Acid-base Interactions Research Articles

Synergistic enhancement of N, S co-modified biochar for removal of tetracycline hydrochloride from aqueous solution: Tunable micro-mesoporosity and chemisorption sites

The misuse of tetracycline hydrochloride (TCH) antibiotics has caused irreversible hazards to ecosystem. In this study, a series of porous biochar with tunable micro-mesoporosity and chemisorption sites are designed by cleverly exploiting the pyrolysis properties of active agents in various temperature regions. Benefiting from the existence of more pore structures matching the adsorbate while exposing more chemisorption sites, the maximum adsorption capacity (Qm) of NSC-1.0 for TCH is up to 1480.1 mg g−1 at 303 K. A combination of model fitting, post characterization and density functional theory (DFT) calculations confirms that the adsorption process involves the pore filling, the formation of non-covalent bonds (weak hydrogen bond, π-π stacking, electrostatic interaction) and ligand covalent bonding (Lewis acid-base interaction). The Qm is positively correlated with the volume of pore size greater than 1 nm (R2 = 0.9879), indicating that the pore filling effect is a decisive factor for adsorption performance. Post-characterization directly demonstrates that weak hydrogen bonding and π-π stacking are pivotal physical interactions for adsorption. DFT calculations show that partial N, S species and oxygen-containing functional groups can significantly reduce the adsorption energy of intrinsic graphene, especially the chemisorption sites of pyrrolic N (N5) and thiophene S (S5) containing lone-pair electrons. Furthermore, the competitiveness of NSC-1.0 is revealed in practical evaluation, including cation strength, regenerability, actual water source and fixed-bed column. This study not only contributes new insights to synergistically enhance the removal of macromolecular antibiotics by coupling matchable pore sizes and chemisorption sites, but also develops theoretical support for the fabrication of such efficient adsorbents.

Composite polymer electrolyte facilitated by enhanced amorphousity and Li+ conduction using LaFeO3-embedded PVDF-HFP for solid-state lithium metal battery

Composite polymer electrolytes (CPEs) are a promising alternative to flammable conventional liquid electrolytes for high-safety lithium-ion batteries. Establishing low-cost filler that enhances the amorphous nature of polymer in the CPEs and exhibits efficient Lewis acid-base interaction between fillers and anions of lithium salt, leading to improved dissociation of salts for enhanced conduction, is indispensable. In this work, for the first time, we construct a solid composite polymer electrolyte of poly(vinylidene fluoride hexafluoropropylene) embedded LaFeO3 (LFO) particles prepared by solution casting and electrospinning methods and study their performances. The 5 wt% LFO filler embedded CPE made by means of solution casting and electrospinning methods exhibited the highest ionic conductivity of 5.9 × 10-4 and 1.49 × 10-3 S cm−1 at room temperature and electrochemical stability window up to 4.6 and 4.45 V, respectively. Further, as-assembled solid-state lithium-ion batteries using electrospun CPE showed an initial discharge capacity of 166 mAh/g at 0.1C-rate and solution-casted CPE showed excellent cycling stability with 98.6 % capacity retention at 0.3C-rate even at 50th cycle. Such excellent performance originated from the introduction of the LFO particles as filler into the polymer matrix to enhance the ionic conductivity, mechanical strength and lithium metal compatibility of the resulting CPEs.

Fabrication of Nitrogen Based Magnetic Conjugated Microporous Polymer for Efficient Extraction of Neonicotinoids in Water Samples.

