Template-free route to PEDOT nanofibers for 3D electrodes with ultrahigh capacitance and excellent cycling stability

The rapid growth of the electronics industry has increased the demand for electrochemical capacitors with a combination of high capacitance, high energy and power density, and long cycling stability. To achieve this, a rational design of electrode materials with high surface area, suitable porosity, and excellent electronic and ionic conductivity is required. Herein, high aspect ratio poly(3,4-ethylenedioxythiophene) (PEDOT) nano and microfibers with increased accessible surface area and porosity are grown on a three-dimensional laser-scribed graphene (LSG) network through a facile vapor phase polymerization process. The resultant electrode showed an outstanding areal capacitance of 1463 mF cm-2. To the best of our knowledge, this is the highest value reported so far for a vapor phase polymerized PEDOT/LSG supercapacitor. It also displayed an impressive capacitance retention of over 89.7% after 10,000 cycles at a current density of 30 mA cm-2 with a potential window of 1.0 V. Furthermore, the capacitive current contribution is a remarkable 96% with a maximum energy and power density of 75.21 & mu;Wh cm-2 and 136 mW cm-2, respectively. This binderless nanofiber composite electrode offers the advantages of better adhesion, improved specific surface area, suitable porosity, and enhanced electronic and ionic conductivity.