Application of multistep electrospinning method for preparation of electrical double-layer capacitor half-cells

• Novel method for preparations of EDLC half-cells.
• Electrospun composite electrodes with low thickness and density.
• Novel electrodes with very small characteristic time constant 0.043 s.
• EDLCs based on electrospun half-cells with very high specific energy and power values.

Electrochemical characteristics of the two identical electrospun micromesoporous carbon electrodes and polymer membrane based half-cells, prepared using the electrospinning method, have been studied in 1 M triethylmethylammonium tetrafluoroborate solution in acetonitrile, using cyclic voltammetry, constant current charge/discharge, constant power discharge and electrochemical impedance spectroscopy methods. The novel electrical double-layer capacitor (EDLC) half-cell preparation method consisted of two steps, at first the nanowire polymer separator layer has been prepared by electrospinning method using poly(vinylidene fluoride) (PVDF) solution in N,N − dimethylformamide and acetone mixture. Thereafter, the electrode material layer has been directly electrospun onto the separator layer from the mixture of carbon (90% commercial RP-20 carbon + 10% few layered graphene) and PVDF solution in N,N − dimethylformamide + acetone mixture. Applying the novel composite electrode preparation method we are able to prepare composite electrodes for EDLC with lower density and thickness than using the widely used traditional roll-pressing method. The wide region of ideal polarizability, high specific capacitance, low equivalent series resistance, short characteristic time constant and high specific energy and specific power values for the completed EDLC have been obtained and discussed.