Facile and sensitive methods for detecting neonicotinoids (NEOs) in aquatic environments are crucial because they are found in extremely low concentrations in complex matrices. Herein, nitrogen-based magnetic conjugated microporous polymers (Fe3O4@N-CMP) with quaternary ammonium groups were synthesized for efficient magnetic solid-phase extraction (MSPE) of NEOs from tap water, rainwater, and lake water. Fe3O4@N-CMP possessed a suitable specific surface area, extended π-conjugated system, and numerous cationic groups. These properties endow Fe3O4@N-CMP with superior extraction efficiency toward NEOs. The excellent adsorption capacity of Fe3O4@N-CMP toward NEOs was attributed to its π-π stacking, Lewis acid-base, and electrostatic interactions. The proposed MSPE-HPLC-DAD approach based on Fe3O4@N-CMP exhibited a wide linear range (0.1-200 µg/L), low detection limits (0.3-0.5 µg/L), satisfactory precision, and acceptable reproducibility under optimal conditions. In addition, the established method was effectively utilized for the analysis of NEOs in tap water, rainwater, and lake water. Excellent recoveries of NEOs at three spiked levels were in the range of 70.4 to 122.7%, with RSDs less than 10%. This study provides a reliable pretreatment method for monitoring NEOs in environmental water samples.

Anion-Responsive Colorimetric and Fluorometric Red-Shift in Triarylborane Derivatives: Dual Role of Phenazaborine as Lewis Acid and Electron Donor.

Photophysical modulation of triarylboranes (TABs) through Lewis acid-base interactions is a fundamental approach for sensing anions. Yet, design principles for anion-responsive TABs displaying significant red-shift in absorption and photoluminescence (PL) have remained elusive. Herein, a new strategy for modulating the photophysical properties of TABs in a red-shift mode has been presented, by using a nitrogen-bridged triarylborane (1,4-phenazaborine: PAzB) with a contradictory dual role as a Lewis acid and an electron donor. Following the strategy, PAzB derivatives connected with an electron-deficient azaaromatic have been developed, and these compounds display a distinct red-shift in their absorption and PL in response to an anion. Spectroscopic analyses and quantum chemical calculations have revealed the formation of a tetracoordinate borate upon the addition of fluoride, narrowing the HOMO-LUMO gap and enhancing the charge-transfer character in the excited state. This approach has also been demonstrated in modulating the photophysical properties of solid-state films.

Separation of ethylene glycol from propylene glycol via selective adsorption with basic anion-exchange resin

Ethylene glycol (EG) is a common impurity in bio-derived 1,2-propylene glycol (PG). EG was isolated from PG via selective adsorption on basic ion-exchange resin. A small amount of moisture improved the porosity of resin, thereby reinforcing the intraparticle diffusion and adsorption performance. The adsorption equilibrium could be reached within 1 min, indicating that EG can be instantly removed. The real adsorption capacity for PG was much lower than that for EG, and the selectivity was up to 5.5 at 60 °C due to the susceptibility of PG adsorption to temperature. The PG content was increased from 90 to 95.7 wt% in a continuous-flow process with low bed pressure drop. The EG adsorption process agreed with the Langmuir isotherm model, and the apparent EG adsorption capacity reached 250.6 mg/g at 60 °C, while real PG adsorption capacity was negligible. The different interactions between diols and OH− ions were proven by UV and surface-tension measurements, and the stronger acidity of hydroxyl group in EG contributed to its stronger acid-base interaction with basic materials. The resin adsorbent could be reused and completely regenerated without leaching via elution with 20 wt% NaOH. Based on the acidity of EG, this work presents an unprecedented cost-effective strategy to separate diols.

Synergistic effect of Ti3C2Tx MXene/PAN nanofiber and LLZTO particles on high-performance PEO-based solid electrolyte for lithium metal battery

Solid polymer electrolytes (SPEs) have been considered the most promising separators for all-solid-state lithium metal batteries (ASSLMBs) due to their ease of processing and low cost. However, the practical applications of SPEs in ASSLMBs are limited by their low ionic conductivities and mechanical strength. Herein, we developed a three-dimensional (3D) interconnected MXene (Ti3C2Tx) network and Li6.4La3Zr1.4Ta0.6O12 (LLZTO) particles synergistically reinforced polyethylene oxide (PEO)-based SPE, where the association of Li+ with ether-oxygen in PEO could be significantly weakened through the Lewis acid-base interactions between the electron-absorbing group (Ti–F, −O–) of Ti3C2Tx and Li+. Besides, the TFSI− in lithium salts could be immobilized by hydrogen bonds from the Ti–OH of Ti3C2Tx. The 3D interconnected Ti3C2Tx network not only alleviated the agglomeration of inorganic fillers (LLZTO), but also improved the mechanical strength of composite solid electrolyte (CSE). Consequently, the assembled Li||CSE||Li symmetric battery showed excellent cycling stability at 35 ℃ (stable cycling over 3000 h at 0.1 mA cm−2, 0.1 mAh cm−2) and −2 ℃ (stable cycling over 2500 h at 0.05 mA cm−2, 0.05 mAh cm−2). Impressively, the LiFePO4||CSE||Li battery showed a high discharge capacity of 145.3 mAh/g at 0.3 C after 300 cycles at 35 ℃. This rational structural design provided a new strategy for the preparation of high-performance solid-state electrolytes for lithium metal batteries.

