Ionic covalent organic frameworks (iCOFs) have become promising platform materials for advanced proton exchange membranes (PEMs). However, the issue of interfacial defects often leads to discount of the intrinsic high proton conductivity of iCOFs. Here is the first attempt to engineer a bi-continuous mixed-dimensional proton exchange membrane by tightly confined stacking TpPa-SO3H iCOF nanosheets (iCONs) within the preswelled sulfonated poly(ether ether ketone) (SPEEK) nanofiber "shrinkable networks". The one-dimensional nanofibers and the densely packed two-dimensional iCONs domains interlocked each other, enhancing the ionic and hydrogen-bond interactions between fiber and iCONs. Forming interfacial defect-free microstructure and three-dimensional hydrogen bond networks throughout the membrane deliver high proton conductivity of 245.9 mS cm(-1) and low swelling ratio below 8 % at 80 degrees C. Compared with the self-standing TpPa-SO3H membrane, the flexible nanofiber network endows TpPa-SO3H/SPEEK membrane with 6.0-fold of elongation at break, and 5.4-fold of peel strength at the membrane-catalyst layer interface. The H2/O2 fuel cell achieves a remarkable peak power density of 2088.6 mW cm(-2), demonstrating superiority over recently reported iCOFbased PEMs. This work provides a feasible strategy for converting the intrinsic proton conductive advantages of iCOF into superior fuel cell performance.

Covalent organic frameworks (COFs) are expected to break through the trade-off between proton conduction and vanadium ion permeation in ion conductive membranes, however, maximizing intrinsic benefits of the nanoscale COF materials in polymer-based membranes remains a challenge. Herein, the ionic cluster in the membrane acts as a template to create a unique morphology of COF/ionic cluster intergrown ion conductive channel. The ionic cluster template anchors tris (4-aminophenyl) amine (TAPA) monomer through multiple hydrogen bond interactions with sulfonic acid groups during the casting of the sulfonated polybenzimidazole (SPBI) membrane, inducing the intergrowth of TpTAPA-COF nanoparticles with ionic clusters. The intergrown COF/ionic cluster microphase significantly increases the size of hydrophilic ion conductive channel from 5-8 nm to 20-30 nm with only about COF content of 1 wt%, and establishes vanadium ion sieving networks through the 6 & Aring; pores of TpTAPA-COF. This leads to a high ion selectivity of the SPBI/COF-1 % membrane (8.1 x 109 mS s cm- 3), about 3.9 folds that of Nafion 212 (2.1 x 109 mS s cm- 3). The corresponding vanadium redox flow battery (VRFB) shows a high energy efficiency of 82.3 % at 200 mA cm- 2 and maintain stable cycling performance over 800 cycles without change in chemical structure. The design of COF/ionic cluster intergrown microstructure provides an effective strategy for incorporating COFs into polymer matrix.

Constructing vertically aligned, penetrating metal-organic framework (MOFs) gas transfer pathways within mixed matrix membranes (MMMs) is an effective strategy for optimizing gas transport under low filler loading (<= 25 wt.%). Herein, we developed a novel "stack-polymerize-section" process to construct vertically aligned ZIF-8 pathways in MMMs by tailoring the density and channel size of PAN@ZIF-8 NFM for optimizing CO2 ultrafast and in-parallel transport. The designed XLPEO/PAN@ZIF-8 MMM exhibits excellent performance far exceeding the 2019 McKeown upper bound, with CO2 permeability and CO2/N2 selectivity of 369.2 Barrer and 90.0, respectively. Meanwhile, a novel parallel computational model that synergistically integrates the Maxwell model with resistance-based (RB) model methodology was proposed to introduce the interfacial resistance coefficient derived from polymer-MOFs interface heterogeneous concentration gradients. This work demonstrates the potential of vertically aligned MOFs channels for high-performance gas separation, providing a scalable and controllable fabrication pathway for maximizing the efficiency of MOFs in membrane technology.

