Silicon oxycarbides can be considered as being carbon‐containing silicates consisting of glass networks in which oxygen and carbon share bonds with silicon. The carbon‐for‐oxygen substitution in ...silicate glass networks has been shown to induce significant changes in the network connectivity and consequently strong improvements in the properties of the silicate glass network. For instance, SiOC glasses exhibit Young's moduli, hardness values, glass transition, and crystallization temperatures which are superior to those of vitreous silica. Moreover, the silicon oxycarbide glass network exhibits unique structural features such as reduced mass fractal dimension and nano‐heterogeneity, which significantly affect and/or dictate its properties and behavior. In the present Review, a consideration of the current state of the art concerning the synthesis, processing, and various structural and functional properties of silicon‐oxycarbide‐based glasses and glass‐ceramics is done. Thus, the synthesis of silicon oxycarbides starting from macromolecular precursors such as polysiloxanes or alkoxysilanes‐based sol‐gel systems as well as current advances related to their processing will be critically reviewed. In addition, various structural and functional properties of silicon oxycarbides are presented. Specific emphasis will be put on the intimate correlation between the molecular architecture of the precursors and the structural features and properties of the resulting silicon oxycarbides.
In the present Review, a consideration of the current state of the art concerning the synthesis, processing as well as various structural and functional properties of silicon‐oxycarbide‐based materials is done.
The proliferation of rechargeable lithium‐ion batteries (LIBs) over the past decade has led to a significant increase in the number of electric vehicles (EVs) powered by these batteries reaching the ...end of their lifespan. With retired EVs becoming more prevalent, recycling and reusing their components, particularly graphite, has become imperative as the world transitions toward electric mobility. Graphite constitutes ≈20% of LIBs by weight, making it a valuable resource to be conserved. This review presents an in‐depth analysis of the current global graphite mining landscape and explores potential opportunities for the “second life” of graphitefrom depleted LIBs. Various recycling and reactivation technologies in both industry and academia are discussed, along with potential applications for recycled graphite forming a vital aspect of the waste management hierarchy. Furthermore, this review addresses the future challenges faced by the recycling industry in dealing with expired LIBs, encompassing environmental, economic, legal, and regulatory considerations. In conclusion, this review provides a comprehensive overview of the developments in recycling and reusing graphite from retired LIBs, offering valuable insights for forthcoming large‐scale recycling efforts.
Expired lithium‐ion batteries (LIBs) contain valuable battery‐grade graphite materials. However, graphite is largely overlooked due to its lower profitability compared to cathode materials. This review discusses the future challenges facing the recycling industry in handling waste graphite and provides a comprehensive overview of the development of graphite recycling and reuse from spent LIBs, offering valuable insights for upcoming large‐scale recycling efforts.
Since the 1960s, a new class of Si-based advanced ceramics called polymer-derived ceramics (PDCs) has been widely reported because of their unique capabilities to produce various ceramic materials ...(e.g., ceramic fibers, ceramic matrix composites, foams, films, and coatings) and their versatile applications. Particularly, due to their promising structural and functional properties for energy conversion and storage, the applications of PDCs in these fields have attracted much attention in recent years. This review highlights the recent progress in the PDC field with the focus on energy conversion and storage applications. Firstly, a brief introduction of the Si-based polymer-derived ceramics in terms of synthesis, processing, and microstructure characterization is provided, followed by a summary of PDCs used in energy conversion systems (mainly in gas turbine engines), including fundamentals and material issues, ceramic matrix composites, ceramic fibers, thermal and environmental barrier coatings, as well as high-temperature sensors. Subsequently, applications of PDCs in the field of energy storage are reviewed with a strong focus on anode materials for lithium and sodium ion batteries. The possible applications of the PDCs in Li-S batteries, supercapacitors, and fuel cells are discussed as well. Finally, a summary of the reported applications and perspectives for future research with PDCs are presented.
