Browse Articles

Machine Learning‐Guided Design of a Flexible Highly Conductive Additive‐Free Polymer Cathode

ABSTRACT Organic cathode materials (OCMs) are promising sustainable alternatives to inorganic counterparts for next‐generation batteries, yet their widespread application is largely hindered by intrinsically low electrical conductivity (below 10 −6 S cm −1 ) and material dissolution. The vast chemical space for exploration complicates the discovery of optimal OCMs. In this work, we utilized a machine learning (ML)‐based discovery process with a pretrained transformer model in ZINC organic molecules database, yielding a couple of potential high‐performance OCMs candidates, including isoindigo‐type redox units. The output of such efficient screening inspires the design of poly‐benzodifurandione (PBFO) as a free‐standing cathode material for high‐performance Li‐ion and Na‐ion storage. The flexible PBFO film exhibits a breakthrough conductivity of 5.9×10 2 S cm −1 , setting a new benchmark for additive‐free organic cathodes. The neat PBFO cathodes achieve a reversible capacity of 262 mAh g −1 averaging at 2.5 V versus Li + /Li at 25 mA g −1 , delivering a high electrode‐level energy density of 655 Wh kg −1 , among the highest reported for OCMs. This work provides the first flexible, high‐conductivity organic cathodes without conductive additives and binders, opening a new direction toward viable organic batteries.

Intrinsic Elastification of Ferroelectric Poly(vinylidene fluoride) Homopolymers

ABSTRACT Elastic ferroelectrics, distinguished by their softness, stretchability, and ferroelectric and piezoelectric responses, are promising candidates in next‐generation wearable electronics. Currently, the intrinsic elastification of ferroelectric polymers has been achieved through a “slight crosslinking” strategy, which relies on costly poly(vinylidene fluoride) (PVDF)‐based copolymers with low Curie temperatures, thereby limiting their operation at high temperatures. In contrast, PVDF homopolymers are low‐cost and possess an inherently high Curie temperature, while their high modulus has long hindered elasticity. Here, we overcome these limitations by introducing highly reactive, soft long‐chain crosslinkers into PVDF homopolymers, enabling simultaneous low cost, high thermal stability, and intrinsic elasticity. By tuning the crosslinking density, intrinsically elastic ferroelectrics based on PVDF homopolymer were obtained with over 80% elastic recovery under 60% strain. Remarkably, the materials retain a high remanent polarization ( P r ) of 7.00 µC/cm 2 at 110°C. The materials maintain stable ferroelectric responses even under strains up to 70%. This study resolves the long‐standing challenge of elastifying high‐modulus PVDF homopolymers and develops a low‐cost, thermally robust, intrinsically elastic ferroelectric. These advances outline a promising pathway toward next‐generation wearable electronics that demand both high elasticity and high‐temperature operation.

Synergistic Ion‐Pair/Lewis Acid Catalysis Enables Enantioselective Synthesis of Helically Chiral Oxa[6]Helicenes

ABSTRACT Helicenes are privileged chiral architectures with exceptional optical and electronic properties, underpinning their importance in asymmetric catalysis, optoelectronics, and supramolecular chemistry. Despite significant progress in helicene synthesis, strategies for extending peripheral aromatic rings to access structurally diversified helicenes remain elusive. Here we report a synergistic catalytic system integrating a bifunctional phosphonium salt (BPS) with silver, which enables a highly efficient [4 + 2] cyclization/aromatization cascade to directly construct a new family of oxa[6]helicenes. This cooperative catalysis exhibits broad substrate scope, delivering chiral helicenes in excellent yield and enantioselectivity. Mechanistic studies reveal that Ag + activates the cyano group, while the BPS catalyst engages through hydrogen bonding and ion‐pairing interactions to form a unique sandwich‐type transition state. This dual activation mode provides a powerful framework for constructing helicenes with tailored structural diversity, paving the way for future applications in chiroptical materials and enantioselective catalysis.

