Nanocomposites with enhanced mechanical properties and efficient self‐healing characteristics can change how the artificially engineered materials’ life cycle is perceived. Improved adhesion of ...nanomaterials with the host matrix can drastically improve the structural properties and confer the material with repeatable bonding/debonding capabilities. In this work, exfoliated 2H‐WS2 nanosheets are modified using an organic thiol to impart hydrogen bonding sites on the otherwise inert nanosheets by surface functionalization. These modified nanosheets are incorporated within the PVA hydrogel matrix and analyzed for their contribution to the composite's intrinsic self‐healing and mechanical strength. The resulting hydrogel forms a highly flexible macrostructure with an impressive enhancement in mechanical properties and a very high autonomous healing efficiency of 89.92%. Interesting changes in the surface properties after functionalization show that such modification is highly suitable for water‐based polymeric systems. Probing into the healing mechanism using advanced spectroscopic techniques reveals the formation of a stable cyclic structure on the surface of nanosheets, mainly responsible for the improved healing response. This work opens an avenue toward the development of self‐healing nanocomposites where chemically inert nanoparticles participate in the healing network rather than just mechanically reinforcing the matrix by slender adhesion.
On the supposedly hard‐to‐modify 2D transition metal dichalcogenides, a technique for adding chemical functional groups is introduced. In addition to significantly strengthening polymer‐based nanocomposites, the resulting material also encourages autonomous self‐healing when damaged. The composite attained a 90% healing efficiency by creating a stable cyclic structure on the surface of nanosheets.
The rapid growth of electric vehicle use is expected to cause a significant environmental problem in the next few years due to the large number of spent lithium‐ion batteries (LIBs). Recycling spent ...LIBs will not only alleviate the environmental problems but also address the challenge of limited natural resources shortages. While several hydro‐ and pyrometallurgical processes are developed for recycling different components of spent batteries, direct regeneration presents clear environmental, and economic advantages. The principle of the direct regeneration approach is restoring the electrochemical performance by healing the defective structure of the spent materials. Thus, the development of direct regeneration technology largely depends on the formation mechanism of defects in spent LIBs. This review systematically details the degradation mechanisms and types of defects found in diverse cathode materials, graphite anodes, and current collectors during the battery's lifecycle. Building on this understanding, principles and methodologies for directly rejuvenating materials within spent LIBs are outlined. Also the main challenges and solutions for the large‐scale direct regeneration of spent LIBs are proposed. Furthermore, this review aims to pave the way for the direct regeneration of materials in discarded lithium‐ion batteries by offering a theoretical foundation and practical guidance.
The direct regeneration of spent lithium‐ion batteries (LIBs) has attracted considerable attention compared to traditional recycling methods. Only by having an adequate understanding of degradation mechanisms and defective types of failed materials can be found more suitable and efficient methods for direct repairing spent LIBs. A comprehensive overview of degradation mechanisms and regeneration methods for spent LIBs is provided.
Printed graphene supercapacitors have the potential to empower tomorrow's wearable electronics. We report a solid-state flexible supercapacitor device printed on textiles using graphene oxide ink and ...a screen-printing technique. After printing, graphene oxide was reduced in situ via a rapid electrochemical method avoiding the use of any reducing reagents that may damage the textile substrates. The printed electrodes exhibited excellent mechanical stability due to the strong interaction between the ink and textile substrate. The unique hierarchical porous structure of the electrodes facilitated ionic diffusion and maximised the surface area available for the electrolyte/active material interface. The obtained device showed outstanding cyclic stability over 10 000 cycles and maintained excellent mechanical flexibility, which is necessary for wearable applications. The simple printing technique is readily scalable and avoids the problems associated with fabricating supercapacitor devices made of conductive yarn, as previously reported in the literature.
One-dimensional nanotubes constructed from interconnected Li1.2Mn0.54Ni0.13Co0.13O2 secondary particles of diameters measuring ca. 40 nm, were synthesized by a one-pot electrospinning method. Novel ...electrodes were constructed from (a) nanoparticles only, and (b) hollow nanofibres, and employed as cathodes in Li-ion batteries. The nanotube cathode exhibited impressive specific charge capacity, good cycling stability, and excellent rate capability. A discharge capacity of 140 mAh g−1 with capacity retention of 89% at 3 C was achieved after 300 cycles. The significant improvement of electrochemical performance is attributed to the high surface area of the nanotubes, well-guided charge transfer kinetics with short ionic diffusion pathways, and large effective contact area with the electrolyte during the cycling process.
