Microbiologically incorporated cementitious materials to recuperate the activities and toughness of the concrete structures are a new aspect of research work in the current era. The uses of different chemicals and additive in concrete composites sometimes cause health problems which are environmentally unacceptable. In this study we have designed an eco-friendly bio-engineered with high strength and more durable concrete/geopolymer material by incorporating hot spring bacteria. A novel thermos-stable and high pH tolerant silica leaching protein ((M.W. ~ 28KDa) originally isolated from one of the hot spring’s bacteria BKH2 of Bakreshwar, West Bengal [1, 2] has been observed for responsible for production of high-performance structural materials. The corresponding gene of the protein has been identified and cloned into B. subtilis bacterial strain to develop an eco-friendly microbial agent [2, 3]. The transformed bacterial cells, when incorporated to the cement-sand mixture and or fly ash mixed cement-sand mixture, develop a sustainable and energy efficient material, which is useful for construction purposes [3, 4]. Improvement of compressive strength (> 30 – 40%), ultrasonic pulse velocity, sulphate and chloride ions resistant and decrement of water absorption capacity are noted in the bacteria amended mortar/concrete/geopolymer specimens. Micro-structural analyses confirmed the formation of a novel Gehlenite (Ca₂Al₂SiO₇) phase besides calcite deposition inside the matrices of the transformed bacteria-amended cementitious materials [3-5]. This development significantly increases the true self-healing property and aims towards the production of green cement-alternative by using cent-percent fly ash which is sustainable for a prolonged period [5]. This implies lesser requirements of cement and lowers the cost of construction. This study demonstrates a new approach towards the development of Green Home technology by reducing Green House effect of cement production.

In oil and gas fields, once drilling operations conclude, the wells undergo permanent plugging and abandonment (P&A), a crucial phase in their lifecycle. P&A aims to safely seal inactive wells to prevent environmental contamination and hazards. In Norway, increased attention to this phase arises as numerous wells are slated for permanent closure in the near future [1]. Compliance with specific NORSOK standards dictates the use of well-barrier materials tailored to stringent requirements [2].

Historically, cement has served as the primary well-barrier material for P&A activities. However, inherent drawbacks such as shrinkage, poor bonding, and susceptibility to gas migration have spurred exploration into alternative materials offering enhanced mechanical strength and sealing performance. Among these alternatives, bismuth-based alloys stand out as promising candidates.

This article aims to disseminate innovative endeavours from industry and academia alike, addressing the challenges of fluid and gas migration while achieving well integrity and environmental protection. It provides an introductory overview of bismuth-based alloys as potential well-barrier materials, focusing on the detailed description of the BiSn alloy. This includes a comprehensive analysis of its microstructure, laboratory mechanical testing, and simulations to assess its suitability for application within the wells [3], [4]. Additionally, the article examines diverse practices employed by different industry stakeholders utilizing the same material [5]. 

Overall, this article effectively communicates the significance of P&A operations, the necessity for advanced well barrier materials, and ongoing collaborative efforts between industry and academia to meet these challenges. It contributes to the advancement of environmentally responsible well-abandonment practices. 

Carbon fiber microelectrodes (CFMEs) have been used to detect neurotransmitters and other biomolecules using fast-scan cyclic voltammetry (FSCV) for the past few decades. Here, we measure neuropeptides such as Neuropeptide Y and Oxytocin, a pleiotropic peptide hormones that are important for social behavior. These neuropeptides function as anti-inflammatory agents and serves as antioxidants with protective effects during trauma. Since oxytocin and Neuropeptide Y contain tyrosine, a modified sawhorse waveform was also used to detect these neuropeptides. Additionally, we demonstrate that applying the MSW on CFMEs allows for real time measurements of exogenously applied neuropeptides on rat brain slices. These results may serve as novel assays for neuropeptide detection in a fast, sub-second timescale with possible implications for in vivo measurements and further understanding of the physiological role of these neuropeptides.

We also developed enzyme modified microelectrodes for the measurement of glutamate, which is an important excitatory amino acids and biomarker for epilepsy along with the inhibitory GABA. Since glutamate is not redox active at carbon electrodes, we modified CFMEs with glutamate oxidase enzyme to metabolize glutamate to hydrogen peroxide and alpha-ketoglurarate, which was then oxidized at carbon electrodes. The enzyme coating was optimized by varying the concentration of enzyme, chitosan binder, solvent, and deposition time. The coating was further analyzed electrochemically and imaged with scanning electron microscopy (SEM) for thickness and uniformity of surface coverages. Glutamate oxidation was found to be adsorption controlled to CFMEs and characterized at various scan rates, concentrations, and stability times as well with an approximate 100 nM limit of detection.  Glutamate was co-detected in complex mixtures with several monoamines such as dopamine, serotonin, and others in addition to future in vitro, ex vivo, and in vivo studies.

ABO_3-δ perovskite-type oxides are known for their compositional flexibility, possible formation of various orderings in the cationic and anionic sublattices, and a broad range of resulting physicochemical properties. Those properties can be tuned for a particular application, including usage in reversible Solid Oxide Cells (SOCs), as well as for the oxygen storage in pressure swing-type processes.
This work summarizes general guidelines for designing effectively-working perovskite-type oxygen electrodes in SOCs, as well as presents possibility of obtaining oxygen storage materials (OSMs) with the high capacity and low operation temperature. In particular, the A-site layered RE(Ba,Sr)Co_2-yMn_yO_5+δ (RE: selected rare-earth cations; 0 ≤ y ≤ 2) oxides are discussed in more details, as it can be shown that the properly selected Mn substitution results in the high electrocatalytic activity toward the oxygen reduction reaction (ORR), while different Mn content is preferred for the oxygen storage processes [1, 2]. Less commonly studied substitution with Cu is also shown as the effective way of altering physicochemical characteristics, and allows designing electrocatalytically-active RE(Ba,Sr)Co_2-yCu_yO_5+δ series [3]. Furthermore, Co-free La_1-x(Ba,Sr)_xCuO_3-δcompositions can be also designed and obtained, showing promising performance when used as the SOC oxygen electrodes [4, 5]. Notably, the recently emerging high entropy approach provides unique new opportunities, as the resulting multicomponent perovskites may exhibit properties crossing the commonly observed rule of mixtures [6].