Saline droplet evaporation constitutes a fundamental physicochemical phenomenon with critical applications in separation technologies, desalination processes, and crystal engineering. This investigation elucidates circulation mechanisms during saline droplet evaporation through systematic examination of various geometrical configurations and thermal conditions. A computational fluid dynamics approach validated through optical visualization and infrared thermal imaging revealed distinct circulation regimes governed by the interplay between Rayleigh convection and Marangoni effects. At ambient conditions, droplets exhibited predominantly Rayleighdriven convection, with contact angles below 90 degrees generating peripheral deposition patterns while angles exceeding 90 degrees produced centralized crystal accumulation due to non-uniform evaporation flux distribution. Temperature modulation induced substantial flow pattern transitions at specific critical thresholds, with thermal Marangoni effects overriding Rayleigh convection when temperature differences exceeded 0.94 K for droplets with 120 degrees contact angles. Circulation transitions manifested more prominently in droplets with larger contact angles, characterized by progressive transformation from Rayleigh-driven clockwise flows to thermal Marangonidriven counterclockwise patterns. Interfacial heat transfer coefficients exhibited deterministic influence on circulation dominance, with values below 10 W/m2 & sdot;K maintaining Rayleigh-dominated flow and values between 100-1000 W/m2 & sdot;K establishing thermal Marangoni dominance. A comprehensive phase diagram correlating dimensionless Rayleigh and Marangoni numbers to circulation patterns was developed, providing predictive capability for flow regime transitions under varying evaporation conditions. The established quantitative relationships between thermal parameters and circulation mechanisms enable precise control of crystal deposition morphologies through interfacial thermal regulation.

Anion-exchange ionomers (AEIs) serve as catalyst binders and hydroxide conductors in anion-exchange membrane fuel cells (AEMFCs), yet conventional bulk-membrane-derived AEIs often fail to meet the transport and interfacial demands of ultrathin catalyst layers. Herein, hydroxyl-rich polynorbornene-based AEIs were developed to construct coupled dual-domain OH- transport pathways. N+-rich ionic domains facilitate charge-driven ion conduction, while densely distributed hydroxyl groups establish continuous hydrogen-bonding networks to bridge nanoscale discontinuities and suppress swelling. The optimized QA-HPNB-25% achieves an OH- conductivity of 93.64 mS cm-1 at 80 degrees C, a low swelling ratio of 10.4%, and over 90% conductivity retention after 1000 h in 1 M KOH at 80 degrees C. At an ionomer-to-carbon ratio of 0.3, it balances ion transport, interfacial wetting, and gas accessibility, delivering a peak AEMFC power density of 657.91 mW cm-2. These results highlight that nanoscale ion-channel architecture and interfacial ionomer organization are critical to AEI performance in ultrathin catalyst layers.

The trade-off between chemical stability and proton selective conduction greatly influences energy efficiency and cycling stability of vanadium redox flow batteries (VRFBs). Herein, the electron-withdrawing side chain protective engineering was proposed. Owing to the electron-withdrawing effect of the trifluoromethyl and carboxylic acid contained side chain, the sulfonic acid groups (-SO3H) were located on the main chain benzene ring with enhanced proton dissociation ability, the electrostatic potential of benzene hydrogen atoms increased to repel vanadium ions, and the HOMO-LUMO gap was enlarged for excellent oxidation energy barrier, simultaneously improving H+/Vn+ selectivity and chemical stability of the sulfonated poly(arylene) membrane (SPTPC). Both low area resistance (0.2 Omega cm2) and vanadium permeability (1.1 & times; 10-9 cm2 s-1) led to high H+/Vn+ selectivity (5.54 & times; 1010 mS s cm-3) in the SPTPC membrane. The corresponding VRFB achieved high energy efficiency of 80 % @280 mA cm-2, extremely low discharge capacity decay rate of 0.027 % and long-term stable operation of 7000 charge-discharge cycles at 200 mA cm-2. A degradation mechanism was proposed that attributed the excellent cycling stability to the preferential degradation of electron-withdrawing side chain as a sacrifice structure.

Ultrathin SCOF continuous membrane is fabricated by ionic fiber network reinforced strategy. SCOF – SPBI fiber bi-continuous microstructure enhances toughness and proton transport network. At the same time, it achieves high fuel cell performance.

