Search Results (127)

Redox-flow batteries are a promising emerging technology for large-scale storage of renewable energy. However, existing ion-exchange membranes used for separating electrolytes are expensive and often ineffective at preventing crossover of redox-active species, leading to a decrease in battery capacity over time. Herein, we introduce a new class of proton-conducting membranes formed by depositing highly alkylated waxy hydrophobic salts on porous polypropylene supports and demonstrate that they form self-assembled nanostructures which exclusively conduct protons via a unique mechanism of action. These new “ionowax” membranes display comparable proton conductivities to existing commercially available functionalized porous polymer membranes but are cheaper and easier to fabricate. We anticipate that these new membranes will facilitate future development of cheaper and/or longer-lasting aqueous redox-flow batteries. Full article

Electrochemical carbon dioxide reduction reaction (CO₂RR) offers a promising route to mitigate climate change while simultaneously enabling renewable energy storage and the sustainable production of value-added chemicals. A wide variety of CO₂RR reactor designs have been developed, including both liquid-phase cells and gas-phase configurations. Among these, gas-phase systems, particularly flow-cell and membrane electrode assembly (MEA) designs, have become the primary focus of recent research due to their ability to overcome mass transport limitations and operate at high currents. While catalyst development has received considerable attention in advancing CO₂RR performance, the role of membranes in these gas-phase electrolyzers has been less systematically reviewed. This article addresses that gap by critically examining the functions, advantages, and limitations of the major membrane classes used in CO₂ electrolysis: anion exchange membranes, cation exchange membranes, bipolar membranes, and non-ion-exchange porous membranes within flow-cell and MEA configurations. We highlight how membrane properties influence local pH regulation, water management, crossover behavior, and overall reactor performance, while emphasizing that product identity is primarily catalyst-determined. By analyzing recent progress and remaining challenges, this review provides design insights for membrane selection and development toward efficient, stable, and scalable CO₂ electrolysis systems. Full article

In this study, we investigate temperature fluctuations in hot QCD matter using a three-flavor Polyakov loop-extended Nambu–Jona-Lasinio (PNJL) model. The high-order cumulant ratios $R_{n2}$ ($n>2$) exhibit non-monotonic variations across the chiral phase transition, characterized by slight fluctuations in the chiral crossover region and significant oscillations around the critical point. In contrast, distinct peak and dip structures are observed in the cumulant ratios at low-baryon chemical potential. These structures gradually weaken and eventually vanish at high chemical potential as they compete with the sharpening of the chiral phase transition, particularly near the critical point and the first-order phase transition. Our results indicate that these non-monotonic peak and dip structures in high-order cumulant ratios are associated with the deconfinement phase transition. This study quantitatively analyzes temperature fluctuation behavior across different phase transition regions, and the findings are expected to be observed and validated in heavy-ion collision experiments through measurements of event-by-event mean transverse momentum fluctuations. Full article

Polyampholytes combine cationic and anionic groups in one macromolecular platform and are emerging as versatile components for energy storage and conversion. This review synthesizes how their charge balance, hydration, and architecture can be engineered to address ionic transport, interfacial stability, and safety across batteries, supercapacitors, solar cells, and fuel cells. We classify annealed, quenched, and zwitterionic systems, outline molecular design strategies that tune charge ratio, distribution, and crosslinking, and compare device roles as gel or solid electrolytes, eutectogels, ionogels, binders, separator coatings, and interlayers. Comparative tables summarize ionic conductivity, cation transference number, electrochemical window, mechanical robustness, and temperature tolerance. Across Li and Zn batteries, polyampholytes promote ion dissociation, homogenize interfacial fields, suppress dendrites, and stabilize interphases. In supercapacitors, antifreeze hydrogels and poly(ionic liquid) networks maintain conductivity and elasticity under strain and at subzero temperature. In solar cells, zwitterionic interlayers improve work function alignment and charge extraction, while ordered networks in fuel cell membranes enable selective ion transport with reduced crossover. Design rules emerge that couple charge neutrality with controlled hydration and dynamic crosslinking to balance conductivity and mechanics. Key gaps include brittleness, ion pairing with multivalent salts, and scale-up. Opportunities include soft segment copolymerization, ionic liquid and DES plasticization, side-chain engineering, and operando studies to guide translation. Full article