Influence of activated protons and acid–base pairs on proton conduction in imino-functionalized MOF-based hybrid membranes

The rich activated protons and effective proton-conducting paths are of importance to improve conductivities of conductors. Herein, a series of Brönsted acids as proton carrier and proton transfer sites is introduced into the highly stable MOF, contributing to create plentiful hydrogen bonds within frameworks. Consequently, the trifluoromethanesulfonic acid-embedded JUC-1000 ([Cu24(BDPO)12(H2O)12]) displays the relatively highest conductivity of 7.04 × 10−4 S cm−1 under ∼98% RH and 328 K, ∼16 times that of JUC-1000 (4.47 × 10−5 S cm−1). When TMSA@JUC-1000 (TMSA = CF3SO3H) blended with chitosan (CS), the proton conductivity of TMSA@JUC-1000/CS-15 is the highest at ∼76% RH and 328 K (1.01×10−2 S cm−1), which is six times higher than that of JUC-1000/CS (1.85×10−3 S cm−1). The CS contains abundant –NH2 and –OH groups as proton jumping sites, which would activate the –NH– or –OH bonds of JUC-1000 and the acidic groups in Brönsted acids. These would result in an increased content of activated protons and effective formation of H-bonding nets by acid-base interactions. The findings provide valuable insights into the potential application of MOFs materials in energy devices.

Introduction of an electrospun nanofibrous membrane incorporated by metal-organic framework-199 (MOF-199) with Lewis acid property for efficient extraction of sulfonamides in on-chip electromembrane extraction

In this study, a new supporting polymeric membrane having Lewis acid nature was introduced for immobilizing organic solvent in on-chip electromembrane extraction (on-chip EME). For this aim, a polymeric nanofibrous membrane incorporated by a copper based metal-organic framework (MOF-199), with coordinatively unsaturated metal sites and Lewis acid property, was prepared by electrospinning a mixture of polycaprolactone (PCL) and MOF-199. Based on the field emission scanning electron microscopy images, the obtained polymeric membrane consisted of intertwined nanofibers having empty space between the fibers which could provide a suitable place for immobilizing the organic solvent. To demonstrate remarkable extractability of the proposed membrane (PCL/MOF-199 nanofibers) via executing Lewis acid-base interactions, three sulfonamide drugs was selected as anionic polar analytes with Lewis base feature. The parameters affecting the extraction efficiency of the method were optimized through the experimental design method using the orthogonal and rotatable central composite design (CCD). Under optimum conditions, the extraction recoveries ranging from 35.5 to 71.2 %, the relative standard deviations (RSD%) less than 6.45 %, and the detection limits in the range of 0.2–0.5 μg L−1 were achieved. The comparison of the extraction efficiency of the on-chip EME method using the electrospun PCL/MOF-199 nanofibers and PCL nanofibers membranes indicated that the proposed membrane was more efficient for extraction of sulfonamides because of the significant Lewis acid-base interactions of sulfonamides with copper uncoordinated open sites in MOF-199. Finally, the performance of the proposed method for extraction and determination of sulfonamides in three real samples was assayed.

