Choice Of Solvent Research Articles

Molecular precursors for the electrodeposition of 2D-layered metal chalcogenides.

Two-dimensional transition metal dichalcogenides (TMDCs) are highly anisotropic, layered semiconductors, with the general formula ME2 (M = metal, E = sulfur, selenium or tellurium). Much current research in this fieldfocusses on TMDCs for catalysis and energy applications; they are also attracting great interest for next-generation transistor and optoelectronic devices. Thelatter high-tech applications place stringent requirements on the stoichiometry, crystallinity, morphology and electronic properties of monolayer and few-layer materials. As a solution-based process, wherein the material grows specifically on the electrode surface, electrodeposition offers great promise as a readily scalable, area-selective growth process. This Review explores the state-of-the-art for TMDC electrodeposition, highlighting how the choice of precursor(or precursors), solvent and electrode designs, with novel 'device-ready' electrode geometries, influence their morphologies and properties, thus enabling the direct growth of ultrathin, highly anisotropic 2D TMDCs and much scope for future advances.

3D Printing Organogels with Bioderived Cyrene for High-Resolution Customized Hydrogel Structures.

3D printing techniques are increasingly being explored to produce hydrogels, versatile materials with a wide range of applications. While photopolymerization-based 3D printing can produce customized hydrogel shapes and intricate structures, its reliance on rigid printing conditions limits material properties compared to those of extrusion printing. To address this limitation, this study employed an alternative approach by printing an organogel precursor using vat polymerization with organic solvents instead of water, followed by solvent exchange after printing to create the final hydrogel material. Using mask stereolithography (mSLA), we evaluated the effects of solvent choice on a novel and recently developed 3D-printed supramolecular hydrogel, cross-linked with quaternized chitosan/acrylate salt. In this study, we compared the conventional solvent dimethyl sulfoxide (DMSO) with the bioderived solvent Cyrene. Our findings reveal that hydrogels produced with Cyrene-based 3D printing exhibit weaker strength but high swelling capacity and elasticity, resilience to cyclic loading, and the ability to produce detailed and accurate 3D-printed objects. These results provide insights into the solvent-dependent mechanical and physical characteristics of 3D-printed hydrogels and underscore the potential of Cyrene as a sustainable alternative for polymeric synthesis.

Room-temperature synthesis of highly luminescent methylammonium lead bromide nanocubes encapsulated in block copolymer micelles: impact of solvent choice on crystallization and stability

The choice of solvent (methanol and DMF) for transporting MA+ and Br− ions from the TMB phase to the micelle core significantly influences the dimensions of the resulting MAPbBr3 perovskite.

The swelling mechanism of ethylene-vinyl acetate polymer in different solvents via molecular dynamics and experimental studies.

Ethylene-vinyl acetate (EVA) film is the predominant encapsulation material in crystalline silicon photovoltaic modules, the efficient and eco-friendly processing of which is essential for the recycling of the modules. Among the various existing techniques, the chemical approach uses solvents to induce swelling and dissolution on the EVA film to facilitate the separation of distinct layers. This method demonstrates the potential for achieving low-energy consumption and minimal-damage retrieval of the diverse materials within the components. Nonetheless, the mechanism underlying the swelling of the EVA polymer and the consequent delamination of various layers remains elusive, hindering the proper choice of solvents. In this study, the swelling behaviors of the EVA polymer in water, ethanol, and D-limonene solvents were analyzed via molecular dynamics (MD) simulations. The influence of intermolecular interactions on the swelling degree of the EVA polymers had been examined to determine the dominant factors leading to the discrepancies in the diffusion state of EVA in different solvents. The molecular electrostatic potential (MEP) maps were utilized to explain the differences in interactions from a molecular structure perspective. Furthermore, the results of MD simulations were experimentally verified by solvent-immersion experiments and testing methods. Based on the results, the swelling mechanism of the EVA polymer in the selected solvents was proposed and illustrated, providing theoretical support for chemically-driven photovoltaic module recycling processes.

