Layered graphite foil/poly(3,4-ethylenedioxythiophene) electrode-enabled flexible electrochemical capacitors with observably boosted performances

Abstract

• A simple mechanically exfoliated method is proposed to prepare LGF current collector. • LGF shows a unique layered microstructure with observably enlarged surface area. • The electrochemical properties of PEDOT are significantly affected by polymerized parameters. • LGF-constructed electrodes show observably enhanced electrochemical properties. • LGF/PEDOT flexible EC features high electrochemical properties and mechanical flexibility. Seeking a cheap flexible current collector and further enhancing charge storage capacity are still two crucial challenges to promote the practical applications of flexible electrochemical capacitors. In this work, we first fabricate layered graphite foil (LGF) current collector from low-cost GF by a facile and scalable mechanically exfoliated method. And meanwhile, the electropolymerization parameter-dependent supercapacitive performance of the poly(3,4-ethylenedioxythiophene) (PEDOT) as the electroactive material is investigated in detail. Electrochemical measurements verify that the electrochemical performances of PEDOT are notably improved via optimizing the electropolymerization parameters. More importantly, the capacitive behaviors of PEDOT electrodes are further observably boosted through using LGF current collector compared to GF, attributed to the 3D interface established between the PEDOT films and LGF. The LGF/PEDOT electrodes yield an areal-specific capacitance of 122.3 mF cm −2 and achieve high rate capability. Furthermore, a symmetrical electrochemical capacitor assembled by the LGF/PEDOT electrodes show superior electrochemical capacitive properties and highly mechanical flexibility. Even more impressively, it retains 92.1% and 94.3% of initial capacitance after 10,000 charge–discharge cycles and harsh mechanical deformation for 500 times, respectively. The LGF we develop not only ensures its high flexibility but distinctly enhances its electrochemical properties.