Hierarchically porous membrane presents an effective solution to address the trade-off effect between proton(H+) conduction and proton/vanadium ions(H+/Vn+) selectivity for high performance vanadium redox flow batteries(VRFBs). However, conventional hierarchically porous membrane suffers from low H+/Vn+ selectivity in meso-/macro pores and high proton transport resistance in sub-nano pores, which limit further improvement of the trade-off effect. Herein, a confined sub-2-nm sulfonated covalent organic framework(SCOF) layer was grown in-situ through the hydroxyl ion clusters of the hierarchical porous substrate membrane(PBIOH-P, based on polybenzimidazole), resulting in its formation both within the meso-/macropores and on the sub-nano pore surfaces. This confined-SCOF-functionalized hierarchical porous membrane(PBITP) exhibits proton-specific recognition effect, originating from the boosted confined electric charge, which enhances both electrostatic energy and hydrogen-bonding energy in hierarchical porous regions. Much lower proton adsorption energy(-296.96kJmol-1) and 1.65 folds diffusivity comparing to vanadium ions make protons preferentially be recognized during the competitive adsorption between H+ and Vn+, and substantially accelerate the diffusion through the PBITP membrane. Extremely high H+/Vn+ ion selectivity(3.93×1012 mS s cm-3) leads to excellent energy efficiency(80.1% @340mAcm-2) and low discharge capacity decay rate(0.06%/cycle @100mAcm-2) in VRFB. The confined-SCOF-functionalized hierarchical porous membrane presents the promising candidate for next generation VRFBs.

Chemical structure design of the functional side chains is essential to ion selective channels in ion conductive membranes, significantly affecting the efficiency of vanadium redox flow batteries (VRFBs). Herein, a novel camphorsulfonic acid group has been proposed as a bulky, non-coplanar proton conductive functional side chain, and grafted onto sulfonated polybenzimidazole (SPBICa). It helps to weaken the tight packing of the polymer chains, not only improving the self-aggregation ability of the sulfonic acid groups to form a larger ionic cluster (8.97 nm) than that of the pristine SPBI (7.85 nm), but also creating free volume (sizes concentrated in 1-3 & Aring;) with proton/vanadium ion sieving capabilities. The interconnected microphase-separated channels couple with free volume sieving pathways, demonstrating excellent properties. The SPBICa-1.10 membrane, with a camphorsulfonic acid grafting degree of 110%, achieves high proton conductivity of 53.3 mS cm-1, extremely low area resistance of 0.14 Omega cm2 and vanadium ion permeability of 1.97 & times; 10-9 cm2 s-1. Consequently, the membrane exhibits a remarkable ion selectivity of 27.1 & times; 109 mS s cm-3, approximately 49.5 fold that of the commercial Nafion 212 membrane. The VRFB assembled with the SPBICa-1.10 membrane achieves an energy efficiency of 81.3% at a high current density of 200 mA cm-2. After 650 charge-discharge cycles, the battery demonstrated a very low capacity decay rate of only 0.15% per cycle, significantly outperforming batteries using the SPBI and Nafion 212 membranes. This work provides an efficient molecular design strategy for highly selective and stable ion conductive membranes in VRFB applications.

The trade-off between permeability and selectivity remains a major challenge in developing nanofiltration membranes for the treatment of antibiotic-contaminated wastewater. Herein, we present an acetic acid activation method to reconstruct the morphology and pore size of polyamide membranes. The acetic acid induces swelling of the polyamide network and dissolves oligomers, thereby generating additional free volume, and creating new interconnections within the polymer matrix. This process simultaneously reduces the thickness of the selective layer from 81.6 nm to 40.8 nm while maintaining its structural integrity. Molecular simulations reveal a strong affinity between acetic acid and polyamide chains, which drives polymer swelling and increases free volume. Following treatment with dilute acetic acid, the water permeance of the polyamide membrane increased from 15.9 L center dot m- 2 center dot h- 1 center dot bar- 1 to 21.5 L center dot m- 2 center dot h- 1 center dot bar- 1. This work outlines a potential approach to fabricating high-flux nanofiltration membranes, enabling efficient antibiotics separation and sustainable wastewater purification.