In order to solve the problems of mass transfer polarization spatiotemporal distribution variations, uncontrollable regulation error, and accelerated capacity decay caused by ion crossover in high-power vanadium liquid flow batteries (VFBs), a three-dimensional battery model with a flow-type flow field based on the three-dimensional transient COMSOL Multiphysics^® 6.1 numerical modeling method was developed in this study. The model combines the ion transmembrane migration equation with the mass transfer polarization theory, constructs an objective function to quantify the regulation error, and is validated by multifluid-field structural simulations. The results indicate the following: (1) Ion crossover induces a 3–5% electrolyte concentration deviation and a current density distribution bias reaching 11%; (2) The intensity of mass transfer polarization exhibits a linear increase with the flow rate difference between the positive and negative electrodes; (3) Ion crossover significantly degrades system performance, causing Coulombic efficiency (CE) and Energy efficiency (EE) to decrease by 1.1% and 1.5%, respectively. This research demonstrates that unlike conventional flow field optimization, our strategy quantifies the regulation error by directly compensating for the ΔQ caused by ion crossing, and further regulation minimizes the effect, providing a theoretical basis for mass transfer intensification and capacity recovery in flow batteries. Full article

Amyotrophic lateral sclerosis (ALS) is a fatal type of neurodegenerative disease marked by progressive and selective degeneration of motor neurons (MNs) present in the spinal cord, brain stem and motor cortex. However, the intricate molecular mechanisms underlying primary cell death pathways, including ferroptosis-related genes (FRGs) mediating MN dysfunction in ALS, remain elusive. Ferroptosis, a novel type of iron-dependent cell death with the accumulation of lipid peroxidation products, stands distinct from apoptotic-related stress and other cell death mechanisms. Although growing advances have highlighted the role of iron deposition, apoptosis and alteration of antioxidant systems in ALS pathogenesis, there is little data at the systems biology level. Therefore, we performed a comprehensive bioinformatic analysis of bulk RNA-sequencing (RNA-seq) data by systematically comparing the gene expression profiles from iPSC-derived MNs of ALS patients and healthy controls using our datasets as well as from the GEO database to reveal the role of ferroptosis-related gene alterations in ALS, especially in selective MN vulnerability of FUSED IN SARCOMA (FUS) mutations. In this study, we first identified differentially expressed genes (DEGs) between FUS mutant and healthy controls. Subsequently, the crossover genes between DEGs and FRGs were selected as differentially expressed ferroptosis-related genes (DEFRGs). Functional enrichment and protein–protein interaction (PPI) analysis of DEFRGs identified that DNA damage, stress response and extra cellular matrix (ECM) were the most significantly dysregulated functions/pathways in FUS-ALS causing mutations compared to healthy controls. While GSEA analysis showed enrichment of genes associated with apoptosis, the degree of ferroptosis and iron ion homeostasis/response to iron of FUS MNs was lower. Altogether, our findings may contribute to a better understanding of the relevant role of cell death pathways underlying selective vulnerability of MNs to neurodegeneration in FUS-ALS pathophysiology. Full article

