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1.
Small ; : e2402255, 2024 Jun 05.
Artigo em Inglês | MEDLINE | ID: mdl-38837847

RESUMO

The application of electrically conductive 1D coordination polymers (1D CPs) in nanoelectronic molecular recognition is theoretically promising yet rarely explored due to the challenges in their synthesis and optimization of electrical properties. In this regard, two tetrathiafulvalene-based 1D CPs, namely [Co(m-H2TTFTB)(DMF)2(H2O)]n (Co-m-TTFTB), and {[Ni(m-H2TTFTB)(CH3CH2OH)1.5(H2O)1.5]·(H2O)0.5}n (Ni-m-TTFTB) are successfully constructed. The shorter S···S contacts between the [M(solvent)3(m-H2TTFTB)]n chains contribute to a significant improvement in their electrical conductivities. The powder X-ray diffraction (PXRD) under different organic solvents reveals the flexible and dynamic structural characteristic of M-m-TTFTB, which, combined with the 1D morphology, lead to their excellent performance for sensitive detection of volatile organic compounds. Co-m-TTFTB achieves a limit of detection for ethanol vapor down to 0.5 ppm, which is superior to the state-of-the-art chemiresistive sensors based on metal-organic frameworks or organic polymers at room temperature. In situ diffuse reflectance infrared Fourier transform spectroscopy, PXRD measurements and density functional theory calculations reveal the molecular insertion sensing mechanism and the corresponding structure-function relationship. This work expands the applicable scenario of 1D CPs and opens a new realm of 1D CP-based nanoelectronic sensors for highly sensitive room temperature gas detection.

2.
Acc Chem Res ; 2024 Jun 20.
Artigo em Inglês | MEDLINE | ID: mdl-38902854

RESUMO

ConspectusThe directed synthesis and functionalization of porous crystalline materials pose significant challenges for chemists. The synergistic integration of different functionalities within an ordered molecular material holds great significance for expanding its applications as functional materials. The presence of coordination bonds connected by inorganic and organic components in molecular materials can not only increase the structural diversity of materials but also modulate the electronic structure and band gap, which further regulates the physical and chemical properties of molecular materials. In fact, porous crystalline materials with coordination bonds, which inherit the merits of both organic and inorganic materials, already showcase their superior advantages in optical, electrical, and magnetic applications. In addition to the inorganic components that provide structural rigidity, organic ligands of various types serve as crucial connectors in the construction of functional porous crystalline materials. In addition, redox activity can endow organic linkers with electrochemical activity, thereby making them a perfect platform for the study of charge transfer with atom-resolved single-crystal structures, and they can additionally serve as stimuli-responsive sites in sensor devices and smart materials.In this Account, we introduce the synthesis, structural characteristics, and applications of porous crystalline materials based on the famous redox-active units, tetrathiafulvalene (TTF) and its analogues, by primarily focusing on metal-organic frameworks (MOFs) and covalent organic frameworks (COFs). TTF, a sulfur-rich conjugated molecule with two reversible and easily accessible oxidation states (i.e., radical TTF•+ cation and TTF2+ dication), and its analogues boast special electrical characteristics that enable them to display switchable redox activity and stimuli-responsive properties. These inherent properties contribute to the enhancement of the optical, electrical, and magnetic characteristics of the resultant porous crystalline materials. Moreover, delving into the charge transfer phenomena, which is key for the electrochemical process within these materials, uncovers a myriad of potential functional applications. The Account is organized into five main sections that correspond to the different properties and applications of these materials: optical, electrical, and magnetic functionalities; energy storage and conversion; and catalysis. Each section provides detailed discussions of synthetic methods, structural characteristics, the physical and chemical properties, and the functional performances of highlighted examples. The Account also discusses future directions by emphasizing the exploration of novel organic units, the transformation between radical cation TTF•+ and dication TTF2+, and the integration of multifunctionalities within these frameworks to foster the development of smart materials for enhanced performance across diverse applications. Through this Account, we aim to highlight the massive potential of TTF and its analogues-based porous crystals in chemistry and material science.