Spatial specificity of radical scavenging ability in Moringa oleifera varieties from selected countries

Moringa oleifera (MO) is widely recognized for its rich content of bioactive compounds, which possess significant antioxidant and anti-inflammatory properties. However, variations in the phytochemical composition of MO seeds, influenced by geographical origin and processing methods, have not been fully explored. This study investigates the radical scavenging abilities of MO seeds from Nigeria, Ghana, Haiti, and India, all grown under controlled conditions at the Winfred Thomas Agricultural Research Station (WTARS) at Alabama A and M University. The primary objective of this study was to assess the variation in radical scavenging abilities, specifically DPPH (1,1-diphenyl-2-picrylhydrazyl) activity, across different MO seed varieties and processing methods. This was done to determine if spatially specific dose-response behaviors exist and to identify which combinations of seed origin and preparation yield the highest antioxidant activity. MO seeds were collected from four countries: Nigeria, Ghana, Haiti, and India, and subjected to three different processing methods—raw, boiled, and fermented. The seeds were then extracted using two solvents, 70% ethanol and 80% methanol. The DPPH radical scavenging activity was measured using the Brand-Williams method with slight modifications, and the results were expressed as micromoles of Trolox Equivalent (TE) per gram of sample. The study revealed significant variability in the antioxidant activity of MO seeds based on their geographical origin and processing methods. Among the four countries, MO seeds from India exhibited the highest average DPPH value (8018.87 µmol/g), followed by Haiti (6741.10 µmol/g), Nigeria (6349.98 µmol/g), and Ghana (6068.87 µmol/g). Raw seeds consistently showed the highest radical scavenging ability across all locations and solvents, with the highest recorded value in Haitian raw seeds extracted with 70% ethanol (9720 µmol/g). In contrast, fermented seeds exhibited the lowest antioxidant activity, with the least value observed in Ghanaian seeds extracted with 80% methanol (306.33 µmol/g). The choice of solvent also played a crucial role, with 70% ethanol outperforming 80% methanol in preserving or extracting antioxidants, particularly in raw and boiled seeds. The study also found significant dose-response relationships, with raw seeds showing the steepest increase in DPPH activity with higher extract concentrations. In contrast, fermented seeds demonstrated a weaker dose-response, indicating diminished radical scavenging ability after fermentation. The ANOVA results further highlighted the significant effects of the country of origin, treatment method, and their interaction on antioxidant activity. The interaction between geographical origin and processing methods was particularly noteworthy, suggesting that the optimal method for maximizing antioxidant activity varies depending on the seed's origin. The findings underscore the importance of considering both the geographical origin and the processing method when evaluating the antioxidant properties of MO seeds. Indian and Haitian MO seeds, particularly in their raw form and extracted with 70% ethanol, offer the highest antioxidant potential. The study also demonstrates that minimal processing is crucial for preserving the radical scavenging ability of MO seeds. Further research should focus on the specific phytochemical compounds responsible for the antioxidant activity in MO seeds from different regions. Additionally, farmers and producers should optimize cultivation and processing methods based on local environmental conditions to maximize the nutritional and medicinal benefits of MO seeds. Finally, public awareness programs should be initiated to promote the health benefits of MO seeds, particularly those with high antioxidant activity.

A novel recyclable hydrolyzed nanomagnetic copolymer catalyst for green, and one-pot synthesis of tetrahydrobenzo[b]pyrans

Polymer-based catalysts have garnered significant interest for their efficiency, reusability, and compatibility with various synthesis processes. In catalytic applications, polymers offer the advantage of structural versatility, enabling functional groups to be tailored for specific catalytic activities. In this study, we developed a novel magnetic copolymer of methyl methacrylate and maleic anhydride (PMMAn), synthesized via in situ chemical polymerization of methyl methacrylate onto maleic anhydride, using benzoyl peroxide as a free-radical initiator. This polymerization process results in a robust copolymer matrix, which was subsequently hydrolyzed in an alkaline aqueous solution to introduce additional functional groups, yielding hydrolyzed PMMAn. These functional groups enhance the copolymer’s ability to support the deposition of magnetic nanoparticles and participate in catalytic reactions. Following hydrolysis, we fabricated a unique magnetic composite, Fe3O4@Hydrol-PMMAn, by in situ coprecipitating Fe3O4 nanoparticles onto the hydrolyzed copolymer, creating a stable nanocatalyst. The structural and magnetic properties of Fe3O4@Hydrol-PMMAn were thoroughly analyzed using FTIR, XRD, SEM, EDX, VSM, and TGA. The Fe3O4@Hydrol-PMMAn nanocatalyst demonstrated remarkable catalytic performance in synthesizing tetrahydrobenzo[b]pyran derivatives through a three-component reaction, conducted without solvents to support green chemistry principles. A series of reaction parameters were optimized, including solvent choice, catalyst loading, and recyclability. The catalyst performed efficiently across a broad range of aldehydes, delivering high product yields (81–96%) with rapid reaction times (5–30 min) at a low catalyst loading of 0.015 g. A hot filtration test confirmed the heterogeneous nature of the nanocatalyst, which could be recycled up to four cycles with minimal loss in activity. The high yield, short reaction time, solvent-free conditions, and excellent reusability make Fe3O4@Hydrol-PMMAn a promising catalyst. These findings underscore its potential for converting waste products into valuable compounds, highlighting its utility in organic transformations and sustainable synthesis practices. Collectively, this work demonstrates that Fe3O4@Hydrol-PMMAn is highly effective for organic compound synthesis, advancing the development of versatile, sustainable nanocatalysts.

