Hydrogen-bonded organic framework modified separator for simultaneously enhancing the safety and electrochemical performance of Ni-rich lithium-ion battery

Nickel-rich layered oxide cathode(LiNi_(x)Co_(y)Mn_(1−x−y)O_(2),x>0.5,NCM)shows substantial potential for applications in longer-range electrical vehicles.However,the rapid capacity decay and serious safety concerns impede its practical viability.This work provides a hydrogen-bonded organic framework(HOF)modification strategy to simultaneously improve the electrochemical performance,thermal stability and incombustibility of separator.Melamine cyanurate(MCA),as a low-cost and reliable flame-retardant HOF,was implemented in the separator modification layer,which can prevent the battery short circuit even at a high temperature.In addition,the supermolecule properties of MCA provide unique physical and chemical microenvironment for regulating ion-transport behavior in electrolyte.The MCA coating layer enabled the nickel-rich layered oxide cathode with a high-capacity retention of 90.3%after 300 cycles at 1.0 C.Collectively,the usage of MCA in lithium-ion batteries(LIBs)affords a simple,low-cost and efficient strategy to improve the security and service life of nickel-rich layered cathodes.

High-throughput mechanistic study of highly selective hydrogen-bonded organic frameworks for electrochemical nitrate reduction to ammonia

Hydrogen-bonded organic frameworks(HOFs),an emerging porous macrocyclic materials linked by hydrogen-bond,hold potential for gas separation and storage,sensors,optical,and electrocatalysts.Here,HOF-based electrocatalysts are rationally developed for nitrates reduction to ammonia,allowing not only to regulate wastewater pollution but also to accomplish carbon-neutral ammonia(NH_(3))synthesis.We preform high-throughput computational screening of thirty-six HOFs with various metals as active sites,denoted as HOF-M1,for nitrate reduction reaction(NO_(3)RR)toward NH_(3).We have implemented a hierarchical four-step screening strategy,and ultimately,HOF-Ti1 was selected based on its exceptional catalytic activity and selectivity in the NO_(3)RR process.Through additional analysis,we discovered that the d band center of the active metal sites serves as an effective parameter for designing and predicting the performance of HOFs in NO_(3)RR.This research not only showcases the immense potential of electrocatalysis in transforming NO_(3)RR into NH_(3)but also provides researchers with a compelling incentive to undertake further experimental investigations.

A Novel Porphyrin-based Hydrogen-bonded Organic Framework

A novel hydrogen-bonded organic framework, HOF-TCPP(HOF = hydrogen bonded organic framework, TCPP = tetrakis(4-carboxyphenyl) porphyrin), has been synthesized via solvothermal reaction in ethylene glycol. Crystal structure was well determined by single-crystal X-ray diffraction and powder X-ray diffraction(PXRD). Topological analysis reveals that HOF-TCPP exhibits sql 2D layer and features 2D → 3D polycatenation. Fluorescence investigation shows that HOF-TCPP displays much higher photoluminescence(PL) intensity than the amorphous ligands TCPP, which can be ascribed to the crystalline structure and hydrogen bonds existing in the structure.

Hydrogen-bonded organic framework-ionic liquid composite quasisolid electrolyte for high-performance lithium battery

Ionic liquids(ILs)hold great promise as highperformance electrolyte material due to their unique advantages including nonvolatility,high thermal stability and high ionic conductivity.However,the IL-based electrolytes always suffer from serious ion aggregation and high viscosity at low temperatures,leading to significantly decline in ionic conductivity.Here,hydrogen-bonded organic framework-ionic liquid composite quasi-solid electrolyte(high temperature treatment(HT)-HOF-IL CQSE)was prepared through confining the IL electrolytes(ILEs)into the pore of HOF lamellar framework.The weak hydrogen bonding interactions within HOF nanosheets,together with the generated interactions between ILE and HOF,enable uniform and continuous distribution of ILE in HOF lamellar framework.This effectively inhibits the ion migration of ILE,which meanwhile serves as Li+transfer sites,affording high ionic conductivity of 5.7×10^(-5)S·cm-1 at-60 ℃,with high lithium-ion transference number of 0.69,whereas ILEs usually lose ionic conduction ability at such low temperatures.The assembled Li symmetrical cell can stably cycle at 0.2 mA·cm^(-2)and^(-2)0 ℃ for more than 1500 h.The LiFePO_(4)|HT-HOF-IL CQSE|Li cell shows excellent cycling performance at 0.5 C at a wide temperature range of^(-2)0 to 60 ℃.This work may pave a new avenue for the development of high-performance IL-based composite electrolytes.

