Представлены результаты синтеза и исследования графенсодержащих порошков из пластиковых отходов методом быстрого джоулева нагрева. Процессы проводились на разработанной на основе предыдущей итерации макета установке быстрого джоулева нагрева. Эксперименты проводились на смеси полипропилена с техническим углем, которая подвергалась высокотемпературному воздействию при различных напряжениях разряда (100 В, 200 В, 300 В). Полученные углеродные порошки были исследованы методами спектроскопии комбинационного рассеяния света, рентгеноструктурного анализа, сканирующей электронной микроскопии с элементным анализом. Результаты показали, что при напряжении разряда 300 В формируется турбостратный графен (turbostratic graphene) с высокой степенью упорядоченности кристаллической структуры, что подтверждается наличием характерных пиков в спектрах комбинационного рассеяния света и рентгеноструктурного анализа. При более низких напряжениях разряда также образуются графеновые чешуйки, но с большим содержанием аморфного углерода. Электрические свойства сформированных пленок на основе полученных углеродных порошков демонстрируют низкое слоевое сопротивление, что делает их перспективными для использования в качестве электропроводящих покрытий и электродов для суперконденсаторов. Предлагаемый метод быстрого джоулева нагрева в перспективе может позволить эффективно перерабатывать пластиковые отходы в ценные углеродные материалы, что может позволить решить экологические проблемы и способствовать развитию «зеленых» технологий.

The rapid development of electric vehicles, unmanned aerial vehicles, and wearable electronic devices has led to great interest in research related to the synthesis of graphene with a high specific surface area for energy applications. However, the problem of graphene synthesis scalability, as well as the lengthy duration and high energy intensity of the activation processes of carbon materials, are significant disadvantages. In this study, a novel reactor was developed for the green, simple, and scalable electrochemical synthesis of graphene oxide with a low oxygen content of 14.1%. The resulting material was activated using the fast joule heating method. The processing of mildly oxidized graphene with a high-energy short electrical pulse (32 ms) made it possible to obtain a graphene-based porous carbon material with a specific surface area of up to 1984.5 m²/g. The increase in the specific surface area was attributed to the rupture of the original graphene flakes into smaller particles due to the explosive release of gaseous products. In addition, joule heating was able to instantly reduce the oxidized graphene and decrease its electrical resistance from >10 MΩ/sq to 20 Ω/sq due to sp² carbon structure regeneration, as confirmed by Raman spectroscopy. The low energy intensity, simplicity, and use of environment-friendly chemicals rendered the proposed method scalable. The resulting graphene material with a high surface area and conductivity can be used in various energy applications, such as Li-ion batteries and supercapacitors.

The present study outlines the synthesis of carbon that include graphene flakes. The production process employed rapid Joule heating of a mixture consisting of finely dispersed polypropylene powder and carbon black in a 1:1 ratio. An experimental model of the installation was developed and constructed, based on a capacitor bank with a total capacitance of 32 mF and an inductor with a nominal value of 24 mH for production purposes. A solution was prepared that included a colloidal dispersion of epoxy resins, an amine hardener in a mixture of deionized water and ethyl alcohol in a ratio of 4:0.6:10, along with 1 wt. % of the resulting carbon powder and carbon black, to be used as an impregnating compound for glass fibers. The estimated synthesis temperature reached up to 2200 °C, with a duration of approximately 32 ms. Studies of Raman spectra and optical density in the UV range indicate that the synthesized carbon powders contain graphene flakes with lateral dimensions of up to 13 nm. The results of elemental analysis reveal a significant increase in the carbon atom content in the impregnated fiber compared to the original glass fiber. Electrical measurements of the temperature dependence of the current-voltage (C-V) characteristics demonstrated the presence of electrical conductivity at low temperatures, corresponding to a resistance of up to 8 MΩ/sq. In the future, electrical conductivity may be enhanced by increasing the discharge power. The developed configuration for fast Joule heating has the potential to be integrated into the field of efficient recycling of plastic waste. The resulting carbon powders can serve as modifying additives for glass fiber used in the production of fiberglass concretes.

The rapid development of electric vehicles, unmanned aerial vehicles, and wearable electronic devices has led to a high interest in research related to the synthesis of graphene with a high specific surface area for energy applications. However, the problem of graphene synthesis scalability, as well as the lengthy duration and high energy intensity of the activation processes of carbon materials, are significant disadvantages. In this study, a reactor was developed for the green, simple, and scalable electrochemical synthesis of graphene oxide with a low oxygen content of 14.1 %. The resulting material was activated using a fast joule heating method. The processing of mildly oxidized graphene with a high–energy short electrical pulse (32 ms) made it possible to obtain a graphene–based porous carbon material with a specific surface area of up to 1984.5 m2/g. The low energy intensity, simplicity, and use of environmentally friendly chemicals render the proposed method scalable.

The development of economical and scalable methods for synthesizing high-quality graphene remains a pivotal challenge in materials science. This study presents an efficient approach for synthesizing turbostratic graphene with micron-sized domains from an accessible bioprecursor-activated charcoal—using fast Joule heating. We demonstrate that ultra-rapid thermal annealing (~16.2 kJ/g, up to 3000 K) triggers a phase transition from amorphous carbon to a highly graphitized structure. Comprehensive characterization via SEM, AFM, Raman spectroscopy, and XRD revealed the formation of large flakes with lateral dimensions up to 1.5 µm and thicknesses ranging from 4 to 200 nm. Raman mapping further uncovered a heterogeneous structure with alternating regions exhibiting different degrees of interlayer coupling, characteristic of turbostratic stacking. The key feature of the material is its turbostratic layer stacking, confirmed by the combination of XRD data showing an interlayer distance of 3.436 Å and Raman spectra characteristic of decoupled graphene layers. The synthesized material exhibits excellent electrical transport properties, with a bulk resistivity of 0.51 Ω·cm—an order of magnitude lower than that of the initial charcoal. These findings highlight the potential of the developed method for producing electrode materials for energy storage devices and conductive composites.

This paper presents the results of the investigation and synthesis of graphene-containing powders from plastic waste using the fast Joule heating method. The processes were carried out on a equipment for fast Joule heating, which was developed based on a previous iteration of the prototype. Experiments were conducted on a mixture of polypropylene and carbon black, which was subjected to high-temperature treatment at various discharge voltages (100 V, 200 V, 300 V). The resulting carbon powders were analyzed using Raman spectroscopy, X-ray diffraction, and scanning electron microscopy with elemental analysis. The results demonstrated that at a discharge voltage of 300 V, turbostratic graphene with a high degree of crystallographic order was formed, as confirmed by the presence of characteristic peaks in the Raman spectra and X-ray diffraction patterns. At lower discharge voltages, graphene flakes were also formed, but with a higher content of amorphous carbon. The electrical properties of the films produced from the obtained carbon powders exhibited low sheet resistance, making them promising for use as conductive coating and electrodes for supercapacitors. The proposed fast Joule heating method has the potential to efficiently convert plastic waste into valuable carbon materials, which could address environmental challenges and contribute to the development of “green” technologies.