Delamination Method Research Articles

Balancing Surface Chemistry and Flake Size of MXene-Based Electrodes for Bioelectrochemical Reactors.

MXenes have excellent properties as electrode materials in energy storage devices or fuel cells. In bioelectrochemical systems (for wastewater treatment and energy harvesting), MXenes can have antimicrobial characteristics in some conditions. Here, different intercalation and delamination approaches to obtain Ti3C2Tx MXene flakes with different terminal groups and lateral dimensions are comprehensively investigated. The effect of these properties on the energy harvesting performance from wastewater is then assessed. Regardless of the utilized intercalant molecules, MXene flakes obtained using soft delamination approaches are much larger (up to 10µm) than those obtained using mechanical delamination methods (<1.5nm), with a relatively higher content of ─O/─OH surface terminations. When employed in microbial fuel cells, electrodes made of these large MXene flakes have demonstrated a power density of over 400% higher than smaller MXene flakes, thanks to their lower charge transfer resistance (0.38Ω). These findings highlight the crucial role of selecting appropriate intercalation and delamination methods when synthesizing MXenes for bioelectrochemical applications.

MXene/Bacterial Cellulose Hybrid Materials for Sustainable Soft Electronics.

This work evaluated bacterial cellulose (BC) as a possible biodegradable soft electronics substrate in comparison to polyethylene terephthalate (PET), while also focusing on evaluating hybrid MXene/BC material as potential flexible electronic sensor. Material characterization studies revealed that the BC material structure consists of nanofibers with diameters ranging from 70 to 140 nm, stacked layer-by-layer. BC samples produced are sensitive to post-treatment with isopropanol resulting in a change of structural and mechanical properties. The viscoelastic properties of the BC substrates have been studied experimentally in comparison with the PET film. Aged BC substrate showcased similar viscoelastic properties stability, while exhibiting better properties above 70 °C, with total storage modulus change of -15% and loss modulus change of 21%. MXenes prepared using the Minimally Intensive Layer Delamination (MILD) method were screen-printed onto BC substrates and PET films to form MXene/BC (MX/BC) and MXene/PET (MX/PET) devices. The electrical properties results showcased different resistive behavior on both BC and PET substrate samples with different impedance moduli. MX/PET presented lower sheet resistance of around 156 Ω·sq-1, while MX/BC was 2733 Ω·sq-1. Finally, the MX/BC and MX/PET devices were subjected to repeatable quasi-static load tests and the piezoresistive sensing behavior of the devices has been reported.

Detection of delamination using laser-generated Lamb waves with improved wavenumber analysis

Abstract Delamination is a typical failure mode in multilayered materials, which may potentially threaten the safety and reliability of the materials if not detected promptly. This paper proposes a novel quantitative detection method for delamination in multilayered materials based on laser-generated Lamb waves with improved wavenumber analysis. First, a three-dimensional(3D) finite element model is established to simulate the interaction between delamination and laser-generated Lamb waves. The propagation characteristics of Lamb waves in multilayered materials without defects and with delamination of three different shapes, i.e., rectangular, circular and triangular are analyzed. And the mechanism that delamination can lead to the appearance of scattered wave and new wavenumber components is investigated, facilitating the quantitative detection of delamination. Then, an improved wavenumber analysis method for quantitative detection of delamination is proposed. The new wavenumber components caused by delamination are extracted by broadband adaptive wavenumber filtering to reduce imaging interference and artifacts caused by irrelevant components, and the spatial wavenumber spectrum is obtained by fast broadband local wavenumber estimation algorithm to enhance the delamination imaging accuracy and spatial resolution. The experimental results indicate that, across various experimental scenarios, the proposed method achieves superior imaging precision compared to traditional wavenumber filtering or local wavenumber estimation methods, and can quantitatively identify delamination defects of various shapes and sizes.