Silicon oxycarbide/tin nanocomposites (SiOC/Sn) are prepared by chemical modification of polysilsesquioxane Wacker‐Belsil PMS MK (SiOCMK) and polysiloxane Polyramic RD‐684a (SiOCRD) with ...tin(II)acetate and subsequent pyrolysis at 1000 °C. The obtained samples consist of an amorphous SiOC matrix and in‐situ formed metallic Sn precipitates. Galvanostatic cycling of both composites demonstrate a first cycle reversible capacity of 566 mAhg−1 for SiOCMK/Sn and 651 mAhg−1 for SiOCRD/Sn. The superior cycling stability and rate capability of SiOCRD/Sn as compared to SiOCMK/Sn is attributed to the soft, carbon‐rich SiOC matrix derived from the RD‐684a polymer, which accommodates the Sn‐related volume changes during Li‐uptake and release. The poor cycling stability found for SiOCMK/Sn relates to mechanical failure of the rather stiff and fragile, carbon‐poor matrix produced from PMS MK. Incremental capacity measurements outline different final Li–Sn alloy stages, depending on the matrix. For SiOCRD/Sn, alloying up to Li7Sn2 is registered, whereas for SiOCMK/Sn Li22Sn5 stoichiometry is reached. The suppression of Li22Sn5 phase in SiOCRD/Sn is rationalized by an expansion restriction of the matrix and thus prevention of a higher Li content in the alloy. For SiOCMK/Sn on the contrary, the matrix severely ruptures, providing an unlimited free volume for expansion and thus formation of Li22Sn5 phase.
Enhanced lithium storage stability of single‐source precursor‐derived SiOC/Sn nanocomposites is demonstrated. The nanocomposites comprise an amorphous SiOC matrix and in‐situ formed Sn precipitates. Capacity measurements outline different final Li–Sn alloy stages, depending on the matrix. Galvanostatic cycling shows a first cycle reversible capacity of 566 mAhg−1 for SiOCMK/Sn and 651 mAhg−1 for SiOCRD/Sn.
In this work, we present the electrochemical behavior and microstructural analysis of silicon oxycarbide (SiOC) ceramics influenced by an addition of polystyrene (PS). Polymer‐derived ceramics were ...obtained by pyrolysis (1000°C, Ar atmosphere) of different polysiloxanes prepared by sol–gel synthesis. This method is very effective to obtain desired composition of final ceramic. Two alkoxysilanes phenylthriethoxysilane and diphenyldimethoxysilane were used as precursors. Before pyrolysis polysiloxanes were mixed with PS using toluene as a solvent. Blending with PS affects the microstructure and free carbon content in the final ceramic material. Free carbon phase has been confirmed to be a major lithium storage host. Nevertheless, we demonstrate here that capacity does not increase linearly with increasing carbon content. We show that the amount of SiO4 units in the SiOC microstructure increases the initial capacity but decreases the cycling stability and rate capability of the material. Furthermore, the microstructure of the free carbon influences the electrochemical performance of the ceramic: More ordered graphitic clusters favor better rate capability performance.
A detailed analysis of morphology of gallium nitride crystal growth obtained by ammonothermal and halide vapor phase epitaxy methods was carried out. The work was conducted to determine the source of ...triangular planar defects visible in X-ray topography as areas with locally different lattice parameters. It is shown that the occurrence of these defects is related to growth hillocks. Particular attention was paid to analyzing the manner and consequences of merging hillocks. In the course of the study, the nature of the mentioned defects and the cause of their formation were determined. It was established that the appearance of the defects depends on the angle formed between the steps located on the sides of two adjacent hillocks. A universal growth model is presented to explain the cause of heterogeneity during the merging of growth hillocks.
SiOC ceramic aerogels with different porosity, pore size, and specific surface area have been synthesized through the polymer‐derived ceramic route by modifying the synthesis parameters and the ...pyrolysis steps. Preceramic aerogels are prepared by cross‐linking a linear polysiloxane with divinylbenzene (DVB) via hydrosilylation reaction in the presence of a Pt catalyst under highly diluted conditions. Acetone and cyclohexane are used as solvent in our study. Wet gels are subsequently supercritically dried with CO2 to get the final preceramic aerogels. The SiOC ceramic aerogels are obtained after a pyrolysis treatment at 900°C in two different atmospheres: pure Ar and H2 (3%)/Ar mixtures. The nature of the solvent has a profound influence of the aerogel microstructure in terms of porosity, pore size, and specific surface area. Synthesized SiOC ceramic aerogels have similar chemical compositions irrespective of processing conditions with ~40 wt% of free carbon distributed within remaining mixed SiOC matrix. The BET surface areas range from 215 m2/g for acetone samples to 80 m2/g for samples derived from cyclohexane solvent. The electrochemical characterization reveals a high specific reversible capacity of more than 900 mAh/g at a charging rate of C (360 mA/g) along with a good cycling stability. Samples pyrolyzed in H2/Ar atmosphere show a high reversible capacity of 200 mAh/g even at a high charging/discharging rate of 20 C. Initial capacities were recovered after whole cycling procedure indicating their structural stabilities resisting any kind of exfoliations.