Solvents and their hydrogen bonding properties as general considerations in carbon dioxide reduction by molecular catalysts.

Improvements to the understanding of how reaction conditions influence the performance of molecular electrocatalysts are important. There exists a wide range of solution conditions that are used in the investigation of the properties and performance of electrocatalysts, from the choice of solvent or electrolyte to the identity and nature of other additives, like Brønsted acids. Herein, we demonstrate how the choice of solvent can have a significant impact on the observed rate constants for CO2-to-CO conversion by a series of rhenium(I) diimine complexes. In comparison with the observed rate constants in acetonitrile solvent, the use of a strong hydrogen bond-accepting solvent (N,N-dimethylformamide, DMFf) dramatically decreases the observed rate constants in the presence of added phenol (as a proton donor). Based on previous work from our lab and from others, we conclude that such solvent effects are a general phenomenon and are a crucial consideration for investigation of molecular catalysts. Finally, a simple H-bonding model is presented to account for solvent effects in these rhenium(I) CO2 reduction systems. The model is general for H-bonding solvents and Brønsted acids and provides a first principles means to estimate the magnitude of solvent effects on CO2 reduction kinetics.

Lignin Polyurethane Aerogels: Influence of Solvent on Textural Properties.

This study explores the innovative potential of native lignin as a sustainable biopolyol for synthesizing polyurethane aerogels with variable microstructures, significant specific surface areas, and high mechanical stability. Three types of lignin-Organosolv, Aquasolv, and Soda lignin-were evaluated based on structural characteristics, Klason lignin content, and particle size, with Organosolv lignin being identified as the optimal candidate. The microstructure of lignin polyurethane samples was adjustable by solvent choice: Gelation in DMSO and pyridine, with high affinity to lignin, resulted in dense materials with low specific surface areas, while the use of the low-affinity solvent e.g acetone led to aggregated, macroporous materials due to microphase separation. Microstructural control was achieved by use of DMSO/acetone and pyridine/acetone solvent mixtures, which balanced gelation and phase separation to produce fine, homogeneous, mesoporous materials. Specifically, a 75% DMSO/acetone mixture yielded mechanically stable lignin polyurethane aerogels with a low envelope density of 0.49 g cm-3 and a specific surface area of ~300 m2 g-1. This study demonstrates a versatile approach to tailoring lignin polyurethane aerogels with adjustable textural and mechanical properties by simple adjustment of the solvent composition, highlighting the critical role of solvent-lignin interactions during gelation and offering a pathway to sustainable, high-performance materials.

Assessment of synergistic and antagonistic interactions between volatile compounds thymol, carvacrol, and eugenol diluted in solvents against Rhipicephalus microplus in in vitro tests.