A hydrogen-bonded organic framework containing fluorescent carbazole and responsive pyridyl units for sensing organic acids

Hydrogen-bonded organic frameworks(HOFs)are a promising candidate for optical sensing,but the lack of effective design strategies poses significant challenges to the construction of HOFs for organic acid sensing.In this work,the first HOF for organic acid sensing is reported by constructing a multiplepyridine carbazole-based dense HOF,namely HOF-FJU-206,from a tripyridine-carbazole molecular 3,6-bis(pyridin-4-yl)-9-(4-(pyridin-4-yl)phenyl)-9H-carbazole(CPPY)with carbazole center for luminescence,pyridyl sites for its responsive of hydrogen proton,and narrow channels in the dense framework for the diffusion of hydrogen protons.HOF-FJU-206 exhibits differential responsively fluorescence sensing and recovery properties to formic,acetic,and propionic acids with different molecular sizes and p Kavalue(acid dissociation constant).The dissociation degree of various acids can be determined by analyzing the slope of changes in both peak wavelength and intensity of in-situ fluorescence,which easily enables the dual-corrective recognition of different acids.The varying degree of protonation at pyridine sites is proved to be the reason for differential sensing of various acids,as demonstrated by1H NMR spectra,X-ray photoelectron spectroscopy(XPS)characterization,and modeling studies.

Stable hydrogen-bonded organic frameworks and their photo-and electro-responses

Hydrogen-bonded organic frameworks(HOFs)are a recent class of porous materials that have garnered considerable research interest owing to their distinctive characteristics.HOFs can be constructed through judicious selection of H-bonding motifs,which are further enforced by other weak intermolecular interactions such asπ–πstacking,van der Waals forces,and framework interpenetration.Taking advantage of these interactions,we can expand the functional field of HOFs by introducing active molecules.Recently,researchers have made substantial advancements in using HOFs for chemical sensing,catalysis,proton conduction,biological applications,and others.The low bonding energy of H-bonds allows for precise control over the concentration of ligands in solvents,forming diverse HOF structures.These varied structures offer significant advantages for producing HOFs with photo-responsive and electro-responsive properties.However,the presence of H-bonds in HOFs results in their inherent lower stability compared to metal-organic frameworks(MOFs)and covalent-organic frameworks(COFs)formed via coordination and covalent bonds,respectively.As a result,the pursuit of stable and innovative HOF materials with novel functional sites remains an ongoing challenge.This review provides an overview of recent research progress in the development of new strategies for stable HOF synthesis and applications of HOFs with stimuli-responsive properties.We first classified all synthetic methods reported to date and discussed the stable HOFs synthesized,as well as their unique properties and applications.In addition,we summarized the applications of HOFs utilizing their synergistic responses to external stimuli,including photo,electrical,pressure,and chemical stimuli.We systematically reviewed stable HOF synthesis and applications,which may lead to a deeper understanding of the structure–activity relationship for these materials and guide future HOF design.

Hydrogen-bonded organic framework core–shell composite for synergistic antimicrobial therapy

Hydrogen-bonded organic frameworks(HOFs)are crystalline porous materials with permanent voids formed via self-assembly of organic molecules through hydrogen bonding and intermolecular forces.Further combination of HOFs with functional material would broaden their application horizon but were less explored in existing literature.Herein,a highly porous and photosensitive HOF was successfully coated onto upconversion nanoparticles(UCNPs)to construct a core-shell structure named UNCPs@PFC-73-Ni.To enhance spectral overlap and maximize energy conversion efficiency,this study utilized the Er and Tm co-doped UCNPs,which can effectively convert infrared light into visible light emission thereby exciting the porphyrin shell.Subsequent investigation reveals that the composite exhibits significant photodynamic and photothermal effects under infrared light.Encouraged by its noticeable photoactivity,UCNPs@PFC-73-Ni was evaluated as an antibacterial agent against Escherichia coli.Notably,significant antibacterial efficacy was observed,highlighting the potential of UCNPs@PFC-73-Ni as an effective antibacterial agent under infrared light irradiation.

