF cm−2 at a current density of 0.2 mA cm−2. Moreover, the device demonstrates outstanding flexibility, with negligible electrochemical performance degradation even under nearly 180° bending. When three devices are connected in series, they successfully light up a red LED, indicating the promising potential of these materials for flexible and transparent energy storage applications.