Search Results (223)

This research focuses on designing polymer membranes as biocompatible materials using home-built electrospinning equipment, offering alternative solutions for tissue regeneration applications. This technological development supports cell growth on biomaterial substrates, including hepatocellular carcinoma (Hep-G2) cells. This work researches the compatibility of polymer membranes (fiber mats) made of polyvinylidene difluoride (PVDF) for possible use in cellular engineering. A standard culture medium was employed to support the proliferation of Hep-G2 cells under controlled conditions (37 °C, 4.8% CO₂, and 100% relative humidity). Subsequently, after the incubation period, electrochemical impedance spectroscopy (EIS) assays were conducted in a physiological environment to characterize the electrical cellular response, providing insights into the biocompatibility of the material. Scanning electron microscopy (SEM) was employed to evaluate cell adhesion, morphology, and growth on the PVDF polymer membranes. The results suggest that PVDF polymer membranes can be successfully produced through electrospinning technology, resulting in the formation of a dipole structure, including the possible presence of a polar β-phase, contributing to piezoelectric activity. EIS measurements, based on R_ct and C_dl values, are indicators of ion charge transfer and strong electrical interactions at the membrane interface. These findings suggest a favorable environment for cell proliferation, thereby enhancing cellular interactions at the fiber interface within the electrolyte. SEM observations displayed a consistent distribution of fibers with a distinctive spherical agglomeration on the entire PVDF surface. Finally, integrating piezoelectric properties into cell culture systems provides new opportunities for investigating the influence of electrical interactions on cellular behavior through electrochemical techniques. Based on the experimental results, this electrospun polymer demonstrates great potential as a promising candidate for next-generation biomaterials, with a probable application in tissue regeneration. Full article

Understanding the relationships between design factors is crucial for the development of hydrogel supercapacitors, yet the relative importance and interdependencies of material properties and operating conditions remain unclear. This study employs interpretable machine learning to analyze the design factors that affect hydrogel supercapacitor performance, using 232 experimental samples from 41 recent studies. SHAP analysis was implemented to quantify parameter importance and reveal feature interactions among 16 key design parameters, including polymer types, electrolyte formulations, and operating conditions. Results show that synthetic vinyl polymers most strongly influence specific capacitance, while conductive polymers predominantly affect cycle stability. Ionic conductivity emerged as the most impactful parameter despite moderate feature importance, indicating complex nonlinear relationships. Critical interdependencies between polymer concentration and electrolyte formulation suggest that optimal design requires coordinated parameter selection rather than independent optimization. This interpretable framework provides quantitative insights into design factor hierarchies and parameter interdependencies, offering evidence-based guidelines for rational material selection in hydrogel supercapacitor development. Full article

This work mainly explores whether the solubility product principle has a guiding role in regulating the composition of micro-arc oxidation (MAO) coatings. The MAO process was conducted on AZ31 Mg alloy in silicate electrolyte. Varying amounts of Potassium fluoride (KF) and Ammonium fluoride (NH₄F) were separately added to the basic electrolyte to regulate the OH⁻ and F⁻ contents in the electrolyte. The microstructure, phase composition and corrosion resistance of the MAO coatings prepared in different electrolytes were analyzed. Results showed that regardless of KF content, MgO was the main component for the MAO coatings obtained in electrolytes with KF. This was because the addition of KF not only elevated the F⁻ concentration in the electrolyte but also enhanced the OH⁻ concentration as a result of F⁻ hydrolysis. Based on the solubility product constants (Ksp) of MgO and MgF₂, a relatively lower concentration of Mg²⁺ was sufficient for the formation of MgO. Hence, Mg²⁺ consistently exhibited preferential reactivity with OH⁻, leading to the formation of MgO. The findings of the study demonstrated that the presence of KF electrolyte resulted in an enhancement of conductivity and an increase in the concentration of OH⁻. Conversely, the growth rate of the coating was observed to be low, and the coating-forming phases of the coating were identified as MgO and Mg₂SiO₄, and the coating had better corrosion resistance. NH₄F electrolyte with the increase in NH₄F concentration, conductivity decreases and then increases, OH⁻ concentration decreases, the growth rate of the coating is faster, the concentration of F⁻/OH⁻ is higher, the coating-forming phase is transformed into MgF₂, and the corrosion resistance of the coating is reduced. Full article

