Expeditious and eco-friendly hydrothermal polymerization of PEDOT nanoparticles for binder-free high performance supercapacitor electrodes

Abstract

Poly(3,4-ethylenedioxythiophene) (PEDOT) is a promising conjugated polymer that has attracted attention because of its outstanding electronic properties, useful for a wide range of applications in energy storage devices. However, synthesis of high-quality PEDOT occurs via vapour phase polymerization and chemical vapour deposition techniques using extrinsic hard templates or complicated experimental setups. This study introduces a simple hydrothermal polymerization technique using ferric chloride (FeCl₃) as an oxidizing agent to overcome the above drawback, which results in good conductive, crystalline PEDOT nanodendrites and nanospheres. The effects of varying the molar ratio of FeCl₃ oxidant were investigated in terms of the structural, morphological and electrochemical properties of PEDOT. The supercapacitive performance of the as-polymerized PEDOT nanostructures was determined by fabricating an electrode without the aid of organic binders or conductive additives. PEDOT nanodendrites polymerized using 2.5 molar ratio of FeCl₃ demonstrated enhanced electrochemical performance with a maximum specific capacitance of 284 F g⁻¹ with high energy density of 39.44 W h kg⁻¹ at 1 A g⁻¹ current density in 1 M H₂SO₄ electrolyte. Moreover, the sample possessed higher conductivity, better specific surface area, improved electrochemical properties, comparable crystallinity, and excellent cycling stability after 5000 charge/discharge cycles than the other PEDOT nanostructures. Importantly, the results establish that these materials afford good redox behaviors with better conductivity suitable for the development of an organic electrode-based supercapacitor with high specific charge capacity and stability.