We calculate the Doniach phase diagram of heavy-fermion systems containing Ce and Eu ions, using the scaling solution of the periodic Anderson model, and compare the results with the experimental data on CeRu₂Ge₂ and EuCu₂(Ge_1−xSi_x)₂. The temperature–pressure (T–p) phase diagram emerges from the competition between the pressure-dependent Kondo interaction and the temperature- and pressure-dependent RKKY interaction. Both are derived using scaling equations in the presence of crystal-field effects: Kondo temperature $T_K$ is related to the coupling constant g(p), where p is the control parameter, and the temperature-dependent renormalized coupling $g(T,T_K(g))$. For comparison with the experiment, we assume a linear dependence of g on the control parameter, which could be pressure or composition. The Néel temperature $T_N(p)$ is obtained by comparing the free energies of the system in the antiferromagnetic and paramagnetic states. The resulting asymmetric $T_N(p)$ arises naturally from the exponential growth of $T_K(p)$ and a much slower polynomial growth of the RKKY interaction. Phase diagrams for CeRu₂Ge₂ and EuCu₂(Ge_1−xSi_x)₂ successfully capture key experimental features: pressure-induced suppression of magnetic order, the peak of RKKY interaction energy, and crossover to a heavy-Fermi-liquid regime at high coupling strength. Our work provides the first quantitative, material-specific construction of Doniach diagrams, clarifies the entropy removal at low temperatures and offers predictive insight for future experiments under extreme conditions. Full article

Background: Crystalline glucosamine sulfate (cGS) claims to be a stabilized form of glucosamine sulfate with a defined crystalline structure intended to enhance chemical stability. It is proposed to offer pharmacokinetic advantages over regular glucosamine sulfate (rGS) which is stabilized with potassium or sodium chloride. However, comparative human bioavailability data are limited. Since both forms dissociate in gastric fluid into constituent ions, the impact of cGS formulation on absorption remains uncertain. This pilot study aimed to compare the bioavailability of cGS and rGS using a randomized, double-blind, crossover design. Methods: Ten healthy adults received a single 1500 mg oral dose of either cGS or rGS with a 7-day washout between interventions. Capillary blood samples were collected over 24 h. Glucosamine and its metabolite concentrations were quantified by Liquid Chromatography-High Resolution Mass Spectrometry (LC-HRMS), and pharmacokinetic parameters—including maximum concentration (C_max), time to reach C_max (T_max), and area under the curve (AUC)—were calculated. Results: Mean AUC_0–24, C_max, T_max, and T_½ values for glucosamine and glucosamine-6-sulfate (GlcN-6-S) were comparable between cGS and rGS. Although the AUC_0–24 for glucosamine was modestly higher with rGS (18,300 ng·h/mL) than with cGS (12,900 ng·h/mL), the difference was not statistically significant (p = 0.136). GlcN-6-S exposure was also similar between formulations (rGS: 50,700 ng·h/mL; cGS: 50,600 ng·h/mL), with a geometric mean ratio of 1.39, a delayed T_max (6–8 h) and longer half-life, consistent with its role as a downstream metabolite. N-acetylglucosamine levels remained stable, indicating potential homeostatic regulation. Conclusions: This pilot study found no significant pharmacokinetic advantage of cGS over rGS. These preliminary findings challenge claims of cGS’ pharmacokinetic superiority, although the small sample size limits definitive conclusions. Larger, adequately powered studies are needed to confirm these results. Full article

Alkaline electrolytic water hydrogen generation, a key driver in the growth of hydrogen energy, heavily relies on high-efficiency and high-purity ion exchange membranes. In this study, three-dimensional (3D) wrinkled reduced graphene oxide (WG) nanosheets obtained through a simple thermal reduction process and two-dimensional (2D) graphene oxide act as building blocks, with ethylenediamine as a crosslinking stabilizer, to construct a unique 3D/2D 2 nm-tunneling structure between the GO and WG sheets through via an amide connection at a WG/GO ratio of 1:1. Here, the wrinkled graphene (WG) undergoes a transition from two-dimensional (2D) graphene oxide (GO) into three-dimensional (3D) through the adjustment of surface energy. By increasing the interlayer spacing and the number of ion fluid channels within the membranes, the E-W/G membrane has achieved the rapid passage of hydroxide ions (OH⁻) and simultaneous isolation of produced gas molecules. Moreover, the dense 2 nm nano-tunneling structure in the electrolytic water process enables the E-W/G membrane to attain current densities >99.9% and an extremely low gas crossover rate of hydrogen and oxygen. This result suggests that the as-prepared membrane effectively restricts the unwanted crossover of gases between the anode and cathode compartments, leading to improved efficiency and reduced gas leakage during electrolysis. By enhancing the purity of the hydrogen production industry and facilitating the energy transition, our strategy holds great potential for realizing the widespread utilization of hydrogen energy. Full article