Theoretical Validation of Reversible Acidochromism of a Cinnamaldehyde based Scaffold with Experimental Investigations

Present study explores the reversible acidochromism displayed by cinnamaldehyde derivative-based scaffold (P1), which is highly sensitive to variations in acidity and basicity. Upon exposing to an acidic environment, the solution containing P1 undergoes a vivid colour shift from yellow to a vibrant pink-fuchsia colour due to the conversion of imine within P1 into its quinonoid form. The color change can be completely reversed by adding a basic material, demonstrating the reversible acidochromic behavior of the P1 system. Moreover, the practical application of this acidochromic property is demonstrated through the development of a test kit utilizing paper strips. This kit effectively harnesses the acidochromic nature of P1 to detect even minute quantities of acidic or basic substances in solutions. The underlying mechanisms of the acid-base detection and corresponding colorimetric shifts in response to the acid-base interactions have meticulously been explored using density functional theoretical investigations.

Nitrogen-rich, potato peel-derived hydrochar as an effective dye adsorbent

This study explores the potential of hydrochar derived from potato peels as a cost-effective option for efficient adsorption. Potato peel hydrochar (PPH) was produced via hydrothermal carbonization (HTC) with KOH activation at 200 °C for 2 h. The resulting hydrochar was then divided into three portions, two of which underwent mixing with urea followed by pyrolysis under N2 gas at 600 °C for 2 and 3 h, respectively, resulting in the formation of N-doped pyrochars (N-PPH.2 hrs and N-PPH.3 hrs). Characterization using Brunauer-Emmett-Teller (BET), Scanning Electron Microscope (SEM), Energy-Dispersive X-ray Spectroscopy (EDS), X-ray Diffraction (XRD), and Fourier Transform Infrared Spectroscopy (FTIR) revealed distinctive properties. The results showed that nitrogen atoms were effectively incorporated into the pyrochar, increasing significantly from 3.7 to 8.3% and then to 45.6% as new nitrogen compounds. This modification impacted the acidity and basicity of the chemical surfaces of the pyrochar. The N-doped pyrochar, with a particle sizve of N-doped compounds at 296.11 nm, demonstrated the most efficient adsorption of Congo red (CR). This efficiency was achieved through various mechanisms, including pore filling, Lewis acid-base interaction, hydrogen bonding, and π–π interaction. The presence of highly available functional groups, primarily pyridinic-N, pyrrolic-N, and graphitic-N, further enhanced the adsorption capacity. The highest adsorption capacities were observed at 310 mg g−1 for N-PPH-2Hr and 400 mg g−1 for N-PPH-3Hr, respectively. Increased temperature and CR concentration correlated positively with enhanced adsorption, following Freundlich isotherm and pseudo second-order kinetics. Further, the results indicate that the adsorption of Congo red by the prepared chars is endothermic, increases disorder, and is a spontaneous process. This study highlights the cost-effectiveness of agro-industrial waste-derived chars for Congo red removal, highlighting economic and environmental benefits.

Sonocatalytic Activity of Porous Carbonaceous Materials for the Selective Oxidation of 4-Hydroxy-3,5-dimethoxybenzyl Alcohol.

Selective oxidation, which is crucial in diverse chemical industries, transforms harmful chemicals into valuable compounds. Heterogeneous sonocatalysis, an emerging sustainable approach, urges in-depth exploration. In this work, we investigated N-doped or non-doped carbonaceous materials as alternatives to scarce, economically sensitive metal-based catalysts. Having synthesized diverse carbons using a hard-template technique, we subjected them to sonication at frequencies of 22, 100, 500, and 800 kHz with a 50% amplitude. Sonochemical reaction catalytic tests considerably increased the catalytic activity of C-meso (non-doped mesoporous carbon material). The scavenger test showed a radical formation when this catalyst was used. N-doped carbons did not show adequate and consistent sonoactivity for the selective oxidation of 4-Hydroxy-3,5 dimethoxybenzyl alcohol in comparison with control conditions without sonication, which might be associated with an acid-base interaction between the catalysts and the substrate and sonoactivity prohibition by piridinic nitrogen in N-doped catalysts.