Vanadium redox flow batteries (VRFBs) are considered promising systems for large-scale energy storage, however, limited by low power density that is closely relates to sluggish electrode kinetics. Herein, a single-atom bismuth catalyst supported on W18O49 nanowires (Bi/W18O49@GF-2) was designed. The strong coordination and embedding of Bi single atoms into the W18O49 lattice not only modulate the local coordination environment and stimulates the formation of abundant highly active oxygen vacancies, but its reconfigured local electronic structure also significantly elevates the energy barrier for the parasitic hydrogen evolution reaction (HER). This dual-modulation mechanism drastically improves the reversibility of the V3+/V2+ redox reaction and diminishes polarization. The VRFB assembled with Bi/W18O49@GF-2 achieves a remarkable energy efficiency of 77.6% at 300 mA cm- 2, and an exceptionally low energy efficiency decay rate of 0.0016% per cycle over 3000 cycles. The experimental results and density functional theory simulations reveal that Bi atoms induce Bi-O-W configurations and oxygen vacancy, which construct efficient charge-transfer channels and facilitate adsorption of vanadium species and stability of catalytic sites. This study highlights the potential of oxygen vacancy mediated single-atom engineering in advancing VRFB electrode design, and offers theoretical insights into the catalytic mechanism at the atomic scale.

Bipolar membrane (BPM) electrodialysis coupled with in situ Mg(OH)2 precipitation is promising for Li/Mg separation but is limited by a severe separation-fouling trade-off. Here, molecular dynamics simulations using an interface model comprising polybenzimidazole-based anion exchange membrane (AEM) layer and brine were conducted to elucidate the molecular mechanism underlying this coupled precipitation-separation process. Operating conditions (electric-field strength) and BPM properties (water-dissociation rate and cationic content in AEM layer) primarily regulate OH- generation and transport, whereas brine composition mainly determines the Mg2+ coordination environment and precipitation tendency. These factors jointly control Mg-OH coordination and local supersaturation, thereby shifting Mg(OH)2 nucleation among the bulk, interface, and membrane phase, determining separation performance and scaling risk. Strengthening OH- delivery via higher electric-field strength or faster water dissociation enhances Mg2+ removal but tends to displace precipitation toward interfacial/intramembrane regions, while higher cationic content of AEM layer strengthens Mg2+ exclusion, favors bulk precipitation. Salinity further modulates anion-OH- competition and the driving force for Mg2+ accumulation, while the Mg/Li ratio exerts a comparatively minor effect within the investigated range. These insights provide molecular-level guidance for designing membranes and operating strategies that match OH- supply with robust Mg2+ exclusion to achieve high separation with low fouling.

The proton (H+) and vanadium ion (Vn+) selectivity of proton-conductive membrane is one of the key components for vanadium redox flow batteries (VRFBs). In this work, a hydrophobic side chain was designed to accelerate proton conduction with high selectivity of H+ and Vn+ for the VRFB membrane. The grafting of hydrophobic butyl side chains into the membrane (PBIOSO3-But) induced the formation of a high microphase separation capacity to form large and connected ion conductive channels with low ion exchange capacity (IEC). As a result, the PBIOSO3-But membrane with low IEC of 1.26 mmol g-1 shows area resistance of 0.19 Ω cm2 as well as vanadium permeability of 3.2 × 10-9 cm2 s-1, leading to a high H+/Vn+ selectivity of 2.51 × 1010 mS s cm-3 (higher than Nafion 212, 4.62 × 108 mS s cm-3). Notwithstanding its low ion-exchange capacity, this membrane demonstrates H+/Vn+ selectivity surpassing that of recently reported microphase separation membranes. Compared to the Nafion 212 membrane (74.3% EE; 0.81% per cycle), the PBIOSO3-But membrane exhibited superior VRFB performance, achieving an energy efficiency of 83.2% at 200 mA cm-2 and a low retention rate of 0.22% per cycle. These values compare favorably with those of recently reported membranes.