The cattle tick Rhipicephalus microplus is prevalent in tropical and subtropical regions, causing substantial economic losses due to its resistance to conventional acaricides. There is an urgent need to identify safe and effective new acaricidal agents. Essential oils and their volatile compounds are promising alternatives. Ensuring the use of optimal solvents or surfactants that do not compromise the acaricidal activity of these compounds during testing is crucial. This study aims to evaluate how compounds thymol, carvacrol and eugenol interact with xylol, methanol, ethanol, acetone, isopropyl alcohol, glycerol, dimethyl sulfoxide, castor oil, propylene glycol, vaseline, and Tween 80® to enhance (or to worse) their acaricidal efficacy against R. microplus. Larval mortality time were compared against one negative control (soybean oil) and two positive controls (commercial pour-on products). The experiments were conducted in 48-well polyethylene plates, with around 100 larvae immersed in 200 μl of each solvent at 100, 50, 25, 12.5, 6.25, 3.125 and 1.56% and diluted in soybean oil or water, according to solubility. Each volatile compound (Thymol, carvacrol and eugenol) was diluted in the tested solvents to assess larval mortality time. Xylol demonstrated the shortest larval mortality time, even at a minimum concentration (p < 0.05). In contrast, liquid vaseline exhibited the longest larval mortality time. When thymol, carvacrol, and eugenol were combined with xylol, they achieved the shortest larval mortality time. Conversely, when diluted in liquid vaseline they exhibited synergistic effects decreasing the mortality time. Tween 80® worsen the efficacy of thymol, carvacrol, and eugenol, resulting in prolonged larval mortality times. These findings emphasize the critical role of solvent selection, indicating the choice of solvent profoundly affects the formulation's effectiveness, directly influencing the activity of the active compounds.

Gold-Catalyzed Access to Pyrrolo- and (Aryl)Indolo-Fused Phenazines.

Novel fused phenazines were synthesized through a combination of gold-catalyzed hydroamination and cascade cyclization reactions towards azaacenes. In total, 30 new compounds were synthesized and investigated with respect to their structural and optoelectronic properties. In solution, these targets exhibit strong green to red emission, with quantum yields of up to 60%. The emission wavelength can be finely adjusted by the choice of solvent due to their solvatochromic behavior, as demonstrated with a representative example.

Synthesis of polyamide-based RO membranes for saline water treatment

Reverse osmosis (RO) technology is a widely used method for converting seawater into fresh water, known for its high efficiency and broad applications. This study focuses on optimizing the synthesis conditions for polyamide (PA) membranes, including the concentrations of m-phenylenediamine (MPD) and trimesoyl chloride (TMC), the choice of solvent, soaking time, and reaction time. FTIR and SEM analysis confirmed the successful synthesis of the PA layer and revealed that the surface morphology of the membrane was significantly influenced by synthesis conditions. Mechanical testing demonstrated that the optimized membranes exhibited high tensile strength (41.18 MPa) and low elongation at break (11.69%), indicating a robust but relatively brittle material. The study determined that the optimal conditions were 1.0 wt.% MPD and 0.1 wt.% TMC, hexane as a solvent, a soaking time of 2 min, and a reaction time of 60 sec, achieving a maximum salt rejection of 86.45%. These findings are critical for enhancing RO membrane efficiency and addressing the global demand for clean water.

RECENT REVIEW OF THE QUECHERS SAMPLE PREPARATION METHOD FOR FOOD AND ENVIRONMENTAL SAMPLE ANALYSIS

Creating reliable, environmentally responsible, and effective processes that ensure the traceability, safety, and caliber of their results is one of the main challenges facing researchers doing multi-residue analysis. The QuEChERS which stands for Quick, Easy, Cheap, Effective, Rugged, and Safe method has shown itself to be highly adaptable, yielding positive outcomes with a range of analytes. This method allows for versatility in the choice of solvents, salts, and buffers for salting-out partitioning, as well as the use of various sorbents throughout the cleanup process. QuEChERS is a more environmentally friendly sample preparation technique that fits perfectly with analytical chemistry's rising emphasis on sustainability. This review paper's goal is to illustrate the primary applications of the QuEChERS sample preparation method, with a focus on food and environmental investigations. It also covers important improvements in the history of sample preparation methods and offers insights into the classes of substances that have been effectively evaluated with this methodology.

Facile and versatile PDMS-glass capillary double emulsion formation device coupled with rapid purification toward microfluidic giant liposome generation