Exploring the molarity of Lithium Fluoride in minimally intensive layer delamination (MILD) method for efficient room temperature synthesis of high quality Ti3C2Tx free-standing film

In recent years, MXene has become the most demanding material in the 2D family, leading to their increased use in research for a diverse range of applications, such as energy storage, water purification, optoelectronics, electromagnetic interference (EMI) shielding and medicine. However, recent research has made it increasingly important to synthesize high-quality MXene in a safe, reliable, fast, reproducible, and good-yielding single-step method. To achieve high-quality MXene by etching the MAX phase precursors, it is very important to critically optimize synthesis parameters, such as etching method, etchant concentrations, temperature, time, etc. Minimally intensive layer delamination (MILD) method for MXene synthesis using Lithium Fluoride (LiF) salt and hydrochloric (HCl) acid seems to be a better choice in the context of improved performance in different applications as well as its scalability and reproducibility. Here, the molar ratio of HCL/LIF is critical for Aluminium etching at room temperature to produce a high-quality MXene with = O, -OH, -F termination groups in the MILD method. However, in case of MILD method the effect of LiF/HCL concentrations on quality of MXene need to be addressed. In this study, we focus on room temperature etching of Ti3AlC2 using MILD method to synthesize quasi two-dimensional carbide (Ti3C2) MXene. The influence of molarity concentration of etchants (LiF and HCl) on quality of MXene has been thoroughly investigated. Different molar concentrations of Lithium Fluoride (LiF) with fixed HCL concentration were tested at room temperature for 24 h in the etching process. The crystal structure, microstructure and composition of the MXene were characterized using X-ray diffraction, Raman spectroscopy, and electron microscopy. Flexible free-standing MXene film with largest shift in the characteristic (002) peak, indicating large interplanar spacing, has been successfully achieved repeatedly for an optimum molar concentration of etchants at room temperature.

Optimization of Synthesizing Conditions for MXene (Ti3C2) Photocatalyst: Effect of LiF:Ti3AlC2 Mass Ratio

The analysis of the proposed work, specifically the development of the MXene photocatalyst, will be described in this chapter. The results of the analysis are useful for comparing the pristine precursor and etched structures of the MXene photocatalyst. A minimally intensive layer delamination (MILD) method will be used to create the MXene photocatalyst which uses lower fluorine content solution (HCl-LiF) creating a safer and easier method. The synthesis parameters for the development of highly efficient MXene photocatalysts, such as LiF:Ti3AlC2 mass ratio will be optimized. FTIR, XRD, SAP, FESEM and DR UV-Vis analysis will be used to characterize the as-developed MXene photocatalyst and its precursor, Ti3AlC2. The hypothesis of this study is etching treatment will increase the hydrophilicity and active functional group such as oxygen (O), fluorine (F) and hydroxyl (-OH) on MXene surfaces. The performance of photocatalytic degradation will be tested with an initial dye concentration of 30 ppm, solution pH at pH7 at room temperature (±27 ̊C). Each photocatalytic degradation study was performed in 50 ml of methylene blue solution with 0.1 g photocatalyst. All developed MXenes will undergo photocatalytic degradation performance to identify the optimized synthesizing conditions. The highest MXene photodegradation performance was found to reach 90% removal within 180 min.

Local thermal resistance delamination method for precise analysis and optimization of heat transfer processes

Excessive carbon emissions are one of the global challenges. Promoting the optimization of high-efficiency heat transfer systems and improving the analysis and evaluation methods of heat exchangers is one of the effective ways to save energy and reduce carbon emissions. The traditional thermal resistance analysis method treats the fluid domain as a uniform whole, which makes it difficult to regulate the heat transfer characteristics in local regions, especially in the near-wall region. To address this problem, this paper obtained the thermal resistance mathematical equation for different regions in the flow field by magnitude analysis. The thermal resistance delamination method for dividing the thermal resistance field is proposed from the channel flow, and the conduction, mixing and advection zones in the flow field are identified. The delamination factor (α) is defined to determine the boundaries of thermal resistance zones. The α values which meet the delamination factor independence under forced convection and natural convection conditions are investigated. By studying the mechanism of the thermal resistance in conduction zone of the enhanced heat transfer structure, the critical value of fin height to achieve maximum enhancement efficiency is determined. The thermal resistance delamination facilitates a comprehensive analysis of heat transfer processes and structure optimization in the near-wall region.