3.
Angew Chem Int Ed Engl ; : e202407277, 2024 May 23.
Artigo em Inglês | MEDLINE | ID: mdl-38780892

RESUMO

Chiral multi-resonance thermally activated delayed fluorescence (CP-MR-TADF) materials hold promise for circularly polarized organic light-emitting diode (CP-OLED) and 3D display. Herein, we present two pairs of tetraborated intrinsically axial CP-MR-TADF materials, R/S-BDBF-BOH and R/S-BDBT-BOH, with conjugation-extended bidibenzo[b,d]furan and bidibenzo[b,d]thiophene as chiral sources, which effectively participate in the distribution of frontier molecular orbitals. Due to the heavy-atom effect, sulfur atoms are introduced to accelerate the reverse intersystem crossing process and increase efficiency of molecules. R/S-BDBF-BOH and R/S-BDBT-BOH manifest ultra-pure blue emission peaking at 458/459 nm with full width at half maximum of 27 nm (0.16 eV), photoluminescence quantum yields of 90%/91% and dissymmetry factors (|gPL|) of 6.8 × 10-4/8.5 × 10-4, respectively. Correspondingly, the CP-OLEDs exhibit good performances with external quantum efficiency of 30.1% and |gEL| factors of 1.2 × 10-3.

4.
Chem Commun (Camb) ; 60(45): 5812-5815, 2024 May 30.
Artigo em Inglês | MEDLINE | ID: mdl-38747473

RESUMO

A stable two-dimensional radical hydrogen-bonded metal-organic framework, constructed using a modified tetrathiafulvalene-tetrabenzoate ((2-Me)-H4TTFTB) linker and Cd2+ ions, exhibits a high electrical conductivity of 4.1 × 10-4 S m-1 and excellent photothermal conversion with a temperature increase of 137 °C in 15 s under the irradiation of a 0.7 W cm-2 808 nm laser.

5.
Small Methods ; : e2301705, 2024 Mar 26.
Artigo em Inglês | MEDLINE | ID: mdl-38530062

RESUMO

Polymer materials formed by conventional metal-ligand bonds have very low branch functionality, the crosslinker of such polymer usually consists of 2-4 polymer chains and a single metal ion. Thus, these materials are weak, soft, humidity-sensitive, and unable to withstand their shape under long-term service. In this work, a new hyperbranched metal-organic cluster (MOC) crosslinker containing up to 16 vinyl groups is prepared by a straightforward coordination reaction. Compared with the current typical synthesis of metal-organic cages (MOCs) or metal-organic-polyhedra (MOP) crosslinkers with complex operations and low yield, the preparation of the MOC is simple and gram-scale. Thus, MOC can serve as a high-connectivity crosslinker to construct hyper-crosslinked polymer networks. The as-prepared elastomer exhibits mechanical robustness, creep-resistance, and humidity-stability. Besides, the elastomer possesses self-healing and recyclability at mild condition as well as fluorescence stability. These impressive comprehensive properties are proven to originate from the hyper-crosslinked topological structure and microphase-separated morphology. The MOC-driven hyper-crosslinked elastomers provide a new solution for the construction of mechanically robust, durable, and multifunctional polymers.

6.
J Am Chem Soc ; 146(13): 9385-9394, 2024 Apr 03.
Artigo em Inglês | MEDLINE | ID: mdl-38512124

RESUMO

The shuttling of polysulfides on the cathode and the uncontrollable growth of lithium dendrites on the anode have restricted the practical application of lithium-sulfur (Li-S) batteries. In this study, a metal-coordinated 3D covalent organic framework (COF) with a homogeneous distribution of nickel-bis(dithiolene) and N-rich triazine centers (namely, NiS4-TAPT) was designed and synthesized, which can serve as bifunctional hosts for both sulfur cathodes and lithium anodes in Li-S batteries. The abundant Ni centers and N-sites in NiS4-TAPT can greatly enhance the adsorption and conversion of the polysulfides. Meanwhile, the presence of Ni-bis(dithiolene) centers enables uniform Li nucleation at the Li anode, thereby suppressing the growth of Li dendrites. This work demonstrated the effectiveness of integrating catalytic and adsorption sites to optimize the chemical interactions between host materials and redox-active intermediates, potentially facilitating the rational design of metal-coordinated COF materials for high-performance secondary batteries.