The exceptional ability of liposomes to mimic a cellular lipid membrane makes them invaluable tools in biomembrane studies and bottom-up synthetic biology. Microfluidics provides a promising toolkit for creating giant liposomes in a controlled manner. Nevertheless, challenges associated with the microfluidic formation of double emulsions, as precursors to giant liposomes, limit the full exploration of this potential. In this study, we propose a PDMS-glass capillary hybrid device as a facile and versatile tool for the formation of double emulsions which not only eliminates the need for selective surface treatment, a well-known problem with PDMS formation chips, but also provides fabrication simplicity and reusability compared to the glass-capillary formation chips. These advantages make the presented device a versatile tool for forming double emulsions with varying sizes (spanning two orders of magnitude in diameter), shell thickness, number of compartments, and choice of solvents. We achieved robust thin shell double emulsion formation by operating the hybrid chip in double dripping mode without performing hydrophilic/phobic treatment a priori. In addition, as an alternative to the conventional, time-consuming density-based separation method, a tandem separation chip is developed to deliver double emulsions free of any oil droplet contamination in a continuous and rapid manner without any need for operator handling. The applicability of the device was demonstrated by forming giant liposomes using the solvent extraction method. This easy-to-replicate, flexible, and reliable microfluidic platform for the formation and separation of double emulsion templates paves the way for the high-throughput microfluidic generation of giant liposomes and synthetic cells, opening exciting avenues for biomimetic research.The presented giant liposome assembly line features a novel treatment-free hybrid chip for double emulsion formation coupled with a high throughput separation chip for sample purification.

Shielding Fluoride Ion Basicity through Diurea Coordination for Nonaqueous Fluoride Shuttle Batteries

AbstractThe strong basicity of fluoride ions leads to detrimental nucleophilic attack on organic components in the electrolytes, such as β‐hydrogen elimination reactions with organic cations and solvents, converting “naked” F− into corrosive and unstable bifluoride (HF2−) ions. These reactions significantly constrain the choice of suitable solvents and salts to develop electro(chemical) stable fluoride ion electrolytes. In this work, we replaced the triple water ligands typically present in industrial organic fluoride salts with dual 1,3‐diphenylurea (DPU) coordination via hydrogen bonding interaction. This modification successfully suppressed the Lewis basicity of fluoride ions, providing long‐term chemical stability (over 1000 hours) across a wide range of aprotic solvents, a broadened electrochemical stability window (−2.5–0.9 V vs. Ag+/Ag) and high ionic conductivity (1.7 mS cm−1) at room temperature. Additionally, the weaker hydrogen bonding in F−‐DPU coordination, compared to the conventional boron‐based anion acceptor (AA) strategy that relies on intensive Lewis acid‐base interactions, facilitates faster (de)fluorination kinetics at the electrode. The proposed room temperature fluoride ion batteries sustain improved electrochemical performance by pairing with the Pb‐PbF2 anode and BiF3 or Ag cathode.

Shielding Fluoride Ion Basicity through Diurea Coordination for Nonaqueous Fluoride Shuttle Batteries.

The strong basicity of fluoride ions leads to detrimental nucleophilic attack on organic components in the electrolytes, such as β-hydrogen elimination reactions with organic cations and solvents, converting "naked" F- into corrosive and unstable bifluoride (HF2 -) ions. These reactions significantly constrain the choice of suitable solvents and salts to develop electro(chemical) stable fluoride ion electrolytes. In this work, we replaced the triple water ligands typically present in industrial organic fluoride salts with dual 1,3-diphenylurea (DPU) coordination via hydrogen bonding interaction. This modification successfully suppressed the Lewis basicity of fluoride ions, providing long-term chemical stability (over 1000 hours) across a wide range of aprotic solvents, a broadened electrochemical stability window (-2.5-0.9 V vs. Ag+/Ag) and high ionic conductivity (1.7 mS cm-1) at room temperature. Additionally, the weaker hydrogen bonding in F--DPU coordination, compared to the conventional boron-based anion acceptor (AA) strategy that relies on intensive Lewis acid-base interactions, facilitates faster (de)fluorination kinetics at the electrode. The proposed room temperature fluoride ion batteries sustain improved electrochemical performance by pairing with the Pb-PbF2 anode and BiF3 or Ag cathode.

Complexation of Actinyl Ions with DHOA and TBP in an Ionic Liquid and a Molecular Solvent: How Similar or Different Are They?