•Nanotubes of Li1.2Mn0.54Ni0.13Co0.13O2 is proposed as an Li-ions batteries cathode.•An affordable one-pot electrospinning method is introduced to fabricate the nanotubes.•The improved cyclic stability and rate capability are demonstrated.
Multiwalled carbon nanotube (MWNT)/cellulose composite nanofibers have been prepared by electrospinning a MWNT/cellulose acetate blend solution followed by deacetylation. These composite nanofibers ...were then used as precursors for carbon nanofibers (CNFs). The effect of nanotubes on the stabilization of the precursor and microstructure of the resultant CNFs were investigated using thermogravimetric analysis, transmission electron microscopy and Raman spectroscopy. It is demonstrated that the incorporated MWNTs reduce the activation energy of the oxidative stabilization of cellulose nanofibers from ∼230 to ∼180 kJ mol–1. They also increase the crystallite size, structural order, and electrical conductivity of the activated CNFs (ACNFs). The surface area of the ACNFs increased upon addition of nanotubes which protrude from the fiber leading to a rougher surface. The ACNFs were used as the electrodes of a supercapacitor. The electrochemical capacitance of the ACNF derived from pure cellulose nanofibers is demonstrated to be 105 F g–1 at a current density of 10 A g–1, which increases to 145 F g–1 upon the addition of 6% of MWNTs.
The effect of the lateral dimensions of the graphene reinforcement on the physical properties of poly(methyl methacrylate) (PMMA) nanocomposites was studied. Electrochemically-exfoliated, few-layer ...graphene with average diameters of 5μm (5-FLG) and 20μm (20-FLG) were incorporated into a PMMA matrix at loadings from 0.5 to 20wt.% by melt mixing using a twin screw compounder. The smaller graphene flakes were found to have only a slight effect on the rheological properties of the PMMA, whereas the larger flakes significantly increased the viscosity and dynamic moduli of the PMMA melt. Mechanical testing showed that the 5μm flakes behaved in a similar way to short fibers and reinforced the PMMA matrix poorly compared to the 20μm flakes, in line with previous predictions on the critical length of graphene. Significantly, these larger flakes gave a linear increase in the modulus with loading even at high loadings, without any of the detrimental aggregation effects seen in most other graphene systems.
In the last two decades, tremendous work has been investigating the electro-reduction of metal oxide cathodes in what is known as the FFC-Cambridge process. This paper explores the electrolyte ...changes that occur during the electro-deoxidation of metal oxides. The investigation takes niobium oxide as a case study and subjects a Nb2O5 cathode to a constant potential difference of 2.5V between the cathode and carbon anode during the in-situ recording of the cyclic voltammetry of the electrolyte on a glassy carbon electrode. The deoxidation of the cathode supplies oxygen ions that increase the oxygen content of the electrolyte, even in the very early stage of the process. We could detect many non-Faradic processes and increase the electrolyte electronic and ionic conductivity a few hours after starting the electro-deoxidation due to the reduction of CaO. It was also possible to detect partial dissolution of the cathode in the electrolyte and back deposition of Nb on the current collector. The dissolved niobium ions can combine with the oxide ion in the melt to form a negatively charged complex which can be discharged on the anode to form a thick ceramic layer. The electrolyte changes were also investigated using electrochemical impedance spectroscopy.
Nanocrystalline powder of hafnium-rich-HfC has been successfully synthesised by the electro-deoxidation of HfO2–carbon precursors in molten chloride. The progress of the solid state reduction was ...monitored ex situ by analysing partially reduced samples using X-ray diffraction (XRD) and scanning electron microscopy (SEM). It has been shown that the reduction started by converting HfO2 to CaHfO3 and an oxycarbide phase of the form HfCxO2(1−x). The CaHfO3 phase then also reduced to give HfCxO2(1−x), which subsequently reduced to HfC by ionising oxygen. The morphological analysis indicated almost no growth in the grain size occurred during the course of the electro-deoxidation. This investigation showed some loss of carbon during the electro-deoxidation resulted in metallic rich HfC. The synthesised powder exhibited better sinterability than the commercial HfC powder. Using the synthesised powder, fully dense monolithic HfC ceramics were produced by pressureless sintering at 1973K with average grain size of about 3μm.