7.
Angew Chem Int Ed Engl ; 63(17): e202400758, 2024 Apr 22.
Artigo em Inglês | MEDLINE | ID: mdl-38450854

RESUMO

Designing materials capable of adapting their mechanical properties in response to external stimuli is the key to preventing failure and extending their service life. However, existing mechanically adaptive polymers are hindered by limitations such as inadequate load-bearing capacity, difficulty in achieving reversible changes, high cost, and a lack of multiple responsiveness. Herein, we address these challenges using dynamic coordination bonds. A new type of mechanically adaptive material with both rate- and temperature-responsiveness was developed. Owing to the stimuli-responsiveness of the coordination equilibria, the prepared polymers, PBMBD-Fe and PBMBD-Co, exhibit mechanically adaptive properties, including temperature-sensitive strength modulation and rate-dependent impact hardening. Benefitting from the dynamic nature of the coordination bonds, the polymers exhibited impressive energy dissipation, damping capacity (loss factors of 1.15 and 2.09 at 1.0 Hz), self-healing, and 3D printing abilities, offering durable and customizable impact resistance and protective performance. The development of impact-resistant materials with comprehensive properties has potential applications in the sustainable and intelligent protection fields.

8.
Small ; 20(14): e2308013, 2024 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-37988642

RESUMO

Redox-active tetrathiafulvalene (TTF)-based covalent organic frameworks (COFs) exhibit distinctive electrochemical and photoelectrical properties, but their prevalent two-dimensional (2D) structure with densely packed TTF moieties limits the accessibility of redox center and constrains their potential applications. To overcome this challenge, an 8-connected TTF linker (TTF-8CHO) is designed as a new building block for the construction of three-dimensional (3D) COFs. This approach led to the successful synthesis of a 3D COF with the bcu topology, designated as TTF-8CHO-COF. In comparison to its 2D counterpart employing a 4-connected TTF linker, the 3D COF design enhances access to redox sites, facilitating controlled oxidation by I2 or Au3+ to tune physical properties. When irradiated with a 0.7 W cm-2 808 nm laser, the oxidized 3D COF samples ( I X - ${\mathrm{I}}_{\mathrm{X}}^{-}$ @TTF-8CHO-COF and Au NPs@TTF-8CHO-COF) demonstrated rapid temperature increases of 239.3 and 146.1 °C, respectively, which surpassed those of pristine 3D COF (65.6 °C) and the 2D COF counterpart (6.4 °C increment after I2 treatment). Furthermore, the oxidation of the 3D COF heightened its photoelectrical responsiveness under 808 nm laser irradiation. This augmentation in photothermal and photoelectrical response can be attributed to the higher concentration of TTF·+ radicals generated through the oxidation of well-exposed TTF moieties.

9.
Angew Chem Int Ed Engl ; 62(27): e202305246, 2023 Jul 03.
Artigo em Inglês | MEDLINE | ID: mdl-37158129

RESUMO

Nitrate-containing industrial wastewater poses a serious threat to the global food security and public health safety. As compared to the traditional microbial denitrification, electrocatalytic nitrate reduction shows better sustainability with ultrahigh energy efficiency and the production of high-value ammonia (NH3 ). However, nitrate-containing wastewater from most industrial processes, such as mining, metallurgy, and petrochemical engineering, is generally acidic, which contradicts the typical neutral/alkaline working conditions for both denitrifying bacteria and the state-of-the-art inorganic electrocatalysts, leading to the demand for pre-neutralization and the problematic hydrogen evaluation reaction (HER) competition and catalyst dissolution. Here, we report a series of Fe2 M (M=Fe, Co, Ni, Zn) trinuclear cluster metal-organic frameworks (MOFs) that enable the highly efficient electrocatalytic nitrate reduction to ammonium under strong acidic conditions with excellent stability. In pH=1 electrolyte, the Fe2 Co-MOF demonstrates the NH3 yield rate of 20653.5 µg h-1 mg-1 site with 90.55 % NH3 -Faradaic efficiency (FE), 98.5 % NH3 -selectivity and up to 75 hr of electrocatalytic stability. Additionally, successful nitrate reduction in high-acidic conditions directly produce the ammonium sulfate as nitrogen fertilizer, avoiding the subsequent aqueous ammonia extraction and preventing the ammonia spillage loss. This series of cluster-based MOF structures provide new insights into the design principles of high-performance nitrate reduction catalysts under environmentally-relevant wastewater conditions.