The Simplest Phosphinylperoxy Radical and Its Isomers in the Photochemical Phosphorus‐Hydrogen‐Oxygen Network

ABSTRACT The oxidation of phosphine (PH 3 ) plays an important role in the photochemical phosphorus‐hydrogen‐oxygen network of the Earth's atmosphere. The phosphinyl radical (•PH 2 ) is a key intermediate in the photochemistry of PH 3 , and its reactions with O 2 yield phosphorus oxyacids as stable reservoirs via the intermediacy of yet elusive radicals. Herein, we report the identification of the simplest phosphinylperoxy radical H 2 POO• in gas phase reaction between •PH 2 and O 2 . The characterization of H 2 POO• with matrix‐isolation IR and UV‐vis spectroscopy is supported by D‐ and 18 O‐isotope labeling experiments and quantum chemical calculations. Upon photoexcitation at 410 nm, the matrix‐isolated H 2 POO• undergoes successive hydrogen‐migration to form two isomers HP(O)OH• and •P(OH) 2 . Further UV‐irradiation at 365 nm causes decomposition to yield the water complex of phosphorus monoxide (•PO), which can be photolytically converted to metaphosphorous acid (HOPO). The disclosed photochemistry of these novel phosphorus‐bearing molecules helps in understanding the photochemical network of PH 3 in the atmospheric and interstellar phosphorus chemistry.

Bioinspired Mo‐on‐Cu Nanosheets Enable Potential‐Dependent Electrosynthesis of Urea and Methanol via Interfacial Electron Redistribution

ABSTRACT The electrochemical reduction of CO 2 and its co‐reduction with NO 3 − ions provide green pathways for the sustainable synthesis of methanol and urea; however, achieving the selective production of both compounds at low potentials remains a challenge. Inspired by natural Mo‐containing enzymes, we develop Mo‐on‐Cu nanosheets (Mo‐Cu NSs) via electrochemical reduction of CuO NSs followed by Mo deposition through electron‐beam evaporation. The bioinspired Mo‐Cu NSs deliver outstanding activity, achieving a urea partial current density of 2.39 mA cm −2 with a Faradaic efficiency (FE) of 52% at −0.2 V versus RHE, and a methanol FE of 65% at −0.5 V versus RHE, ranking among the most efficient electrocatalysts for co‐synthesis of urea and methanol. In situ electrochemical characterizations and density functional theory (DFT) calculations reveal that interfacial electron redistribution between electron‐rich Cu and electron‐deficient Mo optimizes intermediate conversion pathways, thereby enabling potential‐dependent product selectivity. Specifically, *CO 2 and *NOH coupling accounts for urea formation, while *NO intermediates promote methanol production. This study not only provides a new electrocatalyst for highly efficient urea and methanol electrosynthesis but also can guide the design of other electrocatalysts for high‐value chemicals.

Electrolyte‐Regulated Conversion of Small Resource Molecules

ABSTRACT Electrocatalysis powered by renewable electricity is a promising strategy for clean energy transformation and achieving carbon neutrality goals. In resource molecules conversion (e.g., CO 2 and NO 3 − ), electrolytes serve multiple roles as reaction media, proton donors, and mass‐transport carriers, with their composition and physicochemical properties exerting a significant influence on reaction pathways, intermediate stability, and product selectivity. Most research endeavors have predominantly concentrated on catalyst design, often oversimplifying electrolytes as inert backgrounds. This minireview proposes a classification framework for electrolyte effects into short‐, medium‐, and long‐range interactions, highlighting their active regulatory roles at electrified interfaces. A comprehensive overview is provided of recent advancements in methodologies for investigating solvent effects, accompanied by an in‐depth analysis of representative electrocatalytic systems. This analysis elucidates how the composition of electrolytes influences molecular‐level elementary reaction steps, the dynamic reorganization and equilibrium of the interfacial microenvironment, as well as macroscopic catalytic performance, through a variety of distinct mechanisms. Finally, the key challenges and opportunities are also discussed, emphasizing electrolyte engineering as a strategic tool to reshape reaction environments and accelerate the practical deployment of electrocatalytic technologies.