The development of low-loading precious metal-based electrocatalysts for hydrogen evolution reaction (HER) remains a research priority and technical challenge, requiring the effective utilization of robust interfacial interactions and synergistic effects between metal clusters and corresponding supporting substrates. Herein, a highly active electrocatalyst for hydrogen evolution with iridium (Ir) clusters boosted on oxygen-deficient tungsten oxide (W18O49) support is proposed via a one-pot hydrothermal strategy. The 1.16 wt% Ir/W18O49 catalyst demonstrates a low overpotential of 33 mV at 10 mA cm- 2, along with superior Ir mass activity (13.9 A mg-1) at - 50 mV versus reversible hydrogen electrode (vs. RHE) that surpasses Ir/C, commercial 20 wt% platinum on carbon (Pt/C), and most reported precious metal-based catalysts. Theoretical calculations reveal that the synergistic modulation of electron transfer from Ir clusters to the W18O49 support and the hydrogen spillover effect regulate the hydrogen adsorption and desorption, thus enhancing the HER performance.

Anion exchange membranes (AEMs) are key components in emerging energy technologies, yet their development is hindered by the challenge of simultaneously achieving high hydroxide conductivity and durable alkaline stability. These properties are governed by multiscale, coupled effects of polymer architecture, microphase separation, and operating conditions, making AEM exploration slow and largely empirical. Here, we propose SPARK, a structure-property graph attention network with prior knowledge of chemistry embedding, to accelerate AEM molecular design through robust candidate prioritization and mechanism-relevant interpretability. SPARK embeds chemical prior knowledge into molecular graphs and employs a dual-channel architecture that separately encodes hydrophilic ionic and hydrophobic non-ionic segments, explicitly capturing microphase separation and ion-transport channel formation. It translates AEM structures into five-level performance grades for hydroxide conductivity and alkaline stability with high accuracy, outperforming conventional machine-learning baselines. Attention-based interpretation further pinpoints structural units associated with ion transport and alkaline degradation, providing actionable guidance to mitigate the conductivity-stability trade-off. Finally, SPARK is validated by pre-grading to-be-synthesized AEM candidates with good agreement to experiments, and the accompanying software package is publicly released to facilitate broader adoption and data-driven AEM design.

Covalent organic frameworks (COFs) possess highly ordered ionic conductive channels to compensate the challenges of polymer materials, are expected to address the critical issue of ion selective conduction in vanadium redox flow batteries (VRFBs). In this work, the amphoteric COFs nanofibers ion selective channel network is designed for the first time through the in-situ growth of the triazine COF and sulfonated COF from monomers contained electrospun blend nanofibers, and then densified by sulfonated polybenzimidazole (SPBI). The amphoteric COF nanofibers show notably higher diffusivity ratio of proton to vanadium ions compared to the individual nanofiber, demonstrating synergistical effect to construct high ion selective channel network, in which the triazine COF fiber repels vanadium ions via Donnan effect of the protonated nitrogen contained channels, and the sulfonated COF fiber facilitates rapid proton hopping along the acidic sulfonic acid groups contained fiber network. With amphoteric COFs nanofibers content of 55 vol%, the composite membrane exhibits low area resistance (0.17 Ω cm2) and vanadium ions permeation (3.9 × 10−9 cm2 s−1) simultaneously, achieving an impressive battery energy efficiency of 85.1% at 200 mA cm−2, outperforming that of the Nafion 212 (74.9%) and currently reported amphoteric ion conductive membranes for VRFBs. The amphoteric COFs composite membrane also shows stable operation over 1500 cycles (with periodic electrolyte refresh), exhibiting a discharge capacity decay rate of 0.25% per cycle (calculated over the first 100 cycles). This study provides an effective microstructure design for COFs materials to improve ion selectivity and flow batteries performance.

Alkaline anion exchange membranes (AEMs) are crucial for electrochemical devices, such as fuel cells and water electrolyzers, demanding both high conductivity and alkaline stability. However, their development relied on labor-intensive trial-and-error methods. Here, a computational refinement and yielding system for top-class AEMs (CRYSTAL) was developed. This system generates novel AEM structures, which are then refined using prediction models, enabling an integrated and intelligent design process. Utilizing a Transformer-based architecture with multi-head self-attention mechanism, CRYSTAL effectively analyzes structural sequences, extracting high-dimensional molecular features and contextual relationships. This attention-enhanced framework ensures efficient and reliable structural generation while maintaining high-precision predictive performance (R-2 > 0.9). Ultimately, CRYSTAL screened over 10 million potential AEM candidates, identifying 1629 structures with hydroxide conductivity exceeding 175 mS/cm and providing ten representative high-performance structures. This framework demonstrates transformative potential, significantly accelerating the discovery of advanced AEMs and establishing a scalable pathway for next-generation polymer technologies.