Complexation thermodynamics of uranyl ions with well-known reprocessing ligands like tributyl phosphate (TBP) and dihexyl octanamide (DHOA) was studied in an ionic liquid (IL) versus a molecular solvent. Whereas 1-butyl-3-methylimidazolium bis(trifluoromethyl sulfonyl)imide (Bumim·Tf2N) was used as an IL due to its favorable viscosity, acetonitrile was the choice of molecular solvent due to its poor coordinating nature. Optical spectroscopy studies revealed that UO22+ ions formed species of the types ML1 and ML2 with both TBP and DHOA, in a stepwise manner. The formation constants (log β) of UO22+ with DHOA in the IL were determined as 3.58 ± 0.03 and 6.54 ± 0.10, while those with TBP were obtained as 3.42 ± 0.05 and 6.38 ± 0.08, respectively. In the case of acetonitrile, on the other hand, these β values were significantly lower than those observed in the IL medium, which was supported by the DFT calculations. Calorimetric titrations of the UO22+ ions with DHOA and TBP confirmed that the complex formation reactions were thermodynamically more favored in the ionic liquid medium than the molecular solvent. The nature of binding through FTIR investigations and DFT calculations suggested that the complexes formed in the IL medium were cationic in nature of the types [UO2(H2O)3(TBP)2]2+ and [UO2(H2O)3(DHOA)2]2+, but neutral complexes were formed in the molecular solvent of the types [UO2(NO3)2(TBP)2] and [UO2(NO3)2(DHOA)2].

Effect of Carbonate Solvent Additives in Electrolyte on the Self-Discharge Phenomenon in Organic Electrical Double Layer Capacitors

As a result of industrialization, technological progress, and the growing global population, energy consumption worldwide is skyrocketing. Researchers are thriving to seek high power density storage device to meet these escalating energy demands. Electrical Double Layer Capacitors (EDLCs) also known as a supercapacitor, are energy storage devices that store energy by Coulombic attraction between ions, polarized solvent on the surface of the activated carbon electrodes to form an electric double layer without involving chemical reactions. EDLCs display some remarkable characteristics such as high-power density, ultrafast charge/discharge rates, and long cycle life, surpassing conventional lithium-ion batteries. These features make EDLCs ideal for a wide range of applications, including portable devices, energy backup systems, and electric vehicles.However, the self-discharge effect in EDLCs is a deadly drawback that decrease the shelf life of EDLCs and impeding its practical applications. This phenomenon refers to the spontaneous voltage decay between the electrodes when the capacitor is under open-circuit potential after being charged, leading to a reduction in the stored charge without any external connection. This voltage declination is a complex process therefore, various mechanisms have been proposed to elucidate this phenomenon. There are primarily four mechanisms leading to the self-discharge. First, the internal short-circuit caused by imperfect seal of EDLCs leading to ohmic leakage current. Second, the uneven distribution of pore sizes in activated carbon electrodes leads to a higher resistance for ions to penetrate deeper into the material, resulting in ion accumulation on the surface during short charging times. This accumulation causes an uneven distribution of electron energy in the electrode material. After disconnecting, electrons rearrange to achieve overall energy consistency, while ions gradually redistribute and move into the smaller micropores within the activated carbon electrode. This phenomenon is referred to as charge redistribution effect. Third, Faradic current in EDLCs occurs due to redox reactions, stemming from the decomposition of the electrolyte or chemical reactions involving impurities within the electrolyte. Lastly, during the charging process, ions accumulate at the electrode surface, creating a concentration gradient between the electrodes and the electrolyte. As a result, ions gradually diffuse back into the bulk electrolyte until reaching equilibrium. Addressing self-discharge is paramount in ongoing research efforts.Electrolyte solutions are critical components in EDLCs, providing a medium for ion transport between the electrodes. The electrolyte solution is typically composed of a supporting electrolyte dissolved in a solvent, and the choice of solvent can significantly impact the performance of the device. This study delves into the impact of electrolyte solvent additives in the electrical double layer of EDLCs, leading to varied self-discharge performances. In this report, five commonly-used organic carbonate solvents in EDLCs, were selected to investigate their effects on the self-discharge phenomenon. Cyclic carbonate solvents, such as EC and PC, are known to possess high dielectric constants, high viscosities and high flash points. In contrast, linear carbonates e.g., DEC, DMC, EMC have low viscosities, low dielectric constants and low flash point. By incorporating carbonate solvents into the 1M TEABF4/PC (Tetraethylammonium tetrafluoroborate/propylene carbonate) commercial electrolyte, the performance of five supercapacitors , minimal deviation in electrochemical analyses such as CV and GCD was observed. However, significant differences emerged in EIS, elucidating the varying degrees of self-discharge phenomena. These differences in self-discharge mechanisms across the five EDLCs stemmed from the distinct dielectric constants and molecule sizes of the five solvent additives (i) Low dielectric constant and large molecule size, as seen in DEC (239.4h) and EMC (165.1h), contributed to increased interfacial impedance which effectively prolonging self-discharge compared to commercial one (145.7h). Conversely, the DMC with smaller interfacial resistance initially exhibited lower voltage decline due to reduced charge redistribution effects. However, its rapid ion diffusion process from carbon pores to electrolyte resulted in the fastest self-discharge of DMC (124.7h). (ii) High dielectric EC competes for solvation coordination, reducing interfacial resistance and enhancing intermolecular interaction. This, in turn, leads to the formation of a denser electric double layer (EDL) with EC, therefore decelerating the self-discharge process (205.9h) in EDLCs. In summary, the study emphasizes the significance of solvent additive selection and demonstrates a simple, safe, and cost-effective method to prolonging the self-discharge duration of DEC to more than 1.5 times that of the commercial one, significantly inhibiting the critical self-discharge issue in supercapacitors. Figure 1