Scalable Ru‐Doped Pt/NiFe‐LDH Catalyst via Pulse Electrolysis Enables Stable Glycerol Oxidation to Glyceric Acid at High Current Density

ABSTRACT Selective electrooxidation of glycerol (GLY) to glyceric acid (GLA) offers a promising route for GLY valorization but remains hindered by limited activity and stability. Herein, we report a scalable self‐corrosion strategy for large‐area fabrication of a Ru‐doped Pt/NiFe‐LDH catalyst on Ni foam (PtRu/NiFe‐LDH) with an area of up to 36 cm 2 . The incorporation of Ru modulates the electronic structure, enhances the adsorption of both OH − and GLY, and lowers the free energy barrier for OH* formation, thereby significantly boosting catalytic activity to achieve a recorded current density of 439.5 mA cm − 2 . Furthermore, pulse electrolysis effectively suppresses the formation of PtO x , ensuring long‐term stability. When integrated into a GLY oxidation‐assisted hydrogen evolution system, this bifunctional catalyst reduces the cell voltage by 1.01 V relative to conventional water splitting, while delivering 78.5% selectivity towards GLA and stable operation for over 120 h. This work establishes a viable pathway toward the industrialization of selective electrochemical oxidation of GLY to GLA by integrating advanced catalyst design with optimized electrolyzer configuration.

Proximity Engineering of Fe‒N ₄ Twins for Oriented Generation of Singlet Oxygen for Hospital Wastewater Treatment

ABSTRACT Precisely tailoring the molecular configurations of single‐atom sites and elucidating their correlation with generated specific reactive species is crucial for advancing Fenton‐like chemistry toward targeted remediation. Herein, we developed a facile approach to precisely modulate the distances between isolated Fe‒N 4 sites (d Fe–Fe ) from nanometer (0.95 nm) to subnanometer (0.43 nm) to construct a family of well‐defined Fe‒N 4 twins with manipulated ligand‐field strength and spin states. Different Fe‒N 4 twin sites trigger a metal‐loading‐independent volcano‐shaped Fenton‐like activity trend. The optimal configuration, achieved at an Fe‒Fe distance of 0.43 nm (Fe d0.43 SA), induces an intermediate‐spin (t 2g 4e g 1) configuration that optimizes e g orbital occupancy, thereby promoting peroxymonosulfate (PMS) adsorption to form *HSO 5 − and subsequently lowers the energy barrier for coupling with another PMS to selectively generate singlet oxygen ( 1 O 2 ). The robust molecular catalyst with Fe‒N 4 twin sites sustains over 120 h of continuous treatment of organic wastewater and demonstrates simultaneous disinfection and pharmaceutical removal of actual hospital wastewater. This work presents an advanced strategy for engineering single‐atom sites with multi‐site cooperativity to regulate Fenton‐like catalysis, enabling rapid and real‐world water purification.

Arylhydrazines: Convenient Homogeneous Reductants for Scalable Cross‐Coupling

ABSTRACT Reductive cross‐couplings have emerged as a powerful strategy for forging C–C bonds directly from electrophiles, circumventing the need for preformed organometallic reagents, yet they often suffer from limitations associated with heterogeneous reductants like Zn (e.g., poor reproducibility and scalability) or costly homogeneous alternatives such as TDAE. Inspired by prior explorations of hydrazide chemistry, we disclose arylhydrazines as inexpensive, readily available homogeneous sacrificial reductants that enable Ni‐catalyzed sp 2 ‐sp 3 cross‐coupling of aryl halides with secondary alkyl iodides under mild, operationally simple conditions using a Ni II precursor, bipyridine ligand, and hindered amine base. Optimization, substrate scope studies, and direct comparisons reveal superior yields and selectivity relative to Zn‐based methods, particularly for heterocyclic and electron‐rich partners, while calorimetry‐guided safety assessments and decagram‐scale demonstrations highlight enhanced thermal control, reproducibility, and practicality. Mechanistic investigations via UV–vis spectroscopy, 19 F NMR, and reaction calorimetry support a pathway involving hydrazine‐mediated Ni II reduction to initiate a Ni I /Ni III cycle, with benign byproducts (N 2 and arene), positioning arylhydrazines as versatile reagents for executing reductive coupling on scale.