Today, Li-ion batteries play a vital role as energy storage devices, dominating both, the market for portable electronic products, and the electric vehicles (EV) sector. The burgeoning EV market is pushing for greater cruising ranges, which necessitates the development of novel, high-energy density cathodes and anodes. In terms of cathode materials, there are currently two noteworthy approaches. One involves further development of Ni-rich layered oxides, with Ni content above 0.9 [1], while the other one focuses on Li- and Mn-rich oxides, which possess specific structural properties [2]. Both groups of materials hold promise for significant advancements in constructing high-capacity and high-power density cells, thanks to their very high reversible discharge capacity (> 200 mAh g^-1), high operating voltage (~3.7 V vs. Li/Li⁺), and relatively low costs. However, these oxides still face severe issues, including surface sensitivity, structural problems such as Li/Ni mixing effects, and inadequate thermal stability, which limit their practical application. Of particular concern is the presence of lithium residuals like LiOH/Li₂CO₃ in the active material, stemming from the synthesis process. Concerning the anode, a particularly interesting direction is combining conversion and alloying reaction mechanisms within a single compound (so called conversion-alloying materials, CAMs) [3]. However, CAMs still suffer from insufficient cycling stability and the only solution proposed in the literature so far is to employ advanced synthesis methods and additives, which are often expensive and difficult to scale. Conversely, the recently discovered high-entropy oxides (HEOs) show excellent cyclability when used as anodes in Li-ion cells, regardless of the synthesis method and resulting particle size.

Combining the above concepts, in this study we synthesized and systematically characterized selected Ni-rich LiNi_0.905Co_0.043Al_0.052O₂ (NCA905) and Li- and Mn-rich Li_1.2Ni_0.13Mn_0.54Co_0.13O₂ (NMC135413) cathode materials. Cathode layers were then obtained, with high active material loadings of ca. 6 mg cm^-2. Both types of cathodes were assembled initially alongside standard graphite anode, and also with the novel high-entropy Sn_0.8(Co_0.2Mg_0.2Mn_0.2Ni_0.2Zn_0.2)_2.2O₄-based anode. Various issues related to combining those electrodes into full cells were studied, including the selection of negative/positive ratio, electrode prelithiation process, and electrolyte additives. The resultant optimized full cells exhibited very good electrochemical performance. For example, the NMC135413@Graphite anode full cell delivered an initial discharge capacity of more than 186 mAh g^-1 at 0.5 C current density (cathode limited), and a very high energy density of 370 Wh kg^-1. A capacity retention of 80% was measured after 400 cycles, indicating very promising electrochemical characteristics.

Molten Carbonate Fuel Cells (MCFCs) are a relatively recent development in fuel cell technology, with applications ranging from small to large scale power generation systems. The interconnect is the part of the MCFC to which the anode and cathode are attached and through which the electrical current generated by the cell is conducted. Therefore, the interconnect must not only be mechanically strong and resistant to oxygen and hydrogen, but also maintain high electrical conductivity and corrosion resistance (including on the surface of the interconnect) at high temperatures (550...650°C) for long periods.

Interconnections (0.3-0.5 mm thick) made of stainless steel (which contains 16-18% Cr and has a high density γ ~ 8 g/cm3) lose surface electrical conductivity due to oxidation. MAX phases Ti₂AlC₃ and Ti₂AlC have two times lower density (γ ~ 4.1 - 4.3 g/cm³) than stainless steel, are stable in oxygen and hydrogen atmosphere at high temperature, and have high electrical conductivity. Therefore, the MAX phase based coatings are potentially promising for this application. OT4-1 titanium alloy substrates with protective coatings are being developed for use as interconnects for MCFCs to replace 316L stainless steel.

Ti-Al-C, (Ti,Mo)-Al-C and (Ti,Cr)-Al-C coatings were deposited on OT4-1 alloy substrates by hybrid magnetron sputtering and cathodic arc evaporation. For magnetron sputtering, a MAX phase (Ti₂AlC - 63 wt.% and Ti₃AlC₂ - 37 wt.%) target prepared by hot pressing of TiC, Al and TiH₂ under 20 МPа, at 1350 °С for 10 min was used. Simultaneously with magnetron sputtering of the MAX phase target, chromium or molybdenum was deposited using a cathodic arc plasma source. Three types of coatings were deposited: Ti-Al-C magnetron-only and hybrid (Ti,Mo)-Al-C and (Ti,Cr)-Al-C. The thickness of the deposited coatings was 5-11 µm.

X-ray diffraction analysis showed that all deposited coatings are close to amorphous state. The SEM-EDX study indicated that the average composition of the coatings obtained from the MAX phase based target was Ti₂Al_1.0-1.1C_1.1-1.3 (close to 211), for the coating with additions of Mo: Ti₂ Mo_2.1Al_0.9C_2.8 (close to 413) and Cr: Ti₂Cr_2.6Al_0.8C_1.5. The nanohardness of the coatings varied from 11 to 15 GPa and the Young's modulus from 188 to 240 GPa.

The (Ti,Cr)-Al-C coating showed the highest stability against electrochemical corrosion in 3.5 wt.% NaCl aqueous solution at 20 °C: corrosion potential E_corr = 0.044 V, corrosion current density i_corr = 2.48×10^-9 A/cm², anodic current density i_anodic (at 0.25 V vs. SCE) = 5.18×10^-9 A/cm². This coating also showed the highest long-term oxidation resistance and after heating in air at 600 °C, 1000 h its electrical conductivity s= 9.84×10⁶ S/m was slightly higher than before heating s= 4.35×10⁵ S/m, the nanohardness and Young's modulus are in the range of 15 GPa and 240 GPa, respectively. The increase in electrical conductivity after long-term heating at 600 °C can be explained by the observed crystallization of the amorphous phase in the structure of the coating.

Thus, the hybrid deposited (Ti,Cr)-Al-C coatings exhibit high corrosion and oxidation resistance while maintaining electrical conductivity and can be used to protect titanium alloy interconnects in lightweight MCF cells.

Acknowledgments The work was supported by the III-7-22 (0785) Project of the National Academy of Sciences of Ukraine "Development of wear-resistant electrically conductive composite materials and coatings based on MAX phases for the needs of electrical engineering, aviation, and hydrogen energy"; by the NATO project SPS G6292 “Direct liquid fuelled molten carbonate fuel cell for energy security (DIFFERENT)”, and by the MES Ukraine project №0122U001258 “Development of nanotechnological methods to prevent corrosion of structural materials in thermal and nuclear power plants”.

Many perovskites and their piezoelectric composites have been investigated for harvesting ambient mechanical energy over the past two decades; however, the prospects for their commercialization appear remote because of several practical challenges. Therefore, highly scalable supersonic cold-spraying technology was used to fabricate flexible piezoelectric films of poly(vinylidene fluoride) (PVDF) and a novel perovskite SrTiO₃ (ST). Substantial shear stress was exerted on PVDF during cold spraying owing to the hydrothermally synthesized SrTiO₃ nanocubes and supersonic velocity, and the resulting film delivered an effective piezoelectric coefficient (69.6 pm·V^-1) as confirmed by piezo-response force microscopy. As a result, the piezoelectric nanogenerator yields a maximum power of 130 µW at a load resistance of 0.9 MΩ. The composite film exhibited durability for 21,000 tapping cycles with 20 N applied force and 7 Hz frequency. The flexibility endurance was confirmed from 3000 bending cycles, and bending PENG attached to knee delivered 1 and 2.3 V on bending to 45 and 90°, respectively. After electrical poling, the PENG was subjected to a 20 N tapping force that yielded a piezopotential of 31 V. To the best of our knowledge, this is the first time piezoelectricity was obtained using an ST/PVDF composite via mechanical energy harvesting. The flexible PENG film deposited by cold-spraying shows good potential for wearable self-powered devices.