Sticked-Layer Strategy to a Flexible-Robust Hydrogen-Bonded Organic Framework for Efficient C_(2)H_(2)/CO_(2)Separation

Flexible-robust hydrogen-bonded organic frameworks(HOFs)are attracting increasing interest due to their excellent separation performance for important industrial gases,but the construction remains challenging.Herein,a sticked-layer strategy is first proposed to construct a flexible-robust HOF,HOFFJU-8,from a donor(D)–π–acceptor(A)molecule 4,4′,4″,4‴-(pyrrolo[3,2-b]pyrrole-1,2,4,5-tetrayl)tetrabenzonitrile(DP-4CN).HOF-FJU-8 is amicroporous three-dimensional framework composed of two kinds of DP-4CN molecules,one acting as building units for the two-dimensional layer via C≡N···H–C hydrogen bond dimers and another as the sticks to link the layers along channels through D–Aπ···πinteractions.The activated framework HOF-FJU-8a possesses flexible-robust pore characteristics,as determined by the gas adsorption and in situ gas-loaded powder X-ray diffraction.HOF-FJU-8a exhibits adaptive adsorption and stronger binding affinity to C_(2)H_(2)rather than CO_(2)due to the flexible-robust nature,which can effectively separate acetylene and carbon dioxide mixtures.

Synthesis, Crystal Structure and Characterization of a New Hydrogen-bonded Organic Framework

The hydrogen-bonded organic framework(PFC-32),constructed by tetrahydroxyquinone(THQN)and diethylamine(DEA),was readily prepared via hydrothermal synthesis in DEF(N,N-diethylformamide).PFC-32 was characterized by PXRD,IR,UV-Vis,TGA and photoluminescence(PL).Single crystal analysis reveals that PFC-32 shows a three-dimensional(3 D)framework,where the THQN anions are coplanar and separated by DEA cations.PFC-32 displays intrinsic photoluminescence property owing to the alleviation of the aggregation-caused quenching(ACQ)effect caused byπ-πstacking.

Amidinium sulfonate hydrogen-bonded organic framework with fluorescence amplification function for sensitive aniline detection

Although the construction of specific functional crystalline materials is still challenging,the multi-component molecular assembly has become a key solution for the design of functional materials.Here,we report a hydrogen-bonded organic framework(HOF)material FJU-360 constructed from disodium 6‑hydroxy-5-[(4-sulfophenyl)azo]-2-naphthalenesulfonate(SSY)and terephthalimidamide.The charge-assisted hydrogen bonding between amidinium and sulfonate makes FJU-360 produce much stronger fluorescence than SSY,and can be used as a luminescence sensor to rapidly quench aniline through luminescence quenching.FJU-360 is sensitive and highly selective for the detection of aniline,and the detection limit reached 3.2 nmol/L,which is the lowest value reported currently.The mechanism of aniline response was analyzed through the aniline@FJU-360 single crystal structure,and the luminescence mechanism was clarified through density function theory calculations.This work is an important step towards the rational synthesis and assembly of sensing materials.

Two-in-one tecton strategy to construct single crystalline hydrogen-bonded organic framework with high proton conductivity above 100℃

By tactically integrating two different kinds of proton donors and acceptors into one supramolecular tecton, a new crystalline hydrogen-bonded organic framework(HOF-SXU-1) has been developed. HOF-SXU-1 features a remarkable proton conductivity as high as 6.32 mS cm^(-1) and an extremely low activation energy of 0.16 eV at 160℃ under anhydrous N_(2) conditions.By contrast, under identical conditions, the organic precursors of HOF-SXU-1 only exhibit negligible proton conduction performance, demonstrating that the formation of HOF is crucial for excellent proton conduction performance.