Trimeric Acceptors with Fine‐Tuned Alkyl‐Linkage Sites for 20.23% Efficiency and Stable Organic Solar Cells

ABSTRACT Giant‐molecule acceptors (GMAs) have been proven to improve power‐conversion‐efficiency (PCE) and stability of organic solar cells (OSCs), while most high‐performance GMAs only attach two monomers and primarily exhibit the properties of their monomer precursors. Herein, we develop four trimeric GMAs (named 3Y‐site, including wing‐sites‐linked 3Y‐Wing, end‐sites‐linked 3Y‐End, hybrid wing/end‐sites‐linked 3Y‐EWE and 3Y‐WEW) with the same alkylated linker but different linking sites to fine‐tune molecular optoelectronic properties. Among them, 3Y‐Wing with a superior planarity and extensibility possesses broadened absorption, better crystallinity, superior packing, and higher glass transition temperature, resulting in an optimized phase separation. The optimized devices with binary PM6:3Y‐Wing and ternary PM6:L8‐BO:3Y‐Wing achieve both champion PCEs of 15.0% and 19.1%, respectively, along with enhanced light, thermal, and storage stabilities, outperforming devices based on all other 3Y‐site counterparts. In the classic D18:L8‐BO host system, the effectiveness of 3Y‐Wing in boosting PCE is further validated, and the resulted ternary devices deliver an excellent PCE of 20.23%, setting an efficiency record among the reported trimeric GMAs. Moreover, the 3Y‐Wing based OSCs offer a better balance of high PCE and stability, further distinguishing them within 3Y‐site series. Our developed wing‐sites‐linked trimeric 3Y‐Wing is a promising candidate to achieve both high device efficiency and stability.

Dynamic Self‐Organizing Lithium Bonds for High Energy Density Lithium Batteries

ABSTRACT To enhance the electrochemical performance of silicon electrodes, it is essential to comprehensively understand their underlying lithium storage mechanisms. Unfortunately, the vast diversity of silicon anode types and compositions complicates efforts to accurately predict and validate these reaction processes. Accordingly, a structurally well‐defined silicon‐based model compound is in great need. Thus, we select methacrylate polyhedral oligomeric silsesquioxane (MAPOSS) as the subject for studying the lithium‐silicon bonding mechanism due to its clear chemical structure and composition. Through detailed characterization of the morphological and chemical structural changes of MAPOSS before and after cycling, our results reveal an intriguing phenomenon: the synergistic interaction (here termed as “Dynamic Self‐Organizing Lithium Bonds”) between Si atoms in the core and carbonyl (C = O) groups in the side arms of MAPOSS promotes reversible dynamic Li + ions storage. Density functional theory simulations further support this deduction. Furthermore, MAPOSS is employed as a binder in graphite anodes after polymerization. At 0.2 C, the resulting half‐cell exhibits an impressive specific capacity exceeding 450 mAh g −1 over 250 cycles. This study demonstrates that the integration of MAPOSS into the full cell configuration allows for a reduction in the N/P ratio and is expected to improve the overall energy density of the battery.