Gel electrolytes (GEs) play a pivotal role in the advancement of lithium metal batteries by offering high energy density and enhanced rate capability. Nevertheless, their real-world application is hampered by relatively low ionic conductivity and significant interfacial resistance at room temperatures. In this work, we developed a gel electrolyte membrane (GEM) by embedding Zeolitic Imidazolate Framework-8 (ZIF-8) metal–organic frameworks (MOFs) material into a poly(vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP) matrix through UV curing. The composite membrane, with 4 wt% ZIF-8, exhibited an ionic conductivity of 1.17 × 10⁻³ S/cm, an electrochemical stability window of 4.7 V, and a lithium-ion transference number of 0.7. The test results indicate that the electrochemical performance of LFP//GEM//Li battery has an initial specific capacity of 168 mAh g⁻¹ at 0.1 C rate. At 1 C, the discharge capacity was 88 mAh g⁻¹, and at 2 C, it was 68 mAh g⁻¹. Enhanced ionic transport, improved electrochemical stability, and optimized lithium-ion migration collectively contributed to superior rate performance and prolonged cycle life. This study offers novel insights and methodological advances for next-generation lithium metal batteries technologies. Full article

This paper presents the results of an investigation into the effect of the physicochemical properties of carbon chars (biochars) on the performance of direct carbon solid oxide fuel cells (DC-SOFCs). Biochars were obtained from walnut, coconut, pistachio, hazelnut and peanut shells by pyrolysis at a temperature of 850 °C. The results of structural studies conducted using X-ray diffraction and Raman spectroscopy reflected a low degree of graphitisation of carbon particles. Biochar derived from walnut shells is characterised by a relatively uniform content of alkali elements, such as sodium, potassium, calcium, magnesium and iron, which are natural components of the mineral residue and act as catalysts for the Boudouard reaction. This study of gasification of biochar samples in a CO₂ atmosphere recorded that the highest conversion rate from solid phase to gaseous phase was for the biochar sample produced from walnut shells. The superior properties of this sample are directly connected to structural features, as well as to the random distribution of alkali elements. DC-SOFCs involving 10 mol% of Sc₂O₃, 1 mol% of CeO₂, 89 mol% of ZrO₂ (10S1CeZ) or 8 mol% of Y₂O₃ in ZrO₂ (8YSZ) were used as both solid oxide electrolytes and components of the anode electrode. It was found that the highest electrochemical power output (P_max) was achieved for DC-SOFCs fuelled by biochar from walnut shells, with around 103 mW/cm² obtained for such DC-SOFCs involving 10S1CeZ electrolytes. Full article

Solid-state electrolytes (SSEs) have emerged as the most promising alternative to liquid electrolytes in batteries due to their enhanced stability and safety. Among these, the garnet-type Li₇La₃Zr₂O₁₂ (LLZO) solid electrolyte has attracted significant research interest due to its wide electrochemical stability window and good air stability. However, the ionic conductivity of LLZO is lower due to its high sintering temperature and unstable phase structure. In this study, Li_6.4+xFe_0.2La₃Zr_2−xBi_xO₁₂ (x = 0, 0.05, 0.1, 0.15) solid electrolytes were synthesized using a conventional solid-state reaction method by co-doping LLZO with Fe³⁺ and Bi³⁺ ions. Compared with pure LLZO, doping with Fe³⁺ effectively stabilizes the cubic phase, thereby enhancing the ionic conductivity. Moreover, Bi³⁺ doping significantly lowers the sintering temperature of the electrolyte, which in turn reduces energy consumption during the processing. The co-doping of Fe³⁺ and Bi³⁺ not only improves the density of the LLZO electrolyte, achieving a relative density of up to 95%, but also increases the ionic conductivity, with a maximum value of 7.57 × 10⁻⁴ S·cm⁻¹ observed at the optimal composition (Li_6.4+xFe_0.2La₃Zr_2-xBi_xO₁₂, x = 0.1). Full article

