The continuous porous PEDOT:PSS film improves wettability and flexibility of the rGO/CoFe2O4 paper electrodes for symmetric supercapacitors

Nowadays, safe, toughness, flexible and wearable energy storage devices have become a research hotspot. However, the safety and stability of flexible devices are still challenging because traditional wearable energy storage devices are difficult to overcome the problems of leakage, toxic and fragile electrolyte and so on. In this study, we successfully designed and constructed a continuous porous conductive polymer PEDOT:PSS film coated graphene (rGO) and CoFe2O4 nanospheres composite paper electrode material. rGO paper has the advantages of good electrical conductivity and large surface area, but the graphene sheet without oxygen group has very weak adhesion between sheets, and the surface is completely hydrophobic. The water-soluble conductive polymer PEDOT:PSS film successfully increased the toughness and wettability of the graphene composite paper, and the kinetic fitting verified that the polymer improved the rate performance and electrochemical activity of the graphene composite paper. The area specific capacitance, energy density and power density of the symmetric supercapacitor made of rGO/CoFe2O4/PEDOT:PSS paper are 229.6 mF cm−2, 25.9 Wh kg−1 and 135.3 W kg−1. More importantly, the device can be charged in both positive and negative directions, and when change charging direction, the electrochemical performance of the device is also excellent. This solves the safety problem caused by the wrong connection between positive and negative poles of the supercapacitor, and also makes a contribution to the safety development of flexible supercapacitors.