Cation‐Vacancy Induced Compressive Strain Localization in RuO ₂ Catalyst for High‐Performance Acidic Oxygen Evolution

Abstract Designing acid‐stable RuO 2 catalysts capable of overcoming the activity‐stability trade‐off remains pivotal for advancing proton exchange membrane water electrolyzers (PEMWEs). Here, we introduce a cation‐vacancy engineering strategy to generate localized compressive strain in RuO 2 by electrochemically leaching Cd from a pre‐doped lattice. This strain modulation simultaneously elevates the Ru valence state (+4.35) and strengthens Ru─O covalent bonds, optimizing *OH/*O/*OOH adsorption energetics while suppressing over‐oxidation. The resulting V Cd ‐RuO 2 catalyst achieves an overpotential of 203 mV at 10 mA cm −2 in 0.1 M HClO 4 . Integrated into a PEMWE, it sustains >600 h operation at 200 mA cm −2 with a voltage degradation rate of 0.1 mV h −1 . The MEA based on V Cd ‐RuO 2 required cell voltages outperformed commercial RuO 2 by 120–180 mV at industrially relevant current densities (0.5–1.5 A cm −2 ), thereby demonstrating significant energy efficiency. Multiscale analyses confirm that compressive strain stabilizes high‐valence Ru sites through enhanced orbital overlap, reconciling catalytic activity with structural durability. This work establishes vacancy‐driven strain engineering as a universal approach for designing robust, Ir‐free OER electrocatalysts.

FeCoN ₆ Sites Unlock Superior Sodium‐Ion Storage Through Synergizing Capture‐Release and Orbital‐Mediated Charge Delocalization

ABSTRACT Sodium‐ion hybrid capacitors (SHCs) are severely hindered by sluggish sodiation kinetics in conventional anodes. Single‐atom sites, though promising, suffer from localized d ‐orbitals that induce overly strong Na + binding, creating a kinetic bottleneck. Herein, we design heteroatomic FeCo dual‐atom sites (FeCoN 6 ) that unlock a dual‐mechanism synergy for fast and durable Na + storage. Theoretical‐experimental evidence confirms that strong d–d orbital coupling induces an orbital‐mediated charge‐delocalization (OMCD) effect, which downshifts the d ‐band center to moderate Na + binding affinity. Meanwhile, the intrinsic heteroatomic nature of the FeCoN 6 sites provides a stepped energy landscape for optimized Na + capture‐release pathways. This synergy between electronic OMCD modulation and the kinetic capture‐release model significantly lowers the diffusion barrier. Consequently, the FeCo dual‐atom nitrogen‐doped carbon anode exhibits dominant pseudocapacitive kinetics, superior rate capability (225 mAh g −1 at 10 A g −1 ), and exceptional durability. The full SHC delivers a high energy density of 165 Wh kg −1 at 23 W kg −1 , retains 108 Wh kg −1 at 9424 W kg −1 , and achieves 90% capacity retention over 10,000 cycles. This study establishes that engineering heteroatomic sites to leverage both intrinsic functional heterogeneity and electronic delocalization is a powerful strategy to overcome kinetic limitations in energy storage.

Donor–Acceptor Engineering Enables Kinetic Control of Chirality Transfer in Side Chain Polymers

ABSTRACT Chirality transfer across hierarchical architectures represents a pivotal and underexplored challenge in the design of functional chiral materials. Through molecular engineering integrating chiral α ‐terminal groups with electronically tunable azobenzene (Azo) side chains, we demonstrate that in kinetically trapped aggregates of side chain Azo polymers, the dipole moment of the chromophore, modulated by terminal electron‐donating (Donor, D) or withdrawing (Acceptor, A) substituents, dictates the absolute inversion of the resulting supramolecular helix. The substituent‐dependent dipole reorientation cascades into long‐range helical reorganization via π‐π and van der Waals cooperativity, ultimately governing whether chirality transfer follows thermodynamic preference, undergoes inversion, or exhibits multiplexed behavior. This electronically driven chirality inversion transcends classical steric models and establishes a transformative framework for designing adaptive chiral materials with programmable handedness, offering promising applications in photonic circuits, enantioselective nanosensors, and bioinspired metamaterials.