AQ suspensions show strong potential as organic anodes for Li-ion slurry batteries. However, the influence of slurry electrolyte composition on the electrochemical behavior of AQ lacks systematic investigation. We explored the effects of different lithium salts and solvents in the electrolyte on the redox behavior of the AQ material electrode. An electrolyte (1 M LiTFSI dissolved in DME: DOL with a volume ratio of 1:1) optimized for AQ lithium slurry batteries exhibits a stable 2.3 V charge/discharge platform delivering a discharge specific capacity of 246.2 mAh g⁻¹ at 1.25 A g⁻¹ (approaching the theoretical value) with stable slurry reactor operation for over 47 h. This work establishes a structure-property relationship between electrolyte formulation and AQ electrode performance, offering a design principle for electrolyte selection in organic slurry-based battery systems. Full article

The heteroleptic halogen-substituted Fe³⁺ complex of formula [FeL₂Bipy]Cl, where L is 1-(4-fluoro-phenyl)-3-(4-bromo-phenyl)-propane-1,3-dione and Bipy is 2,2′-bipyridine, was synthesized, and its optic and magnetic properties were studied. Magnetic measurements showed that the complex at high temperatures (T > 75 K) is predominantly in the high-spin (HS) state of Fe³⁺ ions (S = 5/2, γ_HS¹ = 93%) with a small admixture of low-spin (LS) state (S = 1/2, γ_LS¹ = 7%). At T* ≈ 46 K, a partial spin-crossover transition (SCO, 5/2↔1/2) occurs. This process is accompanied not only by a change in the magnetic state (γ_HS² = 76%, γ_LS² = 24%), but also by the appearance of AFM interactions (θ_II = −2.3 K) between neighboring Fe³⁺ ions. A theoretical model was proposed to describe magnetic susceptibility, χ(T). As a result of the analysis of the ground spin state M(H) at 2.0 K, it was established that the majority of the LS states, as well as part of the HS states of Fe³⁺ ions (γ_HS ~ 53%), do not participate in exchange interactions. EPR studies confirmed the presence of HS and LS Fe³⁺ centers and made it possible to isolate I-type and II-type HS centers, corresponding to strong low-symmetry and weak distorted octahedral fields. SCO was also detected and the temperature dependences of the EPR intensities, I(T), of the HS and LS centers were analyzed. Full article

The copper redox flow battery (CuRFB) stands out as a promising hybrid redox flow battery technology, offering significant advantages in electrolyte stability. Within the CuBER H-2020 project framework, this study addresses critical phenomena such as electrodeposition at the negative electrode during charging and copper crossover through the membrane, which influence capacity fading. A comprehensive two-dimensional physicochemical model of the CuRFB cell was developed using COMSOL Multiphysics, providing insights into the distribution of electroactive materials over time. The model was validated against experimental cycling data, demonstrating a Root Mean Square Error (RMSE) of 0.0212 in voltage estimation. Least-squares parameter estimation, utilizing Bound Optimization by Quadratic Approximation, was conducted to determine active material diffusivities and electron transfer coefficients. The results indicate that higher current densities and lower flow rates lead to increased copper deposition near the inlet, significantly impacting the battery’s State of Health (SoH). These findings highlight the importance of considering fluid dynamics and ion concentration distribution to improve battery performance and longevity. The study’s insights are crucial for optimizing and scaling up CuRFB operations, guiding potential cell-scale-up strategies into stack-level configurations. Full article

