The preparation and electrochemical properties of PEDOT:PSS/MnO2/PEDOT ternary film and its application in flexible micro-supercapacitor

Micro-supercapacitors are promising energy storage devices that can complement batteries in miniaturized portable electronics and microelectromechanical systems. Here, we develop a facile method to fabricate a hierarchically structured film as electrode material of micro-supercapacitor. A poly (3,4-ethylenedioxythiophene):poly (styrenesulfonate)/manganese dioxide/poly (3,4-ethylenedioxythiophene) (PEDOT:PSS/MnO2/PEDOT) ternary film is prepared via a two-step process. Firstly, MnO2 nanoparticles are directly synthesized in the PEDOT:PSS matrix and the PEDOT:PSS/MnO2 mixed solution is spin-coated on the substrate. Then a porous PEDOT film is synthesized by the vapor phase polymerization (VPP) on the PEDOT:PSS/MnO2 precursor film. Electrochemical tests reveal that the ternary film exhibits a high specific capacitance of 391.36 F/cm3 at current density of 3.75 A/cm3, as well as excellent cycle stability with capacitance retention of 92% after 5500 cycles. The volumetric capacitance of PEDOT:PSS/MnO2/PEDOT-microsupercapacitor achieves 13.64 F/cm3. The excellent electrochemical performances indicate that each component in the hybrid film provides unique and crucial function to achieve optimized electrochemical properties. As a result, this ternary composite film shows promising future as electrode material for electrochemical energy storage devices.