Tailoring Hydrogenation Pathway to Redirect CO ₂ Electroreduction From Ethylene to Ethanol

ABSTRACT Electrochemical CO 2 reduction to ethanol faces a fundamental challenge: competing ethylene formation through shared C 2 intermediates. While previous studies focused on modifying catalyst electronic structures or increasing *CO coverage, the critical role of competitive hydrogenation pathways remains unexplored. Here, we demonstrate that the selectivity between ethanol and ethylene is governed by the balance between Langmuir–Hinshelwood (surface *H) and Eley–Rideal (solvent H) hydrogenation mechanisms. Through hierarchically assembled BPEI/PT interfaces, we dynamically modulate this balance by reconstructing interfacial hydrogen‐bond networks without altering catalyst electronic properties. In situ Raman spectroscopy captures enhanced *OCHCH 2 /*OCHCH 3 intermediates, directly correlating ethanol selectivity with suppressed ER pathway. Combined experimental and theoretical studies establish quantitative relationships between hydrogen‐bond strength and pathway selectivity. This strategy achieves 38.7% ethanol Faradaic efficiency (FE) at 900 mA cm − 2 on CuO‐derived catalysts (116% improvement) and 53% at 800 mA cm − 2 on CuAg systems—among the highest reported efficiencies. Our findings reveal that controlling competitive hydrogenation pathways through interfacial engineering provides an independent parameter for steering CO 2 reduction selectivity.

Tri(Thiophene‐Nitrile) Covalent Organic Frameworks With Low HOMO/LUMO Donor/Acceptor for High‐Potential‐Plateau Zinc Batteries

ABSTRACT Covalent organic frameworks (COFs) featuring desirable redox‐active sites have become competitive cathode materials for aqueous zinc‐organic batteries (ZOBs). However, multi‐active COFs, albeit with high capacity, are often confined to their sloping and low redox potential (<0.8 V) caused by high molecular orbital energy levels (HOMO/LUMO) of active moieties. Here we report a capacity‐voltage trade‐off‐breaking design of COFs by pairing low‐HOMO trithiophene donor (−6.04 eV) with low‐LUMO trinitrile acceptor (−3.82 eV) via robust olefin linkages (TN‐COF), using high‐LUMO triazine acceptor (−1.75 eV) as the counterpart (TA‐COF). The tri(thiophene‐nitrile) donor‐acceptor enables low HOMO/LUMO energy levels (−3.98/−5.94 eV) for TN‐COF cathode, thus unlocking a flat and high redox potential of 1.2 V compared to TA‐COF (0.9 V). An 18‐electron CF 3 SO 3 − /NH 4 + (de)coordination process is activated per hexagonal tri(thiophene‐nitrile) unit in TN‐COF cathode with ultralow activation energy (0.17 eV). This facilitates 98.2% utilization of C−S/C≡N active sites to liberate high capacity of 335 mAh g −1 (vs. 80.1%/268 mAh g −1 for TA‐COF). The ideal combination of high voltage and capacity gives TN‐COF cathode superior energy density (402 Wh kg −1 ) and ultralong life (70,000 cycles). This finding widens the design philosophy of high‐voltage‐capacity COFs via HOMO/LUMO energy engineering for advanced ZOBs.