•Cephalosporin resistance in commensal Escherichia coli was characterized.•blaCTX-M-1/-61, blaSHV-12blaTEM-1,-52/-92,-135, and blaCMY-2 prevailed.•blaSHV-12 and blaCTX-M-1/-61 genes were located on ...transmissible X1 plasmids.•Resistance genes reservoir in farm animals is confirmed.•Ecological aspects of selection and dissemination of cephalosporin resistance is underlined.
Resistance to β-lactams is considered one of the major global problems and recently it became the most frequently studied topic in the area of antimicrobial resistance. The study was focused on phenotypic and genetic characterisation of commensal Escherichia coli (E. coli), including those producing cephalosporinases, isolated from gut flora of healthy slaughter animals. E. coli were cultured simultaneously on MacConkey agar (MCA) and cefotaxime supplemented MCA. The isolates were confirmed with ONPG and indol tube tests as well as PCR targeting uspA gene. Microbroth dilution method was applied for determination of Minimal Inhibitory Concentrations and interpreted according to EUCAST epidemiological cut-off values. Cephalosporin resistance phenotypes were defined by E-tests (BioMerieux) and relevant gene amplicons from selected strains were sequenced. A total of 298 E. coli isolates with cephalosporin resistance (ESC) found in 99 ones, were obtained from 318 cloacal or rectal swabs deriving from broilers, layers, turkeys, pigs and cattle. Both extended spectrum β-lactamase (ESBL) and ampC-cephalosporinase resistance phenotypes were noted in all tested animal species but cattle. At least one of the analysed genes was identified in 90 out of 99 cephalosporin-resistant isolates: blaTEM (n=44), blaCMY (n=38), blaCTX-M (n=33) and blaSHV (n=12). None of the phenotypes was identified in nine isolates. Sequencing of PCR products showed occurrence of ESBL-genes: blaCTX-M-1/-61, blaSHV-12, blaTEM-1,-52/-92,-135 and ampC-gene blaCMY-2. They were located on numerous and diverse plasmids and resistance transferability was proved by electroporation of blaSHV-12 and blaCTX-M-1/-61 located on X1 plasmids. Detection of cephalosporin resistant E. coli confirms the existence of resistance genes reservoir in farm animals and their possible spread (i.e. via IncX1 plasmids) to other bacteria including human and animal pathogens. The identified genetic background indicates on ecological aspects of selection and dissemination of cephalosporin resistance in E. coli isolated from food-producing animals rather than its potential role for public health threats.
Sodium‐ion batteries (SIBs) are a cost‐effective and sustainable alternative to lithium‐ion batteries (LIBs), which might be independent of rare raw materials. These advantages come at the expense of ...low energy density. Sodium metal batteries (SMBs) can provide a possible solution. In this work, we present the use of a porous silicon carbonitride (SiCN(O)) ceramic as an anodic matrix for reversible Na‐plating. The role of the pores is investigated and the plating mechanism allowing reversible and uniform plating/stripping of sodium is also presented. Electrochemical studies show a stable and reversible capacity gain of around 60 mAh/g beyond the insertion capacity of the SiCN(O) ceramic over 100 cycles.
Highly porous anodic matrix for Na‐plating/stripping: The porosity of SiCN(O) makes this ceramic attractive as a matrix for reversible plating of metallic sodium on the anodic side. The pores serve as an energetically favourable nucleation site reducing the risk of uncontrolled dendrite growth allowing to take advantage of the high gravimetric capacity (1166 mAh/g) of metallic sodium.
Reptiles are considered a reservoir of a variety of Salmonella (S.) serovars. Nevertheless, due to a lack of large-scale research, the importance of Reptilia as a Salmonella vector still remains not ...completely recognized. A total of 731 samples collected from reptiles and their environment were tested. The aim of the study was to assess the prevalence of Salmonella in exotic reptiles kept in Poland and to confirm Salmonella contamination of the environment after reptile exhibitions. The study included Salmonella isolation and identification, followed by epidemiological analysis of the antimicrobial resistance of the isolates. Implementation of a pathway additional to the standard Salmonella isolation protocol led to a 21% increase in the Salmonella serovars detection rate. The study showed a high occurrence of Salmonella, being the highest at 92.2% in snakes, followed by lizards (83.7%) and turtles (60.0%). The pathogen was also found in 81.2% of swabs taken from table and floor surfaces after reptile exhibitions and in two out of three egg samples. A total of 918 Salmonella strains belonging to 207 serovars and serological variants were obtained. We have noted the serovars considered important with respect to public health, i.e., S. Enteritidis, S. Typhimurium, and S. Kentucky. The study proves that exotic reptiles in Poland are a relevant reservoir of Salmonella.
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