Robust Hydrogen-Bonded Organic Framework with Four-Fold Interpenetration for Adsorptive Separation of C_(2)H_(6)/C_(2)H_(4) and Xe/Kr

Hydrogen-bonded organic frameworks(HOFs)are an emerging class of porous materials that hold promise for the adsorptive separation of industrially relevant gas mixtures.However,developing HOFs with high thermal stability and resistance to water remains a daunting challenge.We report here a microporous HOF(HIAM-103)assembled from a hexacarboxylate linker(2,4,6-trimethylbenzene-1,3,5-triylisophthalic acid,H6TMBTI).The compound crystallizes in the trigonal crystal system,and its structure is a four-fold interpenetrated network.Upon thermal activation,the single crystals remain intact,allowing for precise determination of the activated structure.HIAM-103 exhibits remarkable thermal and hydrothermal stability.Its microporous channels demonstrate selective adsorption of C_(2)H_(6)over C_(2)H_(4)and Xe over Kr,and its separation capability toward mixed gases has been validated by column breakthrough experiments under dry and humid conditions.The preferential gas adsorption sites and separation mechanisms have been uncovered through DFT analysis,which suggests that the methyl group decorated 1D channels are the primary reason for the selective adsorption.

Topochemical polymerization of hydrogen-bonded organic framework for supporting ultrafine palladium nanoparticles

Topochemical polymerization of molecular crystals into porous materials is of significance due to their promising applications in the field of adsorption and catalysis,yet rarely reported due to the synthesis difficulty.Herein,a hydrogen-bonded organic framework(HOF-45)has been fabricated by the crystallization of a cage-like building block containing three alkynyl groups.It exhibits almost mesoporous structure demonstrated by single crystal X-ray diffraction study.Light-driven topochemical polymerization of HOF-45 with ethanedithiol covalently links alkynyl groups in HOF-45,generating a hydrogen-bond and covalentbond cross-linked material(HOF-45C).In contrast to HOF-45,cross-linked HOF-45C retains the crystalline nature and displays improved solution resistence according to the powder X-ray diffraction data.In particular,HOF-45C is able to support the growth of ultrafine palladium nanoparticles with the average size of ca.1.9 nm for rapidly promoting the degradation of nitrophenol,methyl orange,and congo red with the help of NaBH_(4)as well as Suzuki-Miyaura coupling reaction.This work inputs a new idea on the HOFs application in preparing covalent-linked porous organic materials.

Information encryption with a high information-carrying capacity based on a stimulus-responsive hydrogen-bonded organic framework and a smartphone

Information-carrying capacity has become an important factor in the development of encryption and anti-counterfeiting.Herein,a hydrogen-bonded organic framework(HOF-PyTTA)was developed as novel anti-counterfeiting ink without rare metals and a smartphone-based APP was written for encryption and anti-counterfeiting.We found that the fluorescence of HOF-PyTTA can be quenched by Fe^(3+)ions and recovered by the addition of ascorbic acid.And the fluorescence of HOF-PyTTA can be enhanced by the increasing concentrations of ethanol.Based on these stimulus-response properties,four anti-counterfeiting models with gradually increased security were studied.Mode one was printed by HOFs ink and decrypted by UV light.Mode two was based on HOF-PyTTA and CsPbBr_(3)inks(or HOF-PyTTA-Fe^(3+))which are used to separately print the genuine and pirated information.A decryption reagent was applied to get the genuine information.Furthermore,we successfully construct a dynamic information encryption anti-counterfeiting model using a fluorescence array in combination with an information encryption anticounterfeiting APP.The circular array is printed by several concentrations of HOF-PyTTA ink and different RGB thresholds are set with the help of the information encryption anti-counterfeiting APP,to obtain distinct encrypted anti-counterfeiting information,thus accomplishing a high information-carrying capacity.