Background
Many drugs have been restricted in the treatment of gastric ulcers (GU). So, herbal medicines are now in great demand for their better cultural acceptability, compatibility, and minimal ...side effects. Therefore, our study aimed to assess the protective efficacy of
Aloe vera
gel and
Geranium robertianum
extracts against Aspirin®-induced GU in Wistar rats.
Methods
Antioxidant activity and chemical composition of both herbs were analysed. Then, we divided forty female Wistar rats into five groups: a negative control group, a positive control group of Aspirin®-induced GU, and pretreated groups with
Aloe Vera
, geranium, and Famotidine (reference drug). The locomotor disability, anxiety-like behaviour, and ultrasonography were assessed. Ultimately, scarification of animals to determine gastric juice pH and ulcer index. Then the collection of stomach and liver for histopathological and immunohistochemical examinations, besides tracing the oxidative stress biomarkers and related genes.
Results
High content of polyphenols was revealed in both extracts. The pretreatment with
Aloe vera
gel and geranium showed significant antioxidant activities with free radical scavenging and ferric-reducing power (FRAP). Moreover, they improved the stomach architecture and alleviated anxiety-like behaviour and motor deficits. They significantly reduced the expression of proinflammatory cytokine (TNF-α), inflammatory, and oxidative stress genes (NF-KB, HO-1, Nrf-2) while increasing the Keap-1 in gastric mucosa.
Conclusion
Data presented a significant protective effect of
Aloe vera
gel and geranium against Aspirin®-induced GU; they reduced gastric mucosal injury with potential anxiolytic effects through their anti-inflammatory and antioxidant properties. Therefore, they may be considered promising agents for preventing or treating gastric ulceration.
Aflatoxin B1 (AFB1) is a common environmental pollutant that poses a major hazard to both humans and animals. Acacia senegal (Gum) is well-known for having antioxidant and anti-inflammatory bioactive ...compounds. Our study aimed to scout the nephroprotective effects of Acacia gum (Gum) against AFB1-induced renal damage. Four groups of rats were designed: Control, Gum (7.5 mg/kg), AFB1 (200 µg/kg b.w) and AFB1-Gum, rats were co-treated with both Gum and AFB1. Gas chromatography-mass spectrometry (GC/MS) analysis was done to determine the phytochemical constituents in Gum. AFB1 triggered profound alterations in kidney function parameters (urea, creatinine, uric acid, and alkaline phosphatase) and renal histological architecture. Additionally, AFB1 exposure evoked up-regulation of mRNA expression levels of inflammatory cytokines, including interleukin-6 (IL-6), tumor necrosis factor α (TNFα), inducible nitric oxide synthase (iNOS), and nuclear factor kB p65 (NF-κB/P65) in renal tissue. The oxidative distress and apoptotic cascade are also instigated by AFB1 intoxication as depicted in down-regulated protein expression of the nuclear factor erythroid 2–related factor 2 (Nrf2) and superoxide dismutase type 1 (SOD1) along with upregulation of cytochrome c (Cyto c), and cleaved Caspase3 (Casp3–17 and 19) in renal tissue. In conclusion, current study obviously confirms the alleviating effects of Gum supplementation against AFB1-induced renal dysfunction, oxidative harm, inflammation, and cell death. These mitigating effects are suggested to be attributed to Gum's antioxidant and anti-inflammatory activities. Our results recommend Gum supplementation as add-on agents to food that might aid in protection from AFB1-induced nephrotoxicity.
•Aflatoxin B1- provoked renal damage via oxidative stress and inflammatory pathways.•Acacia senegal (Gum) ameliorates AFB1-induced renal damage.•Gum inhibits oxidative stress and inflammation in the AFB1-induced renal damage.•Gum reduces AFB1-induced apoptosis in rats’ kidney.•Gum supplementation has therapeutic potential against AFB1-induced renal damage.
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