The development of acetone gas sensors for self-diagnostic and health monitoring applications has garnered significant interest in recent years [1]. Accurate sensing of acetone levels is crucial for the noninvasive diagnosis of diabetes [2]. In healthy individuals, the acetone content in the respiratory system ranges from 0.3 to 0.9 ppm, whereas individuals with diabetes exhibit acetone concentrations exceeding 1.8 ppm [3]. Among various non-invasive diagnostic techniques, chemical sensors based on semiconductor oxides have gained popularity due to their small size, low power consumption, and ease of manufacture [5–7].

SnO₂-based sensors, in particular, have been extensively researched for detecting various gases [8,9], However, achieving high sensitivity and selectivity towards trace amounts of acetone in breath remains a significant challenge. The SILAR method involves a heterogeneous interaction between the solid phase and solvated ions in the solution, creating thin films by alternately immersing the substrate into solutions containing cations and anions, followed by washing after each reaction [10].

In this study, we synthesized Fe-doped SnO₂ nanoparticles using the SILAR method to develop a selective acetone gas sensor and investigate its sensing behavior under various conditions. Uniform conditions of 100 ppm gases and 175°C were employed for all gas selectivity assessments, demonstrating the feasibility of using Fe-doped SnO₂ as a sensor for detecting volatile organic compounds, particularly acetone. The 0.5 mol.% Fe-doped SnO₂ exhibited high response and selectivity to acetone, with a fast recovery time of approximately 20 seconds. These findings suggest that Fe-doped SnO₂ sensors synthesized via the SILAR method show high selectivity to acetone vapor in an air atmosphere and rapid recovery time. Thus, doping SnO2 with Fe ions presents a promising approach for developing high-performance gas sensors selective to acetone.

Urban public transport is a vital part of urban mobility, especially in cities with a significant young population.

The appropriate public transport services should be seen from the aspect of fulfilling the passenger demands opposite the general cost, negative impacts on the transportation community as well as the externalities. Ecological transport in urban planning plays a decisive role towards creating spaces for sustainable living. Through Eco transport it is achieved the reduction in greenhouse gas emissions, improving air quality and reducing traffic congestion. 

The various current trends or developments are not always the possibility of achieving an ecological transport system for developing countries. Financial constraints can present challenges to the implementation of infrastructure projects. Therefore, in these places, improvement should be seen within the existing space of the infrastructure.

In this paper, the trip frequency of the public transport lines for a case study has been analyzed and improved through linear and non-linear programming optimization methods according to the minimization trip frequency that consequently cause fuel consumption, gas emissions while respecting the passenger demand, passenger service without significant delays, constrained number of bus fleets, and daily fuel budget.

The presence of electroactive β- and γ-phases in poly(vinylidene fluoride) (PVDF) increased by more than two folds upon supersonically spraying Sr₂SnO₄ nanorods (SSO-NRs). Shear stress between the PVDF and SSO-NRs, induced by supersonic blowing and catastrophic impact against the substrate, amplified the β- and γ-phases, which enhanced the energy-harvesting performance of a flexible piezoelectric nanogenerator (PENG). The high-aspect-ratio SSO-NRs magnified the influence of shear stress by intensifying the turbulence induced by their swirling. The supersonically driven shear stress caused multidirectional stretching, elongation, and twisting of the PVDF and transformed a large amount of the α-phase into electroactive β- and γ-phases, as evidenced by X-ray diffractometry and infrared spectroscopy. The composite film with a minimal filler content of 2.5 wt% exhibited a piezopotential of 40 V without additional poling. The optimal SSO/PVDF-based PENG delivered a high power density of 87 µW·cm⁻²_, when it was subjected to a tapping force. Furthermore, the practical applicability of the PENG was illustrated using air pressure, vibration, and human body movements. The fabricated PENG device was integrated with a supercapacitor electrode to demonstrate its wide range of applications in wearable and portable electronics.

Nanodispersed iron oxides (contained mainly magnetit) obtained by the electroerosion dispersion (EED) technology was used to produce developed by M. Monastyrov feed additive Nano-Fe+^TM. The efficiency of feed premixe Nano-Fe+^TM was studied for growing broiler chickens. The method of increasing the productivity of agricultural animals and birds is to introduce iron nanopowder into the feeding ration by spraying feed with a suspension of iron nanopowder with a particle size of 20-30 nm in doses of 0.08-0.1 mg/kg of live weight per day. At the poultry faсtory, Nano-Fe+^TM (suspension of iron oxides in glycerin) was diluted in water at a rate of 10 ml/10 l. The solution was sprayed on the feed of the birds before feeding at a rate of 10 l/1 ton of feed. The following results were obtained when using Nano-Fe+^TM: the live weight gain of chickens increased by 5÷17%; the growth rate of broilers increased by 10÷20%; the protection of poultry from diseases increased by 10÷20%; the effects of stress from vaccination, regrouping, etc. decreased. 

According to the latest definitions [1], High-Entropy Alloys (HEAs) are the alloys where the concentration of basic (at least 5) elements varies between 5-35%. The HEA has higher mixing entropy than the conventional alloys and intermetallic compounds and form the stabile solid solutions with disordered structure [1, 2, 3, 4, 5]. 

At the current stage the volume of investigations towards high entropy materials is extended from single phase solid solution structure to multi-phase structures, containing solid solution phases, intermetallic compounds, oxides, borides etc.  [6, 7, 8, 9]. 

Promised direction in this field are the high-entropy composites, prepared based on the HEAs matrix- reinforced with hard ceramic compounds. Reinforcement of HEA matrix by Intermetallic and ceramic compounds are additional tools/and challenge to improve/or design new properties of HEA based composites. Accordance evaluation “HEA is still in earlier stages hence a detailed investigation is needed” [8].  Especially, it should be underlined that HEAs, as the composite materials, are less investigated and the studies in that direction are now quite intensive. 

Accordingly, there is a huge potential to find new properties in the field of multi-component high-entropy nanostructure materials. 

The analyses show that the ball milling syntheses and adiabatic explosive compaction technologies are attractive methods for the synthesis of powdered and bulk high entropy nanocomposites [10].

In the study, mechanical alloying (MA), followed by adiabatic explosive consolidation was considered for sintering of bulk high entropy nanocomposites in Fe-W-Al-Ti-Ni–B-C system.  For MA the high energetic Planetary mill was used. The time of the processing was: 15; 30h. 36h; 48h and 72h. The ratio of balls to blend was 10:1. The phase composition and particle sizes of the powders were controlled by X-ray diffraction system and SEM. Industrial explosives, Ammonite, Powergel and Hexogen were used for adiabatic shock wave compaction of ball milled powder compositions. The MA nano blend was charged in Steel 3 alloy-tube container and at the first stage the pre-densification of the mixtures was performed by static press installation (intensity of loading P=500-1000 kg/cm²). The experiments were performed at room temperature. The shock wave pressure (loading intensity) varied in range: 3-20Gpa. The set conditions the explosive were detonated by electrical detonator. High pressure developed by explosive and temperature initiate the syntheses and consolidate the ball milled high entropy nanopowder composition. The compacting process accompanied with the syntheses and resulting in situ obtaining the bulk high entropy alloys. The phase analyses and structure-property of bulks HEA compact samples were studied. The obtained results and discussions are presented in the paper. 