Hydrogen-bonded organic framework for red light-mediated photocatalysis

The development of heterogeneous molecule-based catalysts for red light-mediated photocatalysis is still challenging due to the improper light absorption for most materials and the photoactivity deactivation for solid assembly.Herein,red light photocatalysis with a hydrogen-bonded organic framework(HOF)is established.This HOF,named HOF-66,is formed from the self-assembly of guanine-decorated naphthalenediimide(NDI)molecule through hydrogen-bonded guanine-quadruplex nodes,showing square grid supramolecular layers confirmed by powder X-ray diffraction analysis.In contrast to unsubstituted NDI HOF,introduction of ethylamino groups to NDI core in HOF-66 tunes strong electronic maximum absorption peak to 619 nm,allowing red light photocatalysis of singlet oxygen evolution proved by 1,3-diphenylisobenzofuran degradation and electron spin resonance determination.Particularly,under the same conditions,the sulfide oxidation rate in the presence of HOF-66 was 28 times higher compared to its unsubstituted analogue.This work integrates the molecular design and aggregation effect towards the application of HOFs,opening a new gate for red light photocatalysts.

Dual-functional hydrogen-bonded organic frameworks for aniline and ultraviolet sensitive detection

A novel hydrogen-bonded organic frameworks(HOFs)FJU-200 has been constructed from N,N’-bis(5-isophthalic acid)naphthalimide(H_(4)L).FJU-200 has a good dual-function of aniline and ultraviolet detection.FJU-200 is the first case of HOF with dual sensing of visual color changes and photoluminescence quenching for aniline detection,and the detection limit of aniline can reach5.5 x 10^(-4)mol/L.Under ultraviolet FJU-200 will rapidly change from light yellow to rustic brown,which makes it possible to use FJU-200 to achieve minute-level ultraviolet detection.Moreover,for more convenient use,FJU-200 test papers are prepared.Using them,convenient and fast aniline or ultraviolet detection can be realized.The single-crystal X-ray structures show that compared with the original FJU-200,both PhNH_(2)@FJU-200 and UV-FJU-200 have larger pore sizes,and the dihedral angles of the H_(2)L^(2-)in framework has been changed.

Superprotonic Conductivity of Guanidinium Organosulfonate Hydrogen-Bonded Organic Frameworks with Nanotube-Shaped Proton Transport Channels

Grasping proton transport pathways and mecha-nisms is vital for the application of fuel cell technology.Herein,we screened four guanidinium organosulfonate charge-assisted hydro-gen-bonded organic frameworks(HOFs),namely,GBBS,G3TSPHB,G4TSP,and G6HSPB,which possess high hydrogen-bonded density proton transport networks shaped like nanotubes.These materials were prepared by self-assembly through charge-assisted interactions between guanidinium cations and organo-sulfonate anions,as well as by host-guest regulation.At 80℃ and 93%RH,the proton conductivity of GBBS,G3TSPHB,G4TSP,and G6HSPB can reach 4.56×10^(-2),2.55×10^(-2),4.01×10^(-2),and 10^(-1) cm^(-1),Doping G6HSPB into the Nafion matrix prepared composite membranes for testing the performance of fuel cells.At 80°C and 98%RH,the proton conductivity of 9%-G6HSPB@Nafion reached a maximum value of 1.14×10^(-1) S cm^(-1),which is 2.8 times higher than recast Nafion.The results showed that charge-assisted HOFs with high proton channel density have better proton transport properties,providing a reference for the design of highly proton-conducting materials.