Poly(norbornene)s (PNBs) are great potential candidates for anion exchange polyelectrolytes (AEPs), however, PNBs-based AEPs usually suffer from excessive water sorption. Herein, the underlying mechanism behind high water sorption was proposed by using the quaternized PNBs as a model AEP. With a moderate ionic content of 2.15 mmol/g, the hydrogenated AEP has a high water uptake of 253 % at 25 degrees C, which is caused by heterogeneous quaternization and weak interchain interactions. When the brominated AEP was immersed in trimethylamine aqueous (TMA/H2O) 2 O) solution, TMA penetrates tightly packed polymer chains, seriously destroying vdW interchain interactions. Subsequently, the quaternized cationic groups induce spontaneous water sorption. Although ionic moieties possess strong interchain electrostatic interactions, the solid AEPs restrict polymer chains to form highly cohesive domains for resisting water sorption. Additionally, carbon-carbon double bonds in the PNBs preferentially interact with TMA/H2O, 2 O, further increasing water uptake. This work provides theoretical guidance for preparing high-performance AEPs based on all-hydrocarbon aliphatic backbones.

The performance upper bound of mixed-matrix membranes (MMMs) stems from discontinuous filler dispersion and impaired transfer kinetics. Herein, we propose to construct 3D interpenetrating covalent organic frameworks (COFs) architecture synergizing physisorption and rapid gas molecular transport to enhance CO2 separation. Electrospun polyacrylonitrile (PAN) nanofibers induce the heterogeneous epitaxial growth of functionalized TpPa-1/TpPa-SO3H to create a bi-continuous transport highway with (i) 3D-interconnected micropores (similar to 1.8 nm) for low-resistance diffusion and physical adsorption and (ii) multi-channel chemisorption via CO2-philic groups (such as amino, hydroxyl, and sulfonic acid). Resultantly, the CO2 permeability and CO2/N-2 selectivity of the prepared PEO/HPAN@TpPa-SO3H3 MMM were improved by 32.02 % and 62.18 %, respectively, compared with the direct-blending PEO/TpPa-SO3H-14.90 wt% membrane. The electrospun-based nano-network assembly establishes a material paradigm for overcoming the physico-chemical adsorption-diffusion trade-off in gas separation membranes.

High selective conduction of ion conductive membrane is essential to efficiency and cycling stability of vanadium redox flow battery, however, disentanglement of the trade-off between proton conductivity and vanadium ions permeability is challenging. In this work, the ortho-phenol side chain with vanadium ion recognition effect is proposed, which can effectively reduce vanadium ions permeability through coordinated chelation of vanadium ions. The ortho-phenol hydroxyl side chain, together with the sulfonic acid group, can also construct a microphase separation proton conductive channel to promote proton conduction. As the ion exchange capacity of ortho-phenol hydroxyl group (IECOH) in sulfonated polybenzimidazole reaches 2.89 mmol g- 1 (SPBIOH-2.89), low area resistance (0.21 Omega cm2) and vanadium ions permeability (1.71 x 10-9 cm2 s-1) are achieved. Accordingly, the H+/Vn + selectivity presents 1.81 x 107 S s cm-3, around 72.8 folds that of commercialized Nafion 212 membrane (2.49 x 105 S s cm-3). The VRFB assembled with SPBIPhOH-2.89 membrane presents excellent performance (energy efficiency 80.1 % at 200 mA cm- 2 and discharge capacity decay rate 0.26 % per cycle at 100 mA cm- 2), superior to that of Nafion 212 (66.7 % at 200 mA cm- 2, 0.71 % per cycle at 100 mA cm- 2). The membrane performance is in top level compared with most reported amphoteric ion conductive membranes.