Mutual role of dodecylbenzene sulfonic acid on enhanced oil recovery and asphaltene inhibition in low salinity medium: Experimental and XDLVO study

Understanding the molecular interactions during oil recovery processes can shed light on screening new chemicals for future operations. Of particular interest are chemicals capable of providing the mutual role of asphaltene inhibition and interfacial tension reduction at liquid–liquid and rock-liquid interfaces. This study delves into the interfacial interactions between low-salinity brines, model oils containing dodecylbenzene sulfonic acid, and dolomite rock surfaces. In the experimental part, the asphaltene precipitation inhibition efficacy of dodecylbenzene sulfonic acid was evaluated through filtration and precipitation test, and its oil recovery performance was examined from interfacial tension reduction and wettability alteration viewpoints. The theoretical part was then followed by the implementation of the surface energy concept based on the XDLVO theory, where acid-base and Lifshitz-van der Waals interaction energies, as well as the work of cohesion/adhesion between interacting bodies in asphaltene and oil recovery systems, were considered. The results obtained from this study revealed that dodecylbenzene sulfonic acid, owing to its acidic nature and the long alkyl chain in its structure, could simultaneously perform the role of asphaltene inhibitor and oil recovery agents. In particular, asphaltene particles showed less tendency to aggregate and form macrostructures in the presence of low-salinity brines formulated with magnesium chloride. The total interaction energy between asphaltene particles was almost halved by the addition of dodecylbenzene sulfonic acid. The low interfacial tension of 0.16 mN/m between model oil containing 1 wt% of DBSA and low-salinity brine containing 5000 mg/L magnesium chloride and the wettability alteration of the dolomite sample toward water-wetness were also confirmed by theoretical calculations using the concept of work of adhesion.

Adsorption of tetracycline by nitrogen-enriched biochar prepared at different pyrolysis temperatures: Considering the crucial role of nitrogen configuration

Nitrogen atom doping is widely employed to prepare efficient adsorbents to handle target pollutants thanks to its similarity in radius to carbon atoms and excellent functionality. In this study, three types of nitrogen-enriched biochars (NBCs) were prepared to use the corn straw as the raw material and melamine as the nitrogen source by pyrolyzing at 700, 800, and 900 °C (named 700NBC, 800NBC and 900NBC), which were used to remove tetracycline (TC) from water. Results showed that the 900NBC exhibited the highest specific surface area (324.29 m2/g) as well as the maximum adsorption capacity (194.42 mg/g) for TC, compared to 800NBC (176.44 mg/g) and 700NBC (163.32 mg/g). What’s more, the adsorption kinetics and adsorption isotherms were well-fitted by the pseudo-second-order and Langmuir models, indicating that for the adsorption of TC by NBCs, monolayer adsorption and chemisorption were dominant. Specifically, the excellent adsorption performance of NBCs for TC was mostly attributed to the pore filling, hydrogen bonding, π-π interactions, Lewis acid-base interactions, and electrostatic interactions. Importantly, the graphitic N serves as the primary TC adsorption site, followed by pyridinic N. This study would provide new insight into the impact of nitrogen configuration on the adsorption mechanism of NBCs for TC.

Cationic cellulose nanofiber solid electrolytes: A pathway to high lithium-ion migration and polysulfide adsorption for lithium-sulfur batteries

Polyethylene oxide (PEO) solid electrolytes, acknowledged for their safety advantages over liquid counterparts, confront inherent challenges, including low ionic conductivity, restricted lithium ion migration, and mechanical fragility, notably pronounced in lithium‑sulfur batteries due to the polysulfide shuttling phenomenon. To address these limitations, we integrate a quaternary ammonium cation-modified cellulose (QACC) nanofiber, electrospun with cellulose acetate (CA) from recycled cigarette filters, into the PEO electrolyte matrix. The nitrogen atom within the quaternary ammonium group exhibits a pronounced affinity for polysulfide compounds, effectively curtailing polysulfide migration. Concurrently, Lewis acid-base interactions between quaternary ammonium groups and lithium salt anions facilitate the release of additional Li+, achieving a lithium-ion transference number 1.5 times higher than its pure PEO counterpart. Furthermore, the introduction of a larger trifluoromethanesulfonimide (TFSI) group on the QACC macromolecule (TFSI-QACC) disrupts the ordered arrangement of PEO macromolecules, resulting in a noteworthy enhancement in ionic conductivity, reaching 2.07 × 10−4 S cm−1 at 60 °C, thus addressing the challenge of low PEO electrolyte conductivity. Moreover, the nanofiber enhances the mechanical strength of the PEO electrolyte from 0.49 to 7.50 MPa, mitigating safety concerns related to lithium dendrites puncturing the electrolyte. Consequently, the composite PEO demonstrates exemplary performance in lithium symmetrical batteries, enduring 500 h of continuous operation and completing 100 cycles at both room and elevated temperatures. This integrated approach, transitioning from waste to wealth, adeptly addresses a spectrum of challenges in the efficiency of solid-state electrolytes, holding considerable promise for advancing lithium‑sulfur battery technology.