NiFe layered double hydroxide nanosheets self assembled and etched by phosphotungstic acid for the enhanced oxygen evolution reaction

Poor conductivity and low reaction kinetics of layered double hydroxides (LDHs) hindered their large-scale applications as catalysts in the oxygen evolution reactions (OER). The composites with vacancies, high valence cations and 3D gradient pore structures were synthesized by the ionic exchange, delamination and self-assembly methods. The nanoclusters [PW12O40]3- were successfully intercalated into the interlayers of LDHs due to the static attraction. Meanwhile, the partial metal cations in the layers were etched by its conjugate acid. The molar ratios of Ni:Fe and acid:LDH need to be modulated to achieve the optimum catalytic performances. The composite 1:4PW12–Ni3Fe exhibited a lower overpotential 270 mV at 10 mA cm−2, superior kinetics (43 mV dec−1), better conductivity (2.68 Ω cm−2) and larger turnover frequency (3.59 s−1) than the bulk and nanosheet counterparts with reevesite-like structure. [PW12O40]3- more effectively reduced the overpotentials of LDHs than other interlayer anions (e.g.WO4−, B4O72− and CnH2n+1SO42−). The favourable electrocatalytic performances were attributed to the synergistic effects. The vacancies provided new active centers with high intermediate adsorption energy. The high valances cations induced electronic coupling and spatial charge redistribution. 3D gradient pore structures with a large electrochemical active surface area exposed active sites and provided a convenient path for transferring masses and charges.

Freeze-sonication delamination method of high crystalline-quality MXene with high yield

MXene has attracted broad attention for its unique physicochemical properties and has flourished in many research areas. Since MXene obtained by high crystalline-quality MAX phase has excellent stability and properties, the etching of high crystalline-quality MAX phase and delamination into monolayer will become an inevitable trend. However, the delamination of the high crystalline-quality MXene is significantly more challenging than conventional MXene because of the more vital van der Waals forces of the more regular interlayer structure. Here, we propose a freeze-sonication delamination (FSD) strategy that can solve the difficult problem of efficiently exfoliation of high crystalline-quality MXene. The principle is to utilize the synergistic effect of ultrasound and ionic intercalation to allow a large number of water molecules to penetrate into the interlayer, which results in volume expansion, and then ultrasound to obtain monolayer MXene in a frozen state. This method not only increases the yield of high crystalline-quality monolayer MXene but also prevents the size reduction and the nanosheet destruction. The yield of monolayer MXene reached 74.2 % with a concentration of 19.8 mg/mL after six FSD cycles (the time of ultrasound treatment is 5 min after per freeze). Meanwhile, under the protection of ice, the obtained monolayer MXene has a larger size with more complete nanosheets than ultrasound-delaminated MXene. Supercapacitors made of high crystalline-quality MXene exhibits excellent gravimetric capacitance of 261.1 F/g and satisfactory cycling stability.

Enhanced osteogenic and ROS-scavenging MXene nanosheets incorporated gelatin-based nanocomposite hydrogels for critical-sized calvarial defect repair

The healing of critical-sized bone defects is a major challenge in the field of bone tissue engineering. Gelatin-related hydrogels have emerged as a potential solution due to their desirable properties. However, their limited osteogenic, mechanical, and reactive oxygen species (ROS)-scavenging capabilities have hindered their clinical application. To overcome this issue, we developed a biofunctional gelatin-Mxene nanocomposite hydrogel. Firstly, we prepared two-dimensional (2D) Ti3C2 MXene nanosheets using a layer delamination method. Secondly, these nanosheets were incorporated into a transglutaminase (TG) enzyme-containing gallic acid-imbedded gelatin (GGA) pre-gel solution to create an injectable GGA-MXene (GM) nanocomposite hydrogel. The GM hydrogels exhibited superior compressive strength (44–75.6 kPa) and modulus (24–44.5 kPa) compared to the GGA hydrogels. Additionally, the GM hydrogel demonstrated the ability to scavenge reactive oxygen species (OH- and DPPH radicals), protecting MC3T3-E1 cells from oxidative stress. GM hydrogels were non-toxic to MC3T3-E1 cells, increased alkaline phosphatase secretion, calcium nodule formation, and upregulated osteogenic gene expressions (ALP, OCN, and RUNX2). The GM400 hydrogel was implanted in critical-sized calvarial defects in rats. Remarkably, it exhibited significant potential for promoting new bone formation. These findings indicated that GM hydrogel could be a viable candidate for future clinical applications in the treatment of critical-sized bone defects.