Binary Solvent Induced Stable Interphase Layer for Ultra-Long Life Sodium Metal Batteries

Lithium-ion batteries (LIBs) face concerns about production capacity and critical material shortages in the pursuit of reliable energy storage for intermittent renewable sources.1,2 As an alternative, sodium-ion batteries (SIBs) offer a comparable storage mechanism using abundant and cost-effective sodium as the energy host.3 With sodium's abundance surpassing lithium by ≈1000 times, SIBs present a compelling solution for future energy storage needs.1 Sodium metal boasts a high theoretical capacity of 1166 and 1131 mA h cm−3, coupled with a low redox potential of −2.71 V versus standard hydrogen electrode (SHE).4 These attributes pave the way for exploring the potential applications of metal anode-based batteries in energy density-intensive electric vehicles and more efficient stationary storage systems for renewable energy sources.5 However, addressing the challenges associated with parasitic reactions involving alkali metal anodes is essential. These reactions can lead to the formation of unstable solid electrolyte interphase (SEI) and dendrites, which not only diminish battery longevity but also pose safety hazards.6 The past decade has seen extensive research efforts aimed at achieving stable cycling of sodium metal batteries (SMBs), addressing challenges like parasitic reactions and dendrite formation.1,7,8 Various strategies, including the use of additives,4 artificial SEI formation,9 and directed sodium deposition,10 have been explored to enhance SMB lifespan. Notably, modifying the electrolyte composition, particularly the choice of solvent, stands out as a straightforward yet practical approach.8 Solvent selection significantly influences the physical and chemical properties of the electrolyte, impacting salt solvation and SEI layer formation. Recent studies have shown promising results with ether-based solvents such as diglyme (Dig) and tetrahydrofuran (THF), promoting stable SEI layer formation due to the presence of aggregates (AGGs) solvation structure.7,11 However, the sustainability of high salt concentrations remains a concern due to cost implications and limited ionic conductivity.8,12 Here, solvent engineering offers a solution by adjusting the mixture ratio of solvents to create localized high-concentration electrolytes, enhancing SMB stability.8,13 Furthermore, environmentally friendly solvents like 2-methyl tetrahydrofuran (MTHF) present a promising co-solvent option, offering weaker Na⁺ ion solvation characteristics and lower viscosity, potentially improving SMB performance, especially at lower salt concentrations.14,15 Hence, introducing MTHF as a co-solvent to Dig holds the potential to enhance SMB rate capability and stability, even at reduced salt concentrations.In this study, a stable sodium metal battery (SMB) is achieved by tuning the electrolyte solvation structure through the addition of co-solvent 2-methyl tetrahydrofuran (MTHF) to diglyme (Dig). The introduction of cyclic ether-based MTHF results in increased anion incorporation in the solvation structure, even at lower salt concentrations. Specifically, the anion stabilization capabilities of the environmentally sustainable MTHF co-solvent lead to a contact-ion pair-based solvation structure. Time-of-flight mass spectroscopy analysis reveals that a shift toward an anion-dominated solvation structure promotes the formation of a thin and uniform SEI layer. Consequently, employing a NaPF6-based electrolyte with a Dig:MTHF ratio of 50% (v/v) binary solvent yields an average Coulombic efficiency of 99.72% for 300 cycles in Cu||Na cell cycling. Remarkably, at a C/2 cycling rate, Na||Na symmetric cell cycling demonstrates ultra-long-term stability exceeding 7000 h, and full cells with Na0.44MnO2 as a cathode retain 80% of their capacity after 500 cycles. This study systematically examines solvation structure, SEI layer composition, and electrochemical cycling, emphasizing the significance of MTHF-based binary solvent mixtures for high-performance SMBs. References G. G. Eshetu et al., Adv. Energy Mater., 10, 2000093 (2020). Energy Storage Assoc. https://energystorage.org/why-energy-storage/benefits/.C. Delmas, Adv. Energy Mater., 8, 1703137 (2018).B. Sun et al., Adv. Mater., 32, 1903891 (2020).U.-H. Kim et al., ACS Energy Lett., 7, 3880–3888 (2022).B. Lee, E. Paek, D. Mitlin, and S. W. Lee, Chem. Rev., 119, 5416–5460 (2019).L. Zhu et al., Green Energy Environ., 8, 1279–1307 (2023).Z. Tian et al., Adv. Sci., 9, 2201207 (2022).Z. W. Seh, J. Sun, Y. Sun, and Y. Cui, ACS Cent. Sci., 1, 449–455 (2015).Z. Sun et al., Small, 18, 2107199 (2022).R. Cao et al., Nano Energy, 30, 825–830 (2016).Y. Li et al., ACS Energy Lett., 5, 1156–1158 (2020).J. Zheng et al., ACS Energy Lett., 3, 315–321 (2018).C.-C. Su, M. He, R. Amine, Z. Chen, and K. Amine, Angew. Chem. Int. Ed., 57, 12033–12036 (2018).D. Guo, J. Wang, T. Lai, G. Henkelman, and A. Manthiram, Adv. Mater., 35, 2300841 (2023). Figure 1