Synergy of machine learning and density functional theory calculations for predicting experimental Lewis base affinity and Lewis polybase binding atoms.

Investigation of Lewis acid-base interactions has been conducted by ab initio calculations and machine learning (ML) models. This study aims to resolve two critical tasks that have not been quantitatively investigated. First, ML models developed from density functional theory (DFT) calculations predict experimental BF3 affinity with Pearson correlation coefficients around 0.9 and mean absolute errors around 10 kJ mol-1. The ML models are trained by DFT-calculated BF3 affinity of more than 3000 adducts, with input features readily obtained by rdkit. Second, the ML models have the capability of predicting the relative strength of Lewis base binding atoms in Lewis polybases, which is either an extremely challenging task to conduct experimentally or a computationally expensive task for ab initio methods. The study demonstrates and solidifies the potential of combining DFT calculations and ML models to predict experimental properties, especially those that are scarce and impractical to empirically acquire.

Investigating mechanism of enhanced anti-fouling performance of MXene modified Janus MD membrane by XDLVO theory combined with surface elemental integration method

Organic membrane fouling is a major obstacle to the application of membrane distillation in low surface tension wastewater treatment. Membrane modification might be an effective way to mitigate membrane fouling. This study mainly explored the mechanism of enhanced anti-fouling performance of the MXene modified PVDF membrane by applying XDLVO theory combined with surface elemental integration (SEI) method. The rough membrane surfaces were first reconstructed using fractal function. Then, the interaction energy between low surface tension substances and the membranes before and after modification was calculated. The results showed that oil droplets and surfactant fouling were mainly caused by hydrophobic attraction due to Lewis acid-base (AB) interaction energy. By modifying the virgin PVDF membrane with MXene nanoparticles, the polar component of membrane surface tension (γAB) increased significantly, so that the interaction energy between all contaminants and membrane surface changed from attraction to repulsion. In addition, roughness weakened the interaction energy between contaminants and membrane surface but significantly lengthened the range of interaction distance, which together determined the ability of the membrane to attract or repel the contaminants. These findings may improve the understanding of the structure-effect relationship between membrane modification and anti-fouling ability, and provide new insights into the membrane modification for MD.

Coordination polymer-reinforced composite polymer electrolyte for all-solid-state Li-metal batteries

Composite polymer electrolytes (CPEs) have garnered significant interest due to their lightweight, flexible, and suitability for large-scale processing. However, current CPEs still face challenges such as unsatisfactory ionic conductivity (σ), low Li+ transference number (t+), and poor interfacial stability. This study presents the synthesis of a coordination polymer by coordinating Co2+ with terpyridine-end-capped polyethylene glycol (Co(tpy)-PEG). The resulting Co(tpy)-PEG-reinforced PEO-based CPE exhibits exceptional properties, including a high σ of 0.22 mS cm−1, large t+ of 0.75, and superior durability in both Li|Li (1400 h at 0.2 mA cm−2) and Li|LiFePO4 cells (70% capacity retention after 1000 cycles at 1C) at 60 °C, comparable to the best available CPEs. The incorporation of Co(tpy)-PEG filler plays a vital role in enhancing the σ by disrupting the PEO crystallinity and creating additional Li+ conducting pathways. Additionally, it can free Li+ to increase t+ through Lewis acid-base interactions between Co2+ and TFSI−/O atoms, as well as NO3− and Li+. Furthermore, Co(tpy)-PEG facilitates the formation of a stable multicomponent solid electrolyte interphase containing beneficial Li2Sx, LiF, and Li3N. This work introduces a promising strategy for designing and preparing multifunctional fillers capable of simultaneously reinforcing the σ, t+, and interfacial stability of CPEs.