10.
Angew Chem Int Ed Engl ; 62(27): e202304183, 2023 Jul 03.
Artigo em Inglês | MEDLINE | ID: mdl-37154674

RESUMO

Modulation of the ligands and coordination environment of metal-organic frameworks (MOFs) has been an effective and relatively unexplored avenue for improving the anode performance of lithium-ion batteries (LIBs). In this study, three MOFs are synthesized, namely, M4 (o-TTFOB)(bpm)2 (H2 O)2 (where M is Mn, Zn, and Cd; o-H8 TTFOB is ortho-tetrathiafulvalene octabenzoate; and bpm is 2,2'-bipyrimidine), based on a new ligand o-H8 TTFOB with two adjacent carboxylates on one phenyl, which allows us to establish the impact of metal coordination on the performance of these MOFs as anode materials in LIBs. Mn-o-TTFOB and Zn-o-TTFOB, with two more uncoordinated oxygen atoms from o-TTFOB8- , show higher reversible specific capacities of 1249 mAh g-1 and 1288 mAh g-1 under 200 mA g-1 after full activation. In contrast, Cd-o-TTFOB shows a reversible capacity of 448 mAh g-1 under the same condition due to the lack of uncoordinated oxygen atoms. Crystal structure analysis, cyclic voltammetry measurements of the half-cell configurations, and density functional theory calculations have been performed to explain the lithium storage mechanism, diffusion kinetics, and structure-function relationship. This study demonstrates the advantages of MOFs with high designability in the fabrication of LIBs.

11.
Chemistry ; 29(34): e202301048, 2023 Jun 19.
Artigo em Inglês | MEDLINE | ID: mdl-37022345

RESUMO

Tetrathiafulvalene (TTF) and Ni-bis(dithiolene) are typical conductive units widely studied in electronics, optics, and photochemistry. However, their applications in near-infrared (NIR) photothermal conversion are often limited by insufficient NIR absorption and low chemical/thermal stability. Herein, we integrate TTF and Ni-bis(dithiolene) into a covalent organic framework (COF) with stable and efficient NIR and solar photothermal conversion performance. Two isostructural COFs, namely Ni-TTF and TTF-TTF, are successfully isolated which are composed of TTF and Ni-bis(dithiolene) units as donor-acceptor (D-A) pairs or TTF units only. Both COFs show high BET surface areas and good chemical/thermal stability. Notably, compared with TTF-TTF, the periodic D-A arrangement in Ni-TTF significantly lowers the bandgap, leading to unprecedented NIR and solar photothermal conversion performance.

12.
J Am Chem Soc ; 145(18): 10227-10235, 2023 May 10.
Artigo em Inglês | MEDLINE | ID: mdl-37074687

RESUMO

Stable metal-organic frameworks (MOFs) with mesopores (2-50 nm) are promising platforms for immobilizing nanosized functional compounds, such as metal-oxo clusters, metal-sulfide quantum dots, and coordination complexes. However, these species easily decompose under acidic conditions or high temperatures, hindering their in situ encapsulation in stable MOFs, which are usually synthesized under harsh conditions involving excess acid modulators and high temperatures. Herein, we report a route for the room-temperature and acid-modulator-free synthesis of stable mesoporous MOFs and MOF catalysts with acid-sensitive species encapsulated: (1) we initially construct a MOF template by connecting stable Zr6 clusters with labile Cu-bipyridyl moieties; (2) Cu-bipyridyl moieties are subsequently exchanged by organic linkers to afford a stable version of Zr-MOFs; (3) acid-sensitive species, including polyoxometalates (POMs), CdSeS/ZnS quantum dots, and Cu-coordination cages, can be encapsulated in situ into the MOFs during step 1