Materials have always played a most important and crucial role in the development of human civilizations, throughout the Ages. So much so that they were named after them such as the stone, the bronze and the iron ages. Sustainable development is a comprehensive and complex system of systems requiring multidisciplinary and interdisciplinary science and technology inputs with economic, environmental, and social objectives and goals. In broad terms, sustainable development is achieved when the present needs and challenges are met without placing in jeopardy the ability of future generations to meet their own needs and challenges. The trade space is very wide, and the multitude of trade-offs generate considerable challenges and make it often difficult to achieve an effective balance, most beneficial to all concerned. During the last sixty years the planet’s population has grown exponentially, from 2 to almost 8 billion people, and the technological progress achieved has been tremendous, especially in the industrialized countries. These trends are expected to continue, even at faster rates. However, all these associated technological activities in the pursuit of better living standards have created a considerable depletion of resources and pollution of land, water, air, and natural resources, for the global population. During this period considerable achievements have been obtained in the development and deployment of transformative materials such as light weight metallic alloys, metal matrix composites, intermetallic and carbon fiber composites, and hybrid materials. Nano, nano-structured and nano-hybrid materials systems and nanotechnologies are now being deployed with considerable impact on energy, environment, health and sustainable development. This presentation presents perspectives on the evolution and global impact of transformative materials with a focus on Nanomaterials and Nanotechnologies, and with examples from several domains of sustainable development.

Cubic boron nitride (cBN) has long been used to create superhard tool materials [1, 2] due to its high hardness (up to 60 GPa) and chemical inertness with respect to many steels, which makes it valuable for cutting tools [3]. The most commercially known cBN-bonding systems are cBN-Al, cBN-TiC (TiCN), and cBN-Co&Al.

The main problem in high-speed machining of parts for these cutting materials is chemical wear, where temperatures in the cutting zone can reach up to 1000-1100 °C, leading to a decrease in strength and an increase in ductility of cubic boron nitride composites. One solution to this problem is to add inert components to the structure bonds, such as refractory carbides, borides, and nitrides of p- and d-elements. For cutting tools based on cubic boron nitride, the best wear resistance and service life for high-speed turning of Inconel 718 is achieved at a cBN content of 45-60% with ceramic bonds of Ti (C,N) or TiN.

Within the framework of the project "Development of the Center for Collective Use of the Institute of Materials Science of the National Academy of Sciences of Ukraine" (2023.05/0007, National Research Foundation of Ukraine), the structure and properties of superhard composite materials BL with a cBN content of 60 %, obtained in the cBN(Al)-SiB₄-WC system under high pressure and temperature, were investigated. The experiments were carried out  using the high-pressure apparatus "toroid-30".After reaching a pressure of 7.7 GPa, the composite material was sintered in the temperature range of 1600-2300 °C (time heater for 1 min). As a result, ceramic inserts, which were then ground with diamond wheels to achieve dimensions of d = 9.52 mm and h = 3.18 mm, in accordance with ISO 1832-2017 for cutting inserts - RNGN 090300T.

According to the X-ray phase analysis, the phase composition of the cBN(Al)-SiB₄-WC system composites does not change significantly with sintering temperature. The main phase is cubic boron nitride (cBN), whose lattice period varies depending on the sintering conditions. At high temperatures, rhombohedral silicon boride SiB₄ decomposes, and as a result of its interaction with tungsten carbide WC, two new phases are formed: hexagonal tungsten boride W₂B₅ (a = 0.2993(2) nm, c = 1.395(1) nm) and tetragonal tungsten silicide WSi₂ (a = 0.3208(1) nm, c = 0.7841(3) nm). An excess of boron and carbon forms micron-sized clusters of B-C compounds. Aluminum, when added in small quantities, oxidizes to α-Al₂O₃, which prevents the oxidation of other components. Thus, the material is a ceramic-matrix composite consisting of cBN, W₂B₅, WSi₂, as well as B-C and α-Al₂O₃ compounds. Electron microscopy of the obtained material at a sintering temperature of 2000 °C showed that a homogeneous porous structure was formed. The density and Young's modulus of the ceramic increase with sintering temperature and reach their maximum values at 2000 °C. A further increase in temperature leads to annealing of defects, recrystallization of the structure, and partial graphitization of cBN, which worsens the material's characteristics. The materials obtained at 1800-2000 °C have the best physical and technical characteristics and are suitable for the manufacture of cutting inserts.

Thus, ceramic-matrix composites of the cBN(Al)-SiB₄-WC system form high-strength, porous materials with high physical and mechanical characteristics. Compounds of tungsten boride and silicide, as well as aluminum oxide, provide oxidation resistance, which makes them suitable for processing high-alloy steels at high temperatures.

Closed-cell Aluminum foam is a particular type of lightweight metallic material that can sustain considerable deformation under nearly constant stress which is known as plateau stress. Thus, under dynamic loading, aluminum foams can be used for energy absorption. However, these foams have a low plateau stress and are generally unsuitable for carrying structural loads. To improve foam mechanical properties graphene reinforcement has been used to enhance its dynamic mechanical response for applications at room temperature and high temperatures. Preliminary investigation was conducted at room temperature on graphene reinforced aluminum foam by Sinha et al. [1].

For this investigation, aluminum foams reinforced with graphene concentration varying between 0.2 – 0.62 wt.%, manufactured using the liquid metallurgy route were studied. The compressive dynamic behavior of this foam has been studied over a range of high strain rates up to 2200 s^-1 using the Split Hopkinson Pressure Bar (SHPB) apparatus [2]. The mechanical response was studied at high temperatures of 473K, 623K, and compared to room temperature of 298K. Amongst the four different graphene compositions (0.20wt.%, 0.40wt.%, 0.50wt.% and 0.62 wt.%) studied, 0.62 wt.% displayed the maximum value of peak stress, plateau stress, and energy absorption. The experimental data obtained in the present study is supported using an empirical model. 

It is observed that at high temperature, the values of peak and plateau stress decreased when compared with the values obtained at room temperature for reinforced foam. However, the high strain rate response of the reinforced foam at high temperature was equal or better than the response of unreinforced foam under similar loading conditions at room temperature.