In this work, we present a study on the thermal/transport properties of a novel deep eutectic solvent (DES) obtained by using N-methyltrifluoroacetamide (FNMA) as the hydrogen bond donor (HBD) and lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) as the hydrogen bond acceptor (HBA). The binary phase diagram, thermal stability, flammability, viscosity and ionic conductivity of the as-prepared DESs were investigated at atmospheric pressure. The binary phase diagram shows a range of eutectic molar ratios (x_LiTFSI = 0.2~0.33), with the lowest deep eutectic temperature of −84 °C. At x_LiTFSI = 0.2 (i.e., FNMA:LiTFSI = 4:1 and denoted as DES-4:1). The as-prepared DES composition exhibits high thermal stability (onset temperature of weight loss = 78 °C), a low viscosity (η = 48.9 mPa s at 25 °C), relatively high ionic conductivity (σ = 0.86 mS cm⁻¹ at 25 °C) and non-flammability. The transport properties, including ionic conductivity and viscosity, as a function of temperature are in accordance with the Vogel–Fulcher–Tammann (VFT) equations. With increasing molar ratio of HBD vs. HBA, the viscosity decreases, and the ionic conductivity increases at a given temperature between 25 °C and 80 °C. The roughly equal pseudo-activation energies for ion transport and viscous flow in each composition imply a strong coupling of ion transport and viscous flow. Walden plots indicate vehicular transport as the main ion transport mechanism for the DES-4:1 and DES-3:1 compositions; meanwhile, it was confirmed that the ionic conductivity and viscous flow are strictly coupled. The present work is expected to provide strategies for the development of wide-temperature-range and safer electrolytes with low salt concentrations. Full article

Background and Objectives: Chronic obstructive pulmonary disease (COPD) and acute respiratory failure are critical clinical conditions associated with high mortality rates in intensive care units (ICUs). Electrolyte imbalances are significant variables that may influence all-cause ICU mortality in this patient group. In this retrospective study, we aimed to investigate the relationships between the serum levels of sodium (Na⁺), chloride (Cl⁻), potassium (K⁺), calcium (Ca²⁺), and magnesium (Mg²⁺) and all-cause ICU mortality in patients admitted with respiratory failure. Additionally, we conducted a detailed mortality analysis on the basis of sodium quartiles and pathological absolute sodium thresholds to reveal their associations with ICU mortality from all causes. Materials and Methods: A total of 1109 patients were analyzed between January 2022 and January 2024. The electrolyte levels measured at ICU admission, demographic data, APACHE II and SOFA scores, arterial blood gas results, BUN and creatinine levels, need for noninvasive mechanical ventilation, length of ICU stay, and survival outcomes were assessed. Statistical analyses were performed via Kaplan—Meier survival analysis and the Cox regression method. Results: Our findings revealed that patients with low potassium and calcium levels had significantly higher mortality rates (p < 0.05). When sodium levels were divided into quartiles, mortality risk markedly increased in both the lowest (Q1) and highest (Q4) quartiles. Cox regression analysis revealed that the mortality risk in hyponatremic patients was 2.2 times greater than that in normonatremic patients (p = 0.005). In the hyponatremic group, the increased mortality risk was statistically borderline significant (p = 0.06). In the logistic regression analysis conducted to evaluate ICU mortality, which included all electrolyte levels and clinical scoring systems, higher APACHE II and SOFA scores were identified as significant risk factors for ICU mortality. Conversely, the presence of COPD was found to be relatively protective compared with other underlying causes of respiratory failure in terms of mortality. Conclusions: Electrolyte imbalances are important predictors of mortality in patients with respiratory failure. Sodium levels exhibit a “U-shaped” relationship with mortality, with hyponatremia emerging as a prominent risk factor. Careful assessment of electrolyte imbalances is crucial in the clinical management of these patients. Full article

Organic electroactive materials (OEMs) offer advantages such as cost-effectiveness, environmental sustainability, and simplified end-of-life processing compared to inorganic electrode materials. Aqueous electrolytes further enhance sustainability and safety relative to organic electrolytes. Investigating the electrochemical properties of OEMs in aqueous media provides valuable insights into their redox behavior and stability under such conditions. However, challenges remain, including low electronic conductivity and structural stability concerns, while aqueous rechargeable batteries (ARBs) face inherent energy density limitations. Tetrathiafulvalene (TTF) has been previously reported as an electrode material for ARBs, while its oligomers have been proposed for organic electrolyte batteries. This study focuses on the synthesis and characterization of two new dissymmetric TTF derivatives—cyanobenzene tetrathiafulvalene pyrazine (CNB-TTF-Pz) (1) and 4-cyanobenzene tetrathiafulvalene pyrazine (4-CNB-TTF) (2)—as well as one symmetric TTF derivative, dipyrazine tetrathiafulvalene ((Pz)₂-TTF) (3). Their electrochemical behavior in aqueous lithium and potassium nitrate electrolytes was systematically characterized using cyclic voltammetry. The study provides insights into the redox properties and electroactivity of these compounds, highlighting challenges related to low electronic conductivity and redox potentials close to the water stability limits. These findings contribute to broadening our understanding of the electrochemical properties of TTF derivatives in aqueous electrolytes and offer a preliminary assessment of their potential application as electrodes for ARBs. Full article