The proton exchange membrane (PEM) is a critical component of fuel cells, responsible for controlling the flow of protons while minimizing fuel crossover through its channels. The commercial membrane commonly used in fuel cells is made of Nafion, which is expensive and prone to swelling when in contact with water. To address these limitations, various polymers have been explored as alternatives to replace the costly Nafion membrane. Styrene, a versatile and cost-effective material, has emerged as a promising candidate. It can be modified into different forms to meet the requirements of a fuel cell membrane. The aromatic rings in styrene can copolymerize with hydrophilic functional groups, enhancing water (H₂O) uptake, proton conductivity, and ion exchange capacity (IEC) of the membrane. Additionally, the hydrophobic nature of styrene helps maintain the structural integrity of the membrane’s channels, reducing excessive swelling and minimizing fuel crossover. The flexible aromatic chains in styrene facilitate the attachment of hydrophilic functional groups, such as sulfonic groups, further improving the membrane’s ion conductivity, IEC, thermal stability, mechanical strength, and oxidative stability. This review article explores the application of styrene and its derivatives in fuel cell membranes, with a focus on proton exchange membrane fuel cells (PEMFCs), direct methanol fuel cells (DMFCs), and anion exchange membrane fuel cells (AEMFCs). Full article

The 2,6-bis(pyrazol-1-yl)pyridine (bpp) ligand family is widely recognized for its versatile coordination abilities and broad functionalization potential. This review examines bpp and its modifications at the pyridine ring’s 4-position, focusing on their influence on magnetic, optical, and electronic properties. Key applications discussed include spin crossover (SCO), single-ion and single-molecule magnetism (SIM and SMM), luminescence, redox flow batteries (RFBs), and photonic devices. We provide a comprehensive overview of ligand modifications involving carboxylates, extended aromatic systems, radicals, and redox-active units such as tetrathiafulvalene (TTF), alongside supramolecular architectures. The review highlights fundamental design principles, particularly the role of substituents in tuning the SCO behavior, photophysical properties, and self-assembly into functional nanostructures. Notable advancements include SCO-driven conductivity modulation, reversible luminescent switching, and amphiphilic bpp-based vesicles for multicolor emission. By analyzing the interplay between ligand structure and magnetic, optical, and electronic functions, we provide insights into the potential of bpp derivatives for advanced materials design. This review presents recent experimental and theoretical developments, offering a foundation for future exploration of bpp-based compounds in multifunctional devices. Full article

Experimental protocols based on Electron Paramagnetic Resonance (EPR) and Raman spectroscopy are presented for the investigation of the Fe(II) spin transition in Cu(II)-doped 1-D spin-crossover (SCO) nanoparticles of the type [Fe_1−xCu_x(NH₂trz)₃]Br₂ where x = 0.03 and 0.06 and NH₂trz = 4-amino-1, 2, 4-triazole. The resulting nanoparticles were characterized using Transmission Electron Microscopy (TEM), Infrared (IR) spectroscopy, and powder X-ray diffraction (p-XRD). Magnetic susceptibility measurements revealed a dependence on the scan rate, with critical temperatures and hysteresis widths varying accordingly. EPR spectroscopy provided insights into the doped nanoparticles’ structural changes and spin-state transitions. The Cu(II) dopants exhibited significant g-factor anisotropy and hyperfine structure, indicative of a distorted octahedral coordination. The EPR spectra indicated that the spin transition occurs in domains populated by ions of the same spin state. Cu(II) ions show different spectral characteristics depending on whether they are in high-spin or low-spin domains of Fe(II). Changes in Raman bands induced by laser power reveal structural and electronic rearrangements during the LS to HS transition. The findings provide insights into metal–ligand interactions and the molecular mechanisms underlying the SCO process. Full article