High-Performance Room Temperature Ammonia Sensors Based on Pure Organic Molecules Featuring B-N Covalent Bond.

Exploring organic semiconductor gas sensors with high sensitivity and selectivity is crucial for the development of sensor technology. Herein, for the first time, a promising chemiresistive organic polymer P-BNT based on a novel π-conjugated triarylboron building block is reported, showcasing an excellent responsivity over 30000 (Ra/Rg) against 40ppm of NH3, which is ≈3300 times higher than that of its B-N organic small molecule BN-H. More importantly, a molecular induction strategy to weaken the bond dissociation energy between polymer and NH3 caused by strong acid-base interaction is further executed to optimize the response and recovery time. As a result, the BN-H/P-BNT system with rapid response and recovery times can still exhibit a high responsivity of 718, which is among the highest reported NH3 chemiresistive sensors. Supported by in situ FTIR spectroscopy and theoretical calculations, it is revealed that the N-H fractions in BN-H small molecule promoted the charge distribution on phenyl groups, which increases charge delocalization and is more conducive to gas adsorption in such molecular systems. Notably, these distinctive small molecules also promoted charge transfer and enhanced electron concentration of the P-BNT sensing polymer, thus achieving superior B-N-containing organic molecules with excellent sensing performance.

High-performance SPEEK composite membrane with ultrahigh selectivity enabled by sulfonated PANI for vanadium flow battery

The sulfonated poly(ether ether ketone) (SPEEK) composite membranes (S/SPANI) are prepared by blending sulfonated polyaniline (SPANI), which was synthesized through a post-sulfonation method. With the SPANI contents varying from 1 to 4 wt%, the S/SPANI membranes exhibit excellent physicochemical properties and cell performance, and at loading 3 wt% SPANI, S/SPANI-3 presents a higher proton conductivity (43.3 mS cm−1) and superior ion selectivity (49 × 103 S min cm−3) against SPEEK and Nafion 212. Moreover, its outstanding coulombic efficiency (95.9–98.4%) and energy efficiency (EE: 80.4–70.2%) at the current density of 100–200 mA cm−2 demonstrate an optimized tradeoff of proton conductivity and vanadium ion permeability. The performance optimization guarantees enhanced durability for 600 cycles and stable EE (76%) at 150 mA cm−2, which originated from the acid-base interaction, synergistic proton network, and interconnected chain structure. So, this provides a facile method to develop high-performance membranes by introducing desirable controllable topological molecular chains to construct synergistic proton transportation networks.

Confining Polymer Electrolyte in MOF for Safe and High-Performance All-Solid-State Sodium Metal Batteries.

Nanoconfined polymer molecules exhibit profound transformations in their properties and behaviors. Here, we present the synthesis of a polymer-in-MOF single ion conducting solid polymer electrolyte, where polymer segments are partially confined within nanopores ZIF-8 particles through Lewis acid-base interactions for solid-state sodium-metal batteries (SSMBs). The unique nanoconfinement effectively weakens Na ion coordination with the anions, facilitating the Na ion dissociation from salt. Simultaneously, the well-defined nanopores within ZIF-8 particles provide oriented and ordered migration channels for Na migration. As a result, this pioneering design allows the solid polymer electrolyte to achieve a Na ion transference number of 0.87, Na ion conductivity of 4.01×10-4 S cm-1, and an extended electrochemical voltage window up to 4.89 V vs. Na/Na+. The assembled SSMBs (with Na3V2(PO4)3 as the cathode) exhibit dendrite-free Na-metal deposition, promising rate capability, and stable cycling performance with 96 % capacity retention over 300 cycles. This innovative polymer-in-MOF design offers a compelling strategy for advancing high-performance and safe solid-state metal battery technologies.