This study aims to achieve in situ-formed pure Ti and Ti6Al4V coatings on 316L stainless steel through hot pressing and examine their wear and corrosion properties thoroughly in two simulated body fluids: physiological serum (0.9% NaCl) and Hanks’ solution. The sintering and diffusion bonding process was conducted at 1050 °C under a uniaxial pressure of 40 MPa for 30 min in a vacuum environment of 10⁻⁴ mbar. Following sintering, in situ-formed pure Ti and Ti6Al4V coatings, approximately 1000 µm thick, were produced on 316L substrates approximately 3000 µm in thickness. The mean hardness of 316L substrates, pure Ti, and Ti6Al4V coatings are around 165 HV, 170 HV, and 420 HV, respectively. The interface of the stainless steel substrate and the pure Ti and Ti6Al4V coatings exhibited no microstructural defects, while the interface exhibited significantly higher hardness values (ranging from 600 to 700 HV). The coatings improved corrosion resistance in both electrolytes compared to the 316L substrate. Wet wear tests revealed reduced friction coefficients in 0.9% NaCl relative to Hanks’ solution, highlighting the chemical interactions between the material surface and the electrolyte type and the significance of tribocorrosion in biocoatings. Full article

Lithium metal batteries (LiMBs) have emerged as extremely viable options for next-generation energy storage owing to their elevated energy density and improved theoretical specific capacity relative to traditional lithium batteries. However, safety concerns, such as the flammability of organic liquid electrolytes, have limited their extensive application. In the present study, we utilize molecular dynamics and Density Functional Theory based simulations to investigate the Li interactions in gel polymer electrolytes (GPEs), composed of a 3D cross-linked polymer matrix combined with two different non-flammable electrolytes: 1 M lithium hexafluorophosphate (LiPF₆) in ethylene carbonate (EC)/dimethyl carbonate (DMC) and 1 M lithium bis(fluorosulfonyl)imide (LiFSI) in trimethyl phosphate (TMP) solvents. The findings derived from radial distribution functions, coordination numbers, and interaction energy calculations indicate that Li⁺ exhibits an affinity with solvent molecules and counter-anions over the functional groups on the polymer matrix, highlighting the preeminent influence of electrolyte components in Li⁺ solvation and transport. Furthermore, the second electrolyte demonstrated enhanced binding energies, implying greater ionic stability and conductivity relative to the first system. These findings offer insights into the Li⁺ transport mechanism at the molecular scale in the GPE by suggesting that lithium-ion transport does not occur by hopping between polymer functional groups but by diffusion into the solvent/counter anion system. The information provided in the work allows for the improvement of the design of electrolytes in LiMBs to augment both safety and efficiency. Full article

As global climate change escalates, horticultural crops, especially walnuts, face increased vulnerability to frost damage. Cold hardiness—a crucial trait for survival—is influenced by complex physiological and biochemical mechanisms. This study assessed the cold hardiness of five walnut cultivars—‘Xinxin 2’, ‘Wen 81’, ‘Wen 185’, ‘Zha 343’, and ‘Xinzaofeng’—under simulated low-temperature stress, focusing on differences in freezing tolerance. One-year branches were gradually cooled to temperatures as low as −30 °C. Key physiological metrics, including electrolyte leakage (EL) and regrowth (RG) potential, along with biochemical metrics like antioxidant enzyme activities and osmoregulatory compounds, were used to evaluate cold hardiness. A comprehensive cold resistance indicator, derived using the subordination function method, highlighted cultivar resilience. Results showed significant variation in cold tolerance, with ‘Wen 185’ and ‘Wen 81’ exhibiting superior resilience, while ‘Xinxin 2’ was the most susceptible. Logistic regression analysis of relative electrolyte conductivity (REC) data estimated the semi-lethal temperature (LT50), identifying ‘Wen 81’ as the most cold-tolerant cultivar (LT50 = −21.73 °C). Antioxidant enzymes and osmoregulatory compounds were crucial for maintaining cellular stability and recovery after freezing. These findings offer practical insights for breeding cold-resistant cultivars and strategies to mitigate frost damage. Full article

