Characteristics of Power Supercapacitor with Electrodes Made of Composite Carbon Nanopaper Based on Carbon Nanotubes and Resorcinol–Formaldehyde Xerogel

The nanocomposite of a resorcinol–formaldehyde xerogel and carbon nanotubes after carbonation was obtained in the form of a composite carbon nanopaper (CCNP) with the thickness of 100–300 microns, the density from 0.1 to 0.5 g/cm³ and the electronic conductivity of more than 10 S/cm. The microporous structure of the nanopaper is formed by carbonized resorcinol–formaldehyde xerogel, and the mesoporous structure is formed by the nanotube framework. Previously, the characteristics of nanopaper electrodes in an aqueous electrolyte of 1M H₂SO₄ were measured, where the maximum capacitance was 155 F/g (56 F/cm³). To work with an organic electrolyte, a method for activating CCNP with potassium hydroxide has been developed. In this paper the characteristics of electrodes made of activated nanopaper (a-CCNP) in an organic electrolyte 1 M 1,1-Dimethylpyrrolidinium tetrafluoroborate (DMPBF₄)/acetonitrile solution were measured. The capacitance in this electrolyte has been reached 70 F/g (27 F/cm³). According to measurements on a laboratory assembly of a symmetrical supercapacitor (SC) with electrodes made of CCNP, the characteristics are calculated when the SC operates in the mode of short pulse switching with an efficiency of EF = 95%. In an aqueous electrolyte of 1 M H₂SO₄ (U₀ = 1.0 V), the volumetric energy density was E_0.95,SC = 0.9 W h/L and the volumetric power density was P_0.95,SC = 2.1 kW/L. In 1 M DMPBF₄/acetonitrile electrolyte (U₀ = 2.7 V), the design characteristics of the capacitor were: volumetric energy density E_0.95,SC = 3.8 W h/L and volumetric power density P_0.95,SC = 2.0 kW/L. The specific characteristics of power SCs are compared with electrodes made of activated CCNP and of other carbon materials. In mass production, nanocomposite electrodes are estimated to be cheaper than activated carbon microfibers and significantly cheaper than graphene electrodes.