Ti3C2Tx Electromagnetic Shielding Performance: Investigating Environmental Influences and Structural Changes

AbstractMXenes, a promising family of 2D transition metal carbides/nitrides, are renowned for their exceptional electronic conductivity and mechanical stability, establishing them as highly desirable candidates for advanced electromagnetic interference (EMI) shielding material. Despite these advantages, challenges persist in optimizing MXene synthesis methods and improving their oxidation resistance. Surface defects on MXenes significantly impact their electronic properties, impeding charge transport and catalyzing the oxidation process. In this study, a novel synthesis protocol derived from the conventional, minimally invasive layer delamination (MILD) method, is presented. Two additional steps are introduced aiming at enhancing process yield, addressing a crucial issue as conventional methods often yield high‐quality individual MXene flakes but struggle to generate sufficient quantities for bulk material production. This approach successfully yields Ti3C2Tx films with excellent conductivity (3973.72 ±121.31 Scm−1) and an average EMI shielding effectiveness (SE) of 56.09 ± 1.60 dB within the 1.5 to 10 GHz frequency range at 35% relative humidity (RH). Furthermore, this investigation delves into the long‐term oxidation stability of these films under varying RH conditions. These findings underscore the effectiveness of this innovative synthesis approach in elevating both the conductivity and EMI shielding capabilities of MXene materials. This advancement represents a significant step toward harnessing MXenes for practical applications requiring robust EMI shielding solutions. Additionally, insights into long‐term stability offer critical considerations for implementing MXenes in real‐world environments.

Comprehensive study on catalytic potential of Ti3C2Tx based catalyzer for Dye sensitized solar cells application

Abstract Recently Dye-sensitized solar cells (DSSC) have gained significant research limelight for having exceptional photovoltaic potential. However, DSSC became an underdog solar cell due to the use of an expensive transparent conductive layer (FTO/ITO) along with the use of rare earth element Pt to concoct counter electrode (CE). Thus, an attempt has been made to concoct a Ti3C2-TX MXene-based CE to replace both the transparent conductive layer and CE. Herein, relatively larger with less defective Ti3C2 flakes were produced by the minimally intensive layer delamination method, and physical architecture was investigated by X-ray diffraction (XRD) mapping, Field-emission scanning electron microscope (FE-SEM) and Dynamic light scattering (DLS), respectively. MXene flakes were drop cast on a glass substrate by dispersing it in ethanol, isopropyl alcohol, and deionized water, respectively, and found the least sheet resistance, 14.824 Ω/sq by 4-point probe test, owing to superior adsorption force with the glass substrate. Ethanol solvent facilitates optimum interlamellar spacing to promote fast diffusion and transportation. Further, the study was expanded by introducing it to numerous sintering temperatures to find the best result. The result revealed exceptional sheet resistance of 0.08 Ω/sq for the 120℃ sintered sample, which was encouraged by removing water intercalant and occupying H+. Further, the potential of MXene-based counter electrode’s catalytic activity has been studied through electrochemical impedance spectroscopy, Tafel polarization, and Cyclic voltammogram under iodide and triiodide-based electrolytes. The electrochemical study revealed 120℃ sintered sample superior to 140℃ sintered but comparable to Pt CE. 120℃ sintered Ti3C2-based CE performed exceptional 6.27% power conversion efficiency. Thus, this novel study communicates that Ti3C2-TX is a potential replacement for transparent conductive oxide layer and Pt, frequently used in Dye-sensitized solar cell applications.