Solvent-Confined Van Der Waals Gap Engineering to Improve Energy Storage in a 2D Layered Supercapacitor

Despite the rapidly growing demand for high-performance and eco-friendly supercapacitors in the pursuit of sustainable energy storage, achieving both high volumetric energy density and ultrafast charging remains a significant challenge. Two-dimensional layered materials (2DLM) have emerged as promising electrode materials due to their ability to form highly networked nanochannels. Understanding the transport behavior of ions within these nanochannels is crucial for efficient energy storage. Recent advancements have shown promise in creating nanochannels that enhance ion transport and storage. However, controlling the properties of nanochannels has been challenging due to their nanoscale size and limited choice of solvents primarily water.Here, we propose a manufacturing method of 2DLM films that confines various solvents within the van der Waals gap, allowing for adjustable thickness from nano to micro dimensions. The confined solvents serve as nanofluidic channels, improving ion transport and achieving high-density energy storage. Our ethanol-confined films demonstrate a gravimetric capacitance of 302 F g-1 and a volumetric capacitance of 1033 F cm-3, measured at a scan rate of 100 mV s-1, which is twice as high as water-confined films. By selectively controlling the nanochannels, we can regulate the channel distance and density of the film, effectively enhancing the electrode surface potential and enabling ultrafast ion transport. This demonstration offers valuable insights into the design of 2DLM films for energy storage and conversion applications.

Influence of Solvents on Catalyst Layer Performance in Proton Exchange Membrane Water Electrolysis and Fuel Cells

Proton exchange membrane (PEM) water electrolysis (WE) and fuel cells (FCs) stand out as promising technologies for hydrogen generation and utilization, leveraging renewable and sustainable energy sources. A pivotal element in both PEMFC and PEMWE is the membrane-electrode assembly (MEA), comprising catalyst layers (CLs) and a membrane. These CLs facilitate electrochemical reactions at the anode and cathode, crucial for both oxygen reduction reaction (ORR) and hydrogen evolution reaction (HER) in PEMWE and PEMFC. The catalyst ink for CLs consists of electrocatalyst, ionomer dispersion, and additional solvents. Among these components, the choice of solvent significantly influences PEMFC and PEMWE performance, shaping the catalyst ink's properties. In this investigation, we formulated ionomer dispersions for CLs to enhance performance in PEMWE and PEMFC. We scrutinized the effects of solvents in terms of solvation energy, thermogravimetric analysis (TGA), particle size distribution (PSD), and electrochemical assessment. Acknowledgments This research was supported in part by the New and Renewable Energy of the Korea Institute of Energy Technology Evaluation and Planning (KETEP) granted financial resource from the Ministry of Trade, Industry & Energy, Republic of Korea (No. 20213030040520) and by 2021 Green Convergence Professional Manpower Training Program of the Korea Environmental Industry and Technology Institute funded by the Ministry of Environment.