Features of Obtaining Composite Electrode Material of a CNT/RuO2·xH2O Supercapacitor by Electrophoretic Codeposition

Abstract: For the solution of the problem of energy storage, new and more efficient functional electrode materials for electrochemical devices such as supercapacitors and their formation technologies are being developed. In particular, using the method of electrolyte-free electrophoretic codeposition, a composite material of carbon nanotubes (CNTs)/RuO2·xH2O with high specific capacitance and power values can be obtained. In this study, the optimal composition of a 50-mL suspension for electrophoretic deposition (EPD) is determined by sedimentation analysis. It is demonstrated that in the course of the iodoform reaction with acetone, I2 (20 mg) ensures the saturation of particle surfaces with protons and their deposition on the cathode, thus replacing the electrolytes that introduce impurities into the final coating. It is established that the presence of a dispersing agent (5 mg of hydroxypropyl cellulose) is required in the suspension to maintain stability. The possibility of removing hydroxypropyl cellulose during annealing in air at a temperature of about 260°C is studied and confirmed by the methods of differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). Composite material, processed in this way and obtained from a suspension containing double-walled CNTs and RuO2·xH2O, equal to 2 and 10 mg, respectively, has a capacity of 21.5 and 8.6 mF/cm2 at cyclic sweep rates of 10 and 100 mV/s, respectively. It is established that elevated temperatures and prolonged heat treatment lead to a deterioration in the electrochemical characteristics due to the degradation of RuO2·xH2O and the CNTs. © Pleiades Publishing, Ltd. 2023. ISSN 1063-7397, Russian Microelectronics, 2023, Vol. 52, No. 7, pp. 587–598. Pleiades Publishing, Ltd., 2023. Russian Text The Author(s), 2023, published in Izvestiya Vysshikh Uchebnykh Zavedenii, Elektronika, 2023, Vol. 28, No. 1, pp. 59–78.