Delamination Techniques of Waste Solar Panels: A Review

Solar panels are an environmentally friendly alternative to fossil fuels; however, their useful life is limited to approximately 25 years, after which they become a waste management issue. Proper management and recycling of end-of-life (EOL) solar panels are paramount. It protects the environment because of the high energy consumption of silicon production. We can effectively decrease energy and cost requirements by recovering silicon from recycled solar panels. This is one-third of those needed for manufacturing silicon directly. Moreover, solar panels include heavy metals, such as lead, tin, and cadmium, which pose risks to human health and the environment. Empirical evidence suggests that the costs of mining materials can exceed those of recycled materials, thereby making recycling a more cost-effective means of resource harvesting. This review paper focuses on the techniques developed to delaminate solar panels, which are considered a crucial step in the recycling of EOL solar panels. Initially, various classifications of solar panels are given. Subsequently, an analysis of the diverse methods of solar panel delamination and their efficacy in the retrieval of valued materials is presented. This investigation has identified three primary modes of delamination, namely mechanical, thermal, and chemical. Among these, mechanical delamination is deemed to be a sustainable and cost-effective option when compared to thermal and chemical delamination. The current most popular method of thermal delamination is characterized by its high energy consumption and potential emission, and the chemical delamination generates hazardous liquids that pose their own threat to the environment. This study emphasizes the mechanical delamination techniques, characterized by their environmentally friendly nature, minimal ecological footprint, and capacity to retrieve entire glass panels intact. This paper also discusses the current gaps and potential enhancements for mechanical delamination techniques. For example, some delamination techniques result in crushed materials. Thus, the handling and recovery of materials such as glass and silicon cells require the implementation of an appropriate sorting technique. Also, the value obtained from recovering crushed materials is lower than that of intact glass and silicon cells.

Degradation of cathode in air and its influences on direct recycling

Delamination has been widely used in direct recycling of spent lithium-ion batteries (LIBs) as the first step to harvest cathode materials from cathodes. The variations of the recycling performance have been documented in many studies. The main mechanism of delamination is the inactivation of bonding forces provided by the polyvinylidene fluoride (PVDF) binder. It is believed that the storage environment (air exposure time) will affect the performances of delamination to some extent. Three representative methods (direct calcination, pressure washing, and NMP solvent extraction) for delamination were studied to elucidate the effect of air exposure time on delamination efficiency. The peel-off efficiency (98–99%) of the direct calcination method was barely influenced by air exposure time. The pressure washing system or NMP solvent extraction method also exhibited high peel-off efficiency using samples after a long air exposure time (1 month), however these methods may have problems regarding Al contamination, i.e., 11.5 mg/g of pressure washing system and 134.4 mg/g of NMP solvent extraction. Results suggest that enhanced adhesion (0.11 MPa/month) could be a potential reason why air contact time affects delamination, with O2 and/or H2O acting as contributors. This finding may help to maximum performance of delamination, as it highlights the importance of storage conditions of the spent LIBs prior to direct recycling.

High-yield and high-throughput delamination of multilayer MXene via high-pressure homogenization

Two-dimensional (2D) MXenes are a large family of materials with unique properties and numerous potential applications. They are typically produced by selective chemical etching of MAX phase precursors, which is a top-down approach allowing for scalable manufacturing. Multilayer MXenes are then further processed by chemical intercalation and delamination to produce a stable dispersion of 2D flakes in water. The current process of delamination requires multiple time-, energy-, and waste-intensive steps and still fails to delaminate some MXenes. Herein, we demonstrate a method of high-energy delamination called high-pressure homogenization (HPH) that combines high shear, cavitation forces, and impact forces to delaminate MXene without any post-process refinement steps or chemical intercalants. HPH-delaminated MXene can be made at scale with high throughput and yield with virtually no waste. We demonstrate the viability of this process by fabricating free-standing films with the material for use as electrodes for energy storage and as an effective antimicrobial coating where any residual lithium is undesirable. HPH-MXene electrodes demonstrated comparable capacitance to that of lithium-delaminated films with better rate capability. HPH-MXene films proved effective as antimicrobial coatings with over a two-log reduction in pathogenic microbes without the concern of chemical leaching by the coating. We anticipate that this method will decrease the cost of MXene manufacturing and be applicable to a variety MXenes, including those that cannot be currently delaminated via intercalation.