Low carbon emissions are perceived as the main target and direction in the global development. It is therefore of importance to explore new energy conversion technologies, to efficiently take advantage of the available green energy resources. Solid Oxide Cells (SOCs) are considered as one of the most promising options, since depending on the demand, they can provide both hydrogen and electricity generation in the same device. In SOCs, the main decisive factor for the efficiency is performance of the oxygen electrode, of which cobalt-containing perovskite-type materials are usually utilized due to their extraordinary electrocatalytic properties at lowered operation temperatures (500-800 °C) [1]. Meanwhile, given that the new concept of the high entropy oxides is proved to be very successful in materials science, it is of great interest to develop and study novel, multicomponent perovskites as candidate oxygen electrode materials. In fact, initial data showed promising performance, with a possibility to limit Co content [2]. Apart from the chemical content optimization, morphology of the oxygen electrode can be also enhanced, which is undoubtedly crucial to influence the oxygen reduction/evolution reaction mechanism. This can be potentially realized by the electrospinning technique, bringing new possibilities for improving the oxygen electrodes.
Taking all those concerns mentioned above into account, in this work, perovskite-type materials with varied substitution, La_0.6Sr_0.4Ni_0.15Mn_0.15Fe_0.15Cu_yCo_0.55-yO_3-δ (y = 0.05-0.20) were synthesized and characterized systematically. X-ray diffraction results confirmed that all compounds are well-crystallized, without any impurities observed, and exhibit rhombohedral symmetry (R-3c). Their structures are stable at high temperatures, up to 900 °C. Only slight variations of the oxygen content with temperature were measured, suggesting mild thermal expansion behavior. High total electrical conductivity was observed for all compounds, above 200 S cm^-1, and interestingly, a negative Seebeck coefficient was detected, suggesting that the main charge carriers are electrons (polarons). The electrochemical characterization in symmetrical cells (based on GDC solid electrolyte) showed an increased catalytic activity with the increasing Co content. However, even the relatively low Co content La_0.6Sr_0.4Ni_0.15Mn_0.15Fe_0.15Cu_0.20Co_0.35O_3-δ electrode demonstrated a desired, low polarization resistance value of only 0.018 Ω cm² at 850 °C. This could be further enhanced by over 20%, if the material was obtained by the electrospinning. The excellent performance was also proved in the full cell measurements, in which a peak power density over 1.0 W cm^-2 was reached at 850 °C, as well as a promising performance was measured in the electrolysis mode.

This work presents the encapsulation of two amino acid-based ionic liquids (AAILs), 1-Ethyl-3-methylimidazolium glycine [Emim][Gly], and 1-Ethyl-3-methylimidazolium alanine [Emim][Ala], into an highly porous metal organic framework, MOF-177, to create a state-of-the-art composite for post-combustion CO₂ capture. The AAILs@MOF-177 composite sorbents were synthesized at varying loadings of AAILs. These composite sorbents were then evaluated and examined for their thermal and structural integrity, CO₂ capture capability, CO₂/N₂ selectivity, and heat of adsorption. Thermogravimetric analysis of the composites demonstrated that the encapsulation was successful, and the slow degradation of the composites suggested that AAILs and MOF-177 interacted with each other to some extent. Both the surface area and the pore volume of the composites experienced a dramatic decrease as a direct result of the encapsulation of the AAILs. The findings of the XRD analysis also showed that an increase in the loading of AAILs greater than a particular limit produced a degradation in the structural integrity of the parent support. At pressures below 1 bar (post-combustion conditions), the AAILs encapsulated composites outperformed the pure MOF177 in terms of CO₂ uptake and selectivity. The maximum CO₂ uptake was found to be at 20 wt.% loading for both [Emim][Gly]@MOF-177 and [Emim][Ala]@MOF-177 at 0.2 bar, 303 K, and the uptake values were about three times higher than MOF-177. In addition, the CO₂/N₂ selectivity of 20-[Emim][Gly]@MOF-177 and 20-[Emim][Ala]@MOF-177 increased from 5 (pristine MOF-177) to 13 and 11, respectively. However, it was discovered that the ideal amount of AAILs was 20 wt.%, and after that, increasing the loading any further, even to 30%, did not increase the CO₂ uptake. The results of this study shed light on the stability of AAILs@MOF-177 composites, as well as their overall performance in capturing CO₂ and CO₂/N₂ selectivity under post-combustion CO₂ capture conditions.

Safeguarding wounds against secondary infections and facilitating expedited wound healing are pivotal concerns in various domains, including everyday life, clinical practice, and other contexts. Compared to traditional healing therapy, electrical stimulation therapy (ES) effectively modulates cellular behavior, promotes cell proliferation and migration, and is extensively utilized in clinical treatment. In this study, MXene, nano-chitin (Ch), and polyvinyl alcohol (PVA) multifunctional hydrogels were investigated for their exceptional mechanical properties, antibacterial activity, and biocompatibility. Leveraging the self-healing property of PVA hydrogel, a novel ring splicing dressing was designed to guide the directional electric field from the wound edge towards the wound center, thereby enhancing the endogenous electric field within the wound. Experimental results using a rat skin defect model demonstrated that the hydrogel significantly accelerated the healing process with enhanced efficiency compared to conventional dressings. This study highlights a facile approach for the preparation of MXene/Ch/PVA hydrogels with enhanced wound healing capability, while introducing novel strategies for the development of electrotherapeutic dressings through its unique ring structure design.

Materials for new energy applications have recently attracted a number of research interests due to concerns about the depletion of fossil fuels and the construction of sustainable societies. In particular, lithium and sodium ion batteries (LIBs and NIBs) with higher energy density are essential for next generation energy storage devices such as electric vehicles, hybrid electric vehicles and smart grids. A large proportion of the components of these devices are generally inorganic materials in crystalline form. Since the crystal shape, outer plane, size and crystallinity drastically affect the above properties, it is necessary to control these properties simultaneously. Nowadays, all solid-state LIBs and NIBs have attracted much interest due to a number of potential advantages, including energy densities, cost, size, safety and operating temperature. However, there are still serious problems to be solved before practical use. For example, the diffusion of lithium and sodium ions at the interface between different solid materials, including active materials and electrolytes, is still poor for charge/discharge operation in batteries.

In this context, our group has been investigating "nature-mimetic flux growth" of inorganic crystals for these applications. Flux growth is a type of liquid phase crystal growth technique in which molten metals and molten metal salts are used. Fluxes act as solvents at temperatures above their melting and/or eutectic points. As the growth conditions of inorganic crystals are similar to those found in the Earth's crust, we call it "nature-mimetic". Flux grown crystals are characterised by high quality without thermal stress, idiomorphic shape with specific crystal planes and controlled shape and size.

Recently, with the aim of achieving all-crystalline (solid state) LIBs and NIBs, we have applied the flux method to battery materials. We expected that flux crystal growth would allow (I) crystal shape control of active and solid electrolyte materials, (II) construction of good interfaces in electrodes between cathodes, solid electrolytes and anodes. The second theme would be possible if electrode materials could be dissolved and densely recrystallized on their surfaces. As a result, smooth ion transport through bulk materials and their interfaces would be realized in all-crystalline (solid) state LIBs and NIBs. Our concept using the flux method would provide a new aspect to lead an innovation in all solid state LIBs and NIBs. Details of the research progress will be presented at SIPS2024.