Recyclable Thermoset Enabled by Copolymer of Elemental Sulfur and Acrylate With Controlled Disulfide Linkages

ABSTRACT Thermoset polymers have found a number of applications. However, their recycling faces a challenge due to their chemically crosslinked structure, which brings environmental pollution. Introduction of dynamic disulfide linkages can overcome this obstacle in principle. Yet, the disulfide compounds used to build the dynamic bonds are very limited and expensive, making their practical applications rather difficult. In this study, we present copolymer of elemental sulfur (S 8 ) and acrylate with controlled disulfide linkages synthesized via anionic hybrid copolymerization (AHCP). Such a copolymer can serve as a curing agent for conventional thermosetting resins including epoxy, polyurethane, and unsaturated polyester. The resulting thermoset demonstrates remarkable reprocessability, retaining over 86% of its maximum stress and strain at break after five cycles of processing at 120°C and pressure of 10 MPa. It also exhibits strong UV‐blocking capability with zero transmittance in the ultraviolet range. Particularly, the thermoset is recyclable. Namely, it can degrade into oligomers in the presence of S 8 , which can be reused as curing agents for new thermosets or directly employed as robust adhesives for diverse substrates. The precise synthesis of polymer with controlled disulfide linkages provides a platform to transform conventional thermosets into high‐performance recyclable materials.

Outside Back Cover: Dynamic Spin Governing Asymmetric Coordination Fields in Trimetallic Single‐Atom Catalysts for Optimal Oxygen Reduction (Angew. Chem. Int. Ed. 12/2026)

Coumarin‐30 Enables Site‐Resolved Detection of Tubulin Ligands by Microscale Thermophoresis

Abstract Tubulins are among the most successful targets for cancer chemotherapy. However, the emergence of drug resistance stimulates the continuous search for novel chemotherapeutics. We discovered that coumarin‐30, a widely available laser dye, binds to the colchicine site of tubulin, inhibiting microtubule dynamics and cancer cell division at submicromolar concentrations. Exploiting the excellent fluorescent properties of coumarin‐30, we developed a fast, accurate, and cost‐effective coumarin‐30‐based microscale thermophoresis (C‐MST) assay as an express method for detecting tubulin–ligand interactions and discriminating colchicine site binders from ligands targeting other protein pockets. Using this assay, we identified several potent tubulin polymerization inhibitors associating with the colchicine site and validated them through in vitro microtubule dynamics and cell cycle assays in cancer cells. Furthermore, the C‐MST assay was demonstrated to detect ligands targeting a novel binding site on tubulin, recently established through crystallographic fragment screening. We confirmed detection of a small‐molecule ligand targeting that site and further designed and characterized a series of its analogs. The ability of the C‐MST assay to detect tubulin binders regardless of their binding site or their effect on microtubule dynamics opens new avenues for developing unconventional modulators of tubulin–tubulin and tubulin–effector interactions thereby facilitating anticancer drug discovery.

Crown Ether Rotaxane‐Induced Construction of COF Membranes With Recognition Channels for High‐Efficiency Ion Sieving

ABSTRACT Biological ion channels can achieve high ion discrimination through the synergy between pore structure and microenvironment. However, constructing biomimetic ion‐sieving membranes with precise recognition capabilities for target ions remains challenging. Herein, we propose a rotaxane‐induced stacking method for constructing COF membranes integrated with ion‐recognition sub‐nanoscale channels. The dibenzo‐crown ether rotaxane COF (CRCOF) nanosheets are fabricated and subsequently stacked into membranes. Driven by π–π interactions between rotaxane moieties and CRCOF nanosheets, as well as the specific ion‐recognition ability of rotaxanes, the nanosheets undergo oriented stacking, yielding well‐defined sub‐nanoscale channels equipped with recognition sites. The angstrom‐scale pore size and specific binding channels synergistically enhance selectivity and minimize transport energy penalties of target ions. By modulating the ion recognition capability of channels, the obtained CRCOF membrane demonstrates an exceptional Li + permeation rate of 0.04 mol m −2 h −1 (approximately five times higher than reported polymer membranes) and high Li + selectivity (Li + /Mg 2+ selectivity of 315 and Li + /Na + selectivity of 12) in a mixture solution. This work provides a new avenue for the accurate construction of biomimetic ion‐sieving membranes and offers new insights into the mechanisms of high‐efficiency ion separation in sub‐nanoscale confined recognition channels.