Shear stress-induced delamination method for the mass production of Ti3C2Tx MXene nanosheets

MXene nanosheets are considered advantageous for functional materials, but current delamination methods to prepare MXene nanosheets have many limitations including high cost, small production scale, low efficiency, and deteriorated structure integrity of obtained nanosheets. Here, we propose a simple, efficient, and scalable shear stress-induced delamination (SSID) strategy to boost the production of single-/few-layered Ti3C2Tx MXene nanosheets. Molecular dynamics simulation indicates that the pan mill-type grinding discs create a strong hydrodynamic flow field, which exerts gigantic shear stress to substantially delaminate the multilayered MXene stacks into homogeneously dispersed MXene nanosheets. Furthermore, shear stress generated from vigorous water flow has limited fragmentation effect, ensuring large lateral size and good structure integrity to the obtained MXene nanosheets as evidenced by the morphological and structural characterizations. Compared to conventional delamination methods, this novel SSID strategy exhibits great advantages in terms of efficiency, scalability and the properties of resultant MXene nanosheets, which opens up great opportunity for the scalable production and commercialization of high-performance MXene-based materials.

Can MXene be the Effective Nanomaterial Family for the Membrane and Adsorption Technologies to Reach a Sustainable Green World?

Environmental pollution has intensified and accelerated due to a steady increase in the number of industries, and exploring methods to remove hazardous contaminants, which can be typically divided into inorganic and organic compounds, have become inevitable. Therefore, the development of efficacious technology for the separation processes is of paramount importance to ensure the environmental remediation. Membrane and adsorption technologies garnered attention, especially with the use of novel and high performing nanomaterials, which provide a target-specific solution. Specifically, widespread use of MXene nanomaterials in membrane and adsorption technologies has emerged due to their intriguing characteristics, combined with outstanding separation performance. In this review, we demonstrated the intrinsic properties of the MXene family for several separation applications, namely, gas separation, solvent dehydration, dye removal, separation of oil-in-water emulsions, heavy metal ion removal, removal of radionuclides, desalination, and other prominent separation applications. We highlighted the recent advancements used to tune separation potential of the MXene family such as the manipulation of surface chemistry, delamination or intercalation methods, and fabrication of composite or nanocomposite materials. Moreover, we focused on the aspects of stability, fouling, regenerability, and swelling, which deserve special attention when the MXene family is implemented in membrane and adsorption-based separation applications.

Carbon Fiber Reinforced Plastics Based on an Epoxy Binder with the Effect of Thermally Induced Self-Repair

The authors have proposed the novel approach for evaluation of the self-healing effect in carbon fiber reinforced plastics (CFRP) on micro- and macro samples, using the dynamic mechanical analysis (DMA) and the double-cantilever beam delamination methods, respectively. A modified epoxy resin with a self-healing effect was used as the matrix for carbon plastics. The flexural modulus E’ of microsamples with delamination and the specific delamination energy (crack resistance) GIR of macrosamples with a given initial crack were chosen as criteria for evaluating the self-healing of carbon plastics. The sensitivity of the E’ and GIR parameters to the applied initial crack is shown. The value of the elastic modulus E’ with the initial crack can be reduced up to two times compared to the E’ values for the control materials, depending on the length of the initial crack. The degree of recovery of E’ for CFRP with a microcrack varies from 91 to 118%. A high degree of healing could be achieved in 48 h. The GIR value of CFRP samples with a given macroseparation after heat treatment is 7% of the initial GIR value (0.7 kJ/m2). Recovery of delaminations for microsamples is more efficient than for macrosamples. The study of CFRP cracks by X-ray tomography before and after self-healing showed that the crack “overgrows” during the heat treatment cycle, and the defects (pores) formed during the manufacture of the sample decrease in size.