Acknowledgement     This research was partially supported by Council for Science, Technology and Innovation (CSTI), Cross-ministerial Strategic Innovation Promotion Program (SIP), the 3rd period of SIP, JST-GteX, Aichi Grant and JSPS Grant-in-Aid for Scientific Research (KAKENHI).

The crystalline PEO₆LiX complex features a tunnel-like polymer/salt structure that facilitates rapid lithium ion movement. However, its practical application is restricted because high ionic conductivity is only achievable with low molecular weight PEO; as the molecular weight increases, the alignment of tunnels is disrupted, resulting in reduced conductivity. High aspect ratio nanofillers derived from cellulose nanowhiskers are proposed to enhance tunnel structure formation. Compared to unfilled electrolytes, the ion conductivity at room temperature increases by up to 1100% when filled with cellulose nanowhiskers. Wide angle X-ray scattering (WAXS) reveals that adding cellulose nanowhiskers transforms the structure from an amorphous to a crystalline phase due to the enhanced crystallization driven by the interaction between the cellulose surface and polymer chains. Temperature-dependent conductivity measurements indicate that the activation energy for Li+ hopping is lower in samples filled with acidic cellulose nanowhiskers. Quasi-elastic neutron scattering (QENS) shows that the acidic surface stabilizes the rotation of PEO₆ channels, which likely accounts for the reduced activation energy and increased conductivity.

REBCO (Re=Y, Eu, Gd) coated conductors (CC) based on biaxially textured, thick and homogeneous nanoengineered multilayer structures opened up new application opportunities, such as dissipation-free energy transmission in superconducting grids, highly efficient engines for electrical aviation or compact fusion reactors beyond ITER. However, current carrying capacities of CC could be further improved because they are still far from theoretical limits. As it has been shown, one of the possible robust ways to increase current carrying capacity of CC  is overdoping with oxygen the REBCO structure of CC. 

Treatment of GdBCO_CC under 100 bar of O₂ at 600 °C for 3 h led to an increase in J_c (77K, 0 T) by 6% and a decrease in the c-parameter of Gd123 to 1.17310 nm, which may be associated not only with overdoping with oxygen, but also with silver diffusion into Gd123. No correlation was observed between J_c, T_c, c-parameter of RE123 (RE=Eu, Gd) and carrier density n_H of EuBCO_CC and GdBCO_CC treated at 300-800 ^oC, 1-160 bar O₂ for 3-12 h.

We have started investigating high oxygen pressure treatments of GdBCO and EuBCO-BHO Coated Conductors previously oxygenated with standard treatments. For our experiments we used commercially produced GdBCO and EuBCO-BHO coated conductors provided by Fujikura. The CC samples have been previously oxygenated with their standard process. For the high oxygen pressure post-treatment,  GdBCO and EuBCO-BHO coated conductors with 2 mm Ag layer on the surface of GdBCO CC and without and with Ag layer on the surface of  EuBCO-BHO CC were used. Therefore, before experiments the upper Cu layer (and in some cases the Ag layer) was chemically removed from CCs tapes. In the case of EuBCO-BHO_CCs  the Ag upper layer was removed chemically as well, but for some experiments it was preserved as indicated. The architecture (from  top) of the studied CCs was as follows: (1) FYSC : Ag (2μm)/ GdBCO (1.8μm)/ CeO₂ (700 nm)/ MgO/ / Al₂O₃/Y₂O₃ /Hastelloy (75 μm); (2) FESC : EuBCO (2.5μm)+BHO Nanorods/ CeO₂ (700 nm)/ /MgO/ Al₂O₃/Y₂O₃ / Hastelloy (50 μm); (3) Ag (2μm)/ EuBCO (2.5μm)+BHO Nanorods/ CeO₂ (700 nm)MgO/ / Al₂O₃/Y₂O₃/ Hastelloy (50 μm).

A specially designed tube furnace was used for the oxygenation process. The oxygen pressure in the furnace varied from 1 to 160 bar, the temperature from 300 to 800 °C, and the heating rate was 5 ºC/min. After, a dwell of temperature for a certain time held at the required pressure was attained, and afterwards the heater was turned off.

Results on critical current density, superconducting transition temperature, charge carrier densities, c-lattice parameter and Auger, indicate that high oxygen pressures of 100 and 160 bar can be sustained by these materials when high temperatures are used and that this can be a route to overdope these Coated Conductors. Furthermore, we evidence that these post oxygen treatements should be done without Ag etching so that the REBCO material is not exposed to air during the high pressure treatments. Futher work is on-going to obtain the best conditions to increase the charge carrier concentration and consequently the criticial current density in a robust way.

AcknowledgementS: We acknowledge funds from MUGSUP, UCRAN20088 project from CSIC programme from the scientific cooperation with Ukraine, the Spanish Ministry of Science and Innovation and the European Regional Development Fund, MCIU/AEI/FEDER for SUPERENERTECH (PID2021-127297OB-C21), FUNFUTURE “Severo Ochoa” Program for Centers of Excellence in R&D (CEX2019-000917-S), and HTS-JOINTS (PDC2022-133208-I00),  NAS of Ukraine Project III-7-24 (0788)  Authors also thanks Fujikura for supplying the samples

The Nickel-Titanium (NiTi) alloy belongs to the group of smart materials, standing out for its excellent shape memory properties, superelasticity, damping, and biocompatibility. This alloy is used in both technological fields and, more importantly, in medical and dental areas. The use of powder metallurgy processes in the production of titanium alloy products is justified by its economic advantages, such as high raw material utilization, low energy transformation compared to fusion processes, excellent dimensional tolerance, allowing for various combinations and control of chemical elements (alloys). Therefore, powder metallurgy becomes an interesting process in the development of new materials, with a tendency to reduce the manufacturing costs of Ni-Ti alloys, achieving mechanical properties similar to human bone.This study proposes a microstructural analysis and an examination of the physical and mechanical properties of the NiTi alloy processed via powder metallurgy, combining temperature and time to produce a material suitable for biocompatibility feasibility testing in the human body.The alloy sintering was conducted over 24, 36, and 48 hours at a temperature of 932°C without the presence of the liquid phase. This study includes characterization techniques for mechanical properties using Vickers microhardness, and metallographic analysis using Optical Microscopy (OM) and Scanning Electron Microscopy (SEM).It was observed that with increased sintering time: porosity decreased, resulting in volumetric shrinkage and increased density. Thus, sintering for 36 hours proved to be the most ideal, potentially resulting in an alloy with the best shape memory effect properties.

Arsenic contamination of groundwater and soil remains a significant global health concern, affecting millions of people worldwide. The primary source of arsenic exposure is contaminated drinking water, with inorganic arsenic being the most toxic form. Recent research has highlighted the long-term health effects of chronic arsenic exposure, including increased risks of cancer, cardiovascular diseases, and metabolic disorders such as diabetes. Current trends in arsenic research focus on understanding the mechanisms of toxicity, differential susceptibility, and the development of effective remediation strategies. Epigenetic alterations, omics analyses, and the study of arsenic metabolism have emerged as key areas of investigation. Notably, even low-to-moderate levels of arsenic exposure have been associated with adverse health outcomes, suggesting that current guidelines for maximum permissible limits may need reevaluation. Nano-remediation strategies have gained significant attention as promising solutions for arsenic contamination. These approaches leverage the unique properties of nanomaterials, such as high surface area and reactivity, to effectively remove arsenic from water and soil. Common nano-remediation techniques include the use of iron-based nanoparticles, carbon nanotubes, and metal oxide nanocomposites. These materials can adsorb, reduce, or oxidize arsenic species, facilitating their removal from contaminated media. Recent advancements in nano-remediation have focused on improving the efficiency, selectivity, and sustainability of these technologies. Researchers are developing novel nanocomposites with enhanced arsenic removal capacity, exploring green synthesis methods for nanoparticles, and investigating the potential of biogenic nanomaterials. Additionally, efforts are being made to address challenges associated with the scalability and environmental impact of nano-remediation techniques. In conclusion, while arsenic toxicity remains a significant public health issue, ongoing research into its sources, health effects, and remediation strategies offers promising avenues for mitigation. Nano-remediation technologies show great potential for effective arsenic removal, though further research is needed to optimize their performance and ensure their safe implementation in real-world settings.

Tissue wounds afflict millions of individuals annually, giving rise to significant social and economic concerns. Previous investigations have demonstrated the remarkable potential of hydrogels in wound healing owing to their exceptional capabilities in absorbing wound exudate, moisturizing, facilitating oxygen permeation, and possessing a three-dimensional porous structure[1]. However, natural polymer-based hydrogel dressings for wounds often suffer from susceptibility to bacterial growth and subsequent infection, which represents a major obstacle impeding the wound healing process.
Photothermal therapy (PTT) is a strategy to achieve antibacterial effect through rapid hyperthermia produced by a photothermal agent under near-infrared (NIR) light radiation (700-1100 nm). Compared with conventional antibacterial methods, PTT offers distinct advantages including heightened sterilization potency, reduced treatment duration, and diminished risk of drug-resistant bacteria[2]. We previously synthesized stable tricomplex molecules (PA@Fe) assembled by protocatechualdehyde (PA) and ferric iron, which were subsequently embedded in a gelatin hydrogel (Gel-PA@Fe). The embedded PA@Fe served as a crosslinker to improve the mechanical and adhesive properties of hydrogels through coordination bonds and dynamic Schiff base bonds, meanwhile acting as a photothermal agent to convert NIR light into heart to kill bacteria effectively[3]. The hydrogel was endowed with exceptional hemostatic and antioxidant properties by grafting serotonin onto the gelatin molecular chain, resulting in the preparation of a composite hydrogel (GelS-PA@Fe). As a mediator of blood coagulation, serotonin can interact with catechol-containing PA and chemical hemostatic agents, thereby enhancing the adhesion of more blood cells to the hydrogel surface. The free radical scavenging rate of GelS-PA@Fe (80.49%) exhibited a 1.5-fold increase compared to that of the Gel-PA@Fe hydrogel, indicating enhanced efficacy in neutralizing free radicals. Importantly, the introduction of serotonin did not compromise the biocompatibility and photothermal antibacterial properties of the GelS-PA@Fe hydrogel. Our results indicated the great potential of GelS-PA@Fe hydrogel in promoting infected wound healing.

Ultra-high temperature (UHTC) transition metal borides can be used for a wide range of mechanical applications - as components of military and commercial equipment operating in extreme conditions, for rocket propulsion, hypersonic flights, atmospheric reentry, protective coatings on graphite, for using in abrasive, erosive, corrosive and high-temperature environments, which requires materials with significantly improved physical properties. To UHTC belongs TaB₂ which exhibits high melting point (3200 °C), hardness (24.5 GPa -25.6 GPa), fracture toughness (4.5 MPa m^0.5), bending strength (555 MPa), excellent chemical stability, electrical (308×10⁴  Ω^-1×ｍ^-1)  and thermal (0.160 -0.161 W×cm^-1×K^-1 at 300-1300 ^oC) conductivity, good corrosion resistance [1-5]. To increase the oxidation resistance and mechanical characteristics TaB₂ can be modified by silicides [1]. In the present study we investigated modification of TaB₂ by MoSi₂, ZrSi₂ and Si₃N₄ in the amount of 20-30 wt.% and its sintering process under hot pressing conditions (30 MPa, 1750-1950 ^oC) and high pressure (4.1 GPa) - high temperature (1800 ^oC) conditions. The highest Vickers hardness H_V=31.5 GPa and fracture toughness K_1C=6 MPa×m^0.5 under P= 9.8 N load was obtained for the composite sintered at 30 MPа, 1750 °C, 20 min from TaB₂+20 wt.% ZrSi₂, the increase of amount of ZrSi₂ up to 30 wt.% leads to further increase in K_1C= 6.9 MPa×m^0.5, but to the reduction of microhardness  down to H_V=23.5 GPa. The composite sintered under 30 GPa at 1950 °C for 40 min from TaB₂+20 wt.% MoSi₂ showed H_V=28.2 GPa and K_1C= 5.42 MPa×m^0.5. TaB₂+30 wt.% Si₃N₄ sintered at 4.1 GPa, 1800 ^oC for 7 min had H_V=18.8 GPa and K_1C= 4.82 MPa×m^0.5. The specific weight of the materials prepared from TaB₂+20 wt.% MoSi₂ was g=10.82 g/cm³, TaB₂+30 wt.% Si₃N₄ - g=8.77 g/cm³, TaB₂+20 wt.% ZrSi₂ - g=9.35 g/cm³, TaB₂+30 wt.% ZrSi₂ - g=10.12 g/cm³.

AcknowledgementS: This work was supported by the Project of the National Academy of Sciences of Ukraine III-5-23 (0786) “Study of regularities and optimization of sintering parameters of composite materials based on refractory borides and carbides, their physical and mechanical properties in order to obtain products of complex shape for high-temperature equipment with an operating temperature of up to 2000 ^oC”

In the electrodynamic properties study of new AlN- 5wt.%C(diamond powder)-5wt.%Mo composite materials the values ​​and   behavior of the real and imaginary parts of the microwave permittivity were determined and the optimal technological process for materials synthesis was established. The materials with density 3.16 g/cm³ and 3.30 g/cm³ were obtained by the pressureless sintering (PS) at the temperature of 1850 °C and by the hot pressing (HP) at the temperature of 1820 °C (pressure of 15 MPa), respectively.            

The microstructure and phase composition of the composite materials were studied using a scanning electron microscope and the X-ray diffractometer Ultima IV (Rigaku, Japan)  ​​with the Rietveld method for data analysis. The imaginary and real parts of the permittivity were measured by the microwave vector network analyzer Keysight PNA N5227A in the frequency range of 26 - 40 GHz.

The results of structural studies showed that sintering of composites by different methods results in  almost unchanged their phase composition, and the main phases are AlN, Al₃(O,N)₄, Mo₂C, Y₃Al₅O₁₂, and C (graphite) - as in [1].

It was determined that the real part of the permittivity (ε') for both composites obtained by the PS and HP methods is practically frequency independent between 26 to 36 GHz with the value of about 8 and 27 , respectively. At  the same time, the imaginary part of the permittivity (ε″) increases from 0.29 to 1 and from 3.46 to 5.56 for materials made by the PS and HP methods, respectively. When the test frequency is increased from 36 to 40 GHz, significant fluctuations in the permittivity values ​​ are observed, which is possibly related to the greater intensity of electromagnetic wave internal reflections due to the peculiarities of the formation of the materials structure.

As a result of the research, it was established that composite materials obtained by the hot pressing method are characterized by higher density and higher values ​​of the real part of the permittivity in the frequency range 26 - 36 GHz.

During the processing of polymetallic ores, a large amount of waste is formed containing heavy metal sulphides, which, as a result of natural leaching, enter the mine and mine wastewater, polluting the environment. The toxic effect of heavy metals on living organisms leads to disruption of enzymatic reactions .

This work is devoted to the study of the possibility of electrolytic purification of wastewater, primarily from copper (II) ions, which are characterized by high toxicity and are one of the main sources of pollution of the hydrosphere. The electrolysis method ensures minimal costs for their further processing and creates the possibility of implementing resource-saving and low-waste processes.

However, the difficulties of cleaning dilute solutions from heavy metal ions by means of electrodeposition are associated with the low speed of the process and the presence of side reactions. Therefore, the development of the method and the creation of effective designs of industrial devices that allow the intensification of the electrolysis process open up the prospect of using the method to extract metals from dilute solutions.

To extract copper with a high degree and high current yield from dilute solutions, we have developed a special design of an reactor with a high hydrodynamic regime [1].

In the reactorr, the radially arranged electrodes have the shape of a Leprechaun. In the center of the electrolyzer, there is a mechanical stirrer of an original shape, which directs the flow of liquid between the electrodes with a strong centrifugal force. The shape of the electrodes maintains the flow of liquid in a circular motion along the wall of the cylindrical reactor. The reactor operates on the hydrocyclone principle and the flow of liquid moving at high speed along the electrodes removes the cathode product, which, after passing through the corresponding windows of the reactor, is collected at the bottom of the conical body (collector), from where it is periodically unloaded. The reactor achieved a significant improvement in the intensity of forced convection and a solution to the problem of removing copper powder from flat stainless steel cathodes.

Large-scale laboratory tests have shown that a cascade arrangement of two such reactors, one of which operates at high current values ​​(I-15A, Cu-1.08g/l, Q-85.2%, ɳ-62.1%, W-3800 kW∙hour/t), and the other at lower ones (I-4.0A, , Cu-0.16g/l, Q-68.6%, ɳ-27.5%, W-7339 kW∙hour/t), allows a total extraction of up to 95.4% of copper from quarry water with a current efficiency of 54.9% with a residual copper concentration in the solution of 0.05 g/l and a specific energy consumption of 4175 kW∙hour/t, which corresponds to 5-10% of the cost of copper.

As the research results showed, the bottleneck in the design of the above reactor with flat steel electrodes is the process of extracting copper with a concentration of Cu≤0.16 g/l (second reactor).

In order to intensify the reactor process at very low copper concentrations  in solution Cu≤0.16 g/l, we designed a new electrochemical reactor, in the center of which a volumetric-porous flow-through cathode block with a mechanical stirrer is located [2]. The cathode block consists of perforated cylindrical graphite on which a carbon material with high physical, chemical and operational properties is wrapped along its entire height. The mechanical stirrer facilitates the free passage of liquid through the pores of the carbon-graphite material, thereby reducing the hydrodynamic resistance of the solution flow and increasing the rate of metal deposition by reducing the cathodic polarization in the thickness of the carbon material.

It has been experimentally established that when using an electrolyzer with flat steel cathodes from dilute solutions (Cu≤0.16 g/l), copper extraction in 1 hour is 19.6% with an extraction rate of 2.22 g/h˖m2, while in an electrolyzer with cathodes made of carbon-graphite materials, all other things being equal, it is 83-84% with an extraction rate of 15.1 g/h˖m2, as a result of which the intensity of the process increases by 6.8 times. 

It is important to note that electrolytic copper can be extracted from the surface of a carbonaceous material by repeated chemical or electrochemical regeneration without changing its electrode properties.

Highly flexible and conductive carbon nanofibers (CNFs) embedded with pseudocapacitive iron–vanadium oxide (FVO) were fabricated via electrospinning followed by high-temperature annealing (900 °C). CNFs have a graphitic structure with minimal defects, which could hinder the access of electrolytic ions to multivalent FVO. Therefore, a sacrificial polymer, such as poly(methyl methacrylate) (PMMA), was introduced to enhance the electrolytic ion pathways by altering the internal structure of nanofiber. In addition, terephthalic acid was added to a polyacrylonitrile–PMMA solution to facilitate flexibility by increasing the cross-linking of the electrospun fibers. The fabricated flexible FVO/CNFs exhibited significantly enhanced electrochemical performance. The optimal sample had a high areal capacitance of 1058 mF·cm⁻² at a current density of 2.5 mA·cm^-2 and showed 100% capacitance retention during long-term cycling (10,000 cycles). The capacitance retention decreased to 81.3% when the current density was increased to 25 mA·cm^-2. The wider potential window of 0–1.6 V increased the energy density to 389 µW·h·cm^-2. The optimal FVO/CNF sample maintained 90% capacitance retention after 200 bending cycles.

The proper utilization and upcycling of plastic waste are essential for mitigating environmental damage, optimizing resource use, and advancing a circular economy [1]. Phosphorus doping of carbon materials introduces a high density of phosphorus-containing active groups and expands interlayer distances, which significantly boosts the electrochemical performance of the anode material [2].

In this study, we upcycled waste PET into phosphorus-doped hard carbon (P-HC) through a single-step pyrolysis process with orthophosphoric acid (H₃PO₄), aiming to enhance the electrochemical properties of the resultant carbon. The synthesized P-HC was characterized using Fourier-transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA-DSC), X-ray diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM) to elucidate its structural and thermal properties.

Electrochemical characterizations revealed that the P-HC anodes exhibit superior lithium storage capabilities, including high specific capacity and excellent rate capability (492 mAhg^-1 at 0.1 Ag^-1 and 131 mAhg^-1 at 3.5 Ag^-1, respectively), significantly outperforming non-doped PET-derived carbon. This enhancement is attributed to the improved electrical conductivity and structural stability imparted by phosphorus doping [3]. The P-HC anodes retained a high specific capacity after numerous cycles, demonstrating their potential for long-term application in LIBs.

This study presents a dual solution to plastic pollution and energy storage challenges by converting PET waste into high-performance anode materials for next-generation LIBs. This sustainable approach not only mitigates environmental impact but also contributes to the advancement of energy storage technologies.