Lithium-conducting NASICON materials have emerged as a promising alternative to organic liquid electrolytes for high-energy-density Li-metal batteries, owing to their superior ionic conductivity and excellent air stability. However, their practical application is hindered by poor sintering characteristics and high grain boundary resistance. In this investigation, Li_1.3Al_0.3−xY_xTi_1.7(PO₄)₃ (LAYTP-x, x = 0.00, 0.01, 0.03, 0.05, and 0.07) were successfully synthesized via conventional solid-state reaction to explore the impact of Y³⁺ on both ionic conductivity and chemical stability. The structural, morphological, and transport properties of the samples were comprehensively characterized in order to identify the optimal doping concentration. All samples exhibited a NASICON structure with a uniform distribution of Y elements within the electrolyte. Due to its highest relative density (95.8%), the LAYTP-0.03 electrolyte demonstrated the highest total conductivity of 2.03 × 10⁻⁴ S cm⁻¹ with a relatively low activation energy of 0.33 eV, making it suitable for solid-state batteries. When paired with the NCM811 cathode, the Li/LAYTP-0.03/NCM811 cell exhibited outstanding electrochemical performance: a high capacity of 155 mAh/g was achieved at 0.2C after 50 cycles with a Coulombic efficiency of approximately 100%, indicating highly reversible lithium plating/stripping facilitated by the LAYTP-0.03 electrolyte. These results suggest that the LAYTP-0.03 ceramic electrolyte could be a promising alternative for developing safe solid-state Li-metal batteries. Full article

Solid-state electrolytes for lithium-ion batteries, which enable a significant increase in storage capacity, are at the forefront of alternative energy storage systems due to their attractive properties such as wide electrochemical stability window, relatively superior contact stability against Li metal, inherently dendrite inhibition, and a wide range of temperature functionality. NASICON-type solid electrolytes are an exciting candidate within ceramic electrolytes due to their high ionic conductivity and low moisture sensitivity, making them a prime candidate for pure oxidic and hybrid ceramic-in-polymer composite electrolytes. Here, we report on producing pure and Y-doped Lithium Aluminum Titanium Phosphate (LATP) nanoparticles by spray-flame synthesis. The as-synthesized samples consist of an amorphous component and anatase-TiO₂ crystalline particles. Brief annealing at 750–1000 °C for one hour was sufficient to achieve the desired phase while maintaining the material’s sub-micrometer scale. Rietveld analysis of X-Ray diffraction data demonstrated that the crystal volume increases with Y doping. At the same time, with high Y incorporation, a segregation of the YPO₄ phase was observed in addition to the desired LATP phase. Another impurity phase, LiTiOPO₄, was observed besides YPO₄ and, with higher calcination temperature (1000 °C), the phase fraction for both impurities also increased. The ionic conductivity increased with Y incorporation from 0.1 mS/cm at room temperature in the undoped sample to 0.84 mS/cm in the case of LAY0.1TP, which makes these materials—especially considering the comparatively low sintering temperature—highly interesting for applications in the field of solid-state batteries. Full article

Solid-state batteries (SSBs) have been recognized as promising energy storage devices for the future due to their high energy densities and much-improved safety compared with conventional lithium-ion batteries (LIBs), whose shortcomings are widely troubled by serious safety concerns such as flammability, leakage, and chemical instability originating from liquid electrolytes (LEs). These challenges further deteriorate lithium metal batteries (LMBs) through dendrite growth and undesirable parasitic reactions. Polymer electrolytes (PEs) have been considered among the few viable options that have attracted great interest because of their inherent non-flammability, excellent flexibility, and wide electrochemical stability window. However, practical applications are seriously limited due to the relatively low ionic conductivity, mechanical instability, and short operational life cycle. This review covers the recent developments in the field and applications of polymer electrolytes in SSBs, including solid polymer electrolytes (SPEs), gel polymer electrolytes (GPEs), and composite polymer electrolytes (CPEs). The discussion comprises the key synthesis methodologies, electrochemical evaluation, and fabrication of PEs while examining lithium-ion’s solvation and desolvation processes. Finally, this review highlights innovations in PEs for advanced technologies like lithium metal batteries and beyond, covering emerging trends in polymer materials and advancements in PE performance and stability to enhance commercial applications. Full article