Drilling study on CFRP/Al stack with different CFRP thickness using chip-breaking step drill bit

Low-defect and high-accurate drilling is required for CFRP/Al stack assembly, while unexpected drill defects and inconsistency of hole diameter are often found in drilling different thickness stacks due to the lack of proper drilling process. First, a novel quantifying method for CFRP delamination and Al burr is proposed and a new quality indicator for hole diameter is developed to ensure the accuracy of evaluating the drilling quality. The stacks with different thicknesses were compared, and the subsequent effects of machining parameters on drilling quality were comprehensively investigated. Then considering the thrust force and drilling temperature together, the influence of thermal-mechanical interaction on the hole defects was elucidated for the first time in drilling different thick stacks. The results show that the thicker stacks increased the drilling temperature for the prolonged tool/material engagement time, and that the stiffness and strength of drilled material were reduced progressively as the higher temperature, leading to the lower thrust force. For the CFRP delamination, the thickness of the stack is found to be another significant factor determining the delamination damage, and a better CFRP quality can be obtained in drilling thicker stacks. The height of Al burr increased with the thickness increased due to the main effects of the increased temperature, but which decreased and then increased with the feed because the decreased drilling temperature played at low feed while decreased thrust force at a high feed played a decisive role separately. Smaller diameter deviation was found in drilling thicker stacks, for the reduced thrust force leading to the decreased deformation. Besides, the diameter deviation decreased with feed increased as the reduced temperature played a main role at low feed, while diameter deviation increased at a high feed because the thrust force increased. Finally, a multiple-objective optimization was modelled, and optimum drilling conditions for achieving desired hole quality were determined with the chip-breaking step drill bit for drilling different CFRP/Al stacks.

Conceptual Design of a Semi-Automatic Process Line for Recycling Photovoltaic Panels as a Way to Ecological Sustainable Production

The article presents the developed technology for the comprehensive recycling of depleted, used or damaged photovoltaic (PV) cells made of crystalline silicon. The developed concepts of technology and the results of research on recycling were presented on silicon photovoltaic cells and modules. The sequence of steps and the type of procedures used are proposed. A thermal delamination method for used commercial photovoltaic modules has been developed to separate the materials. In addition, a recycling line was proposed along with the selection of machines and a holistic approach to project profitability based on a SWOT analysis. The presented semi-automatic installation enables recycling on a laboratory scale. The line was designed for the assumed capacity of 30 t/h. The total energy demand for the designed line was calculated, which showed that 16.49 kWh is needed to recycle 1 ton of photovoltaic laminates. Implementation of developed solutions on an industrial scale will allow to reduce production costs, mainly thanks to energy savings, which translates into less devastation of the natural environment and reduced material consumption. In addition, the implementation of the PV module recycling system will reduce and, consequently, eliminate a significant amount of used PV devices deposited in landfills. The content of the article gives a fresh and innovative look at the essence of photovoltaic panel recycling processes in terms of production benefits as well as financial and environmental benefits.

Hydrofluoric Acid-Free Synthesis of Ti3C2Tx MXene Nanostructures for Energy Applications

The preparation of titanium carbide (Ti3C2Tx) thin sheets (T represents surface termination), an emerging class of two-dimensional materials, heavily relies on the etching of interlayered aluminum (Al) of MAX (M, A, and X represent transition metals, Al, and carbon, respectively) using concentrated hydrofluoric acid (HF). However, HF is an acutely toxic chemical. Herein, for the first time, we propose a dissolution-driven delamination method to prepare Ti3C2Tx MXene thin sheets using an HF-free solvent to remove the interlayers of Al. Bis(trifluoromethanesulfonyl)imide (TFSI) is a delaminating agent that can directly and effectively dissolve the Al interlayers of MAX. The role of TFSI in this delamination process, i.e., the preferential formation of the surface of a Ti3C2Tx thin sheet, is a key parameter for superior supercapacitor application. The prepared Ti3C2Tx sheets were loaded on Ni foam (NF) via a hydrothermal reaction to form a Ti3C2Tx MXene/NF-4 h composite electrode. This Ti3C2Tx MXene/NF-4 h composite electrode exhibits the highest unprecedented capacitance of 3090 F/g at a current density of 10 A/g in a 1 M KOH electrolyte. It also exhibits excellent rate capabilities at different current densities (from 10 to 30 A/g) while maintaining 76.4% capacity retention after long life cycles. This study provides fundamental insights into the effect of the dissolution of interlayered Al of Ti3AlC2 on the preparation of Ti3C2Tx thin sheets as well as sheds light on the development of next-generation flexible and simple integrated supercapacitors with excellent gravimetric performance.