Achieving Bright Mechanoluminescence in a Hydrogen-Bonded Organic Framework by Polar Molecular Rotor Incorporation

Luminescent hydrogen-bonded organic frameworks(HOFs)have attracted increasing attention due to their corresponding luminescence that enables readily visualization of structural dynamics.HOFs with the mechanoluminescence(ML)property can emit light without photon excitation and are greatly attractive for advanced applications,but research in this area has been limiting.Herein,we report the first example of an ML-active flexible HOF with permanent porosity,named 8PCOM,assembled from polar molecular rotors with an aggregation-induced emission property.When responding to different solvent vapors,reversible structural transformations between ML-active and-inactive 8PCOM frameworks occur,including a single-crystal-to-single-crystal(SCSC)transformation.Thus,guest-induced breathing behaviors are mainly attributed to phenyl rotations of polar molecular rotors induced by external stimuli.During reversible structural transformations of various 8PCOM frameworks with different pores,the significant ML property is achieved successfully through supramolecular dipole moment regulation.Upon mechanical force,bright emission of the ML-active 8PCOM framework is observed without UV irradiation,and the ML-active crystals can be easily prepared and regenerated.This work not only provides a valuable strategy for engineering future multifunctional HOFs but also enriches the types and applications of existing luminescent porous materials.

All‑Covalent Organic Framework Nanofilms Assembled Lithium‑Ion Capacitor to Solve the Imbalanced Charge Storage Kinetics

Free-standing covalent organic framework(COFs)nanofilms exhibit a remarkable ability to rapidly intercalate/de-intercalate Li^(+) in lithium-ion batteries,while simultaneously exposing affluent active sites in supercapacitors.The development of these nanofilms offers a promising solution to address the persistent challenge of imbalanced charge storage kinetics between battery-type anode and capacitor-type cathode in lithium-ion capacitors(LICs).Herein,for the first time,custom-made COFBTMB-TP and COFTAPB-BPY nanofilms are synthesized as the anode and cathode,respectively,for an all-COF nanofilm-structured LIC.The COFBTMB-TP nanofilm with strong electronegative–CF3 groups enables tuning the partial electron cloud density for Li^(+) migration to ensure the rapid anode kinetic process.The thickness-regulated cathodic COFTAPB-BPY nanofilm can fit the anodic COF nanofilm in the capacity.Due to the aligned 1D channel,2D aromatic skeleton and accessible active sites of COF nanofilms,the whole COFTAPB-BPY//COFBTMB-TP LIC demonstrates a high energy density of 318 mWh cm^(−3) at a high-power density of 6 W cm^(−3),excellent rate capability,good cycle stability with the capacity retention rate of 77%after 5000-cycle.The COFTAPB-BPY//COFBTMB-TP LIC represents a new benchmark for currently reported film-type LICs and even film-type supercapacitors.After being comprehensively explored via ex situ XPS,7Li solid-state NMR analyses,and DFT calculation,it is found that the COFBTMB-TP nanofilm facilitates the reversible conversion of semi-ionic to ionic C–F bonds during lithium storage.COFBTMB-TP exhibits a strong interaction with Li^(+) due to the C–F,C=O,and C–N bonds,facilitating Li^(+) desolation and absorption from the electrolyte.This work addresses the challenge of imbalanced charge storage kinetics and capacity between the anode and cathode and also pave the way for future miniaturized and wearable LIC devices.

Challenges and Opportunities in Preserving Key Structural Features of 3D-Printed Metal/Covalent Organic Framework

Metal-organic framework(MOF)and covalent organic framework(COF)are a huge group of advanced porous materials exhibiting attractive and tunable microstructural features,such as large surface area,tunable pore size,and functional surfaces,which have significant values in various application areas.The emerging 3D printing technology further provides MOF and COFs(M/COFs)with higher designability of their macrostructure and demonstrates large achievements in their performance by shaping them into advanced 3D monoliths.However,the currently available 3D printing M/COFs strategy faces a major challenge of severe destruction of M/COFs’microstructural features,both during and after 3D printing.It is envisioned that preserving the microstructure of M/COFs in the 3D-printed monolith will bring a great improvement to the related applications.In this overview,the 3D-printed M/COFs are categorized into M/COF-mixed monoliths and M/COF-covered monoliths.Their differences in the properties,applications,and current research states are discussed.The up-to-date advancements in paste/scaffold composition and printing/covering methods to preserve the superior M/COF microstructure during 3D printing are further discussed for the two types of 3D-printed M/COF.Throughout the analysis of the current states of 3D-printed M/COFs,the expected future research direction to achieve a highly preserved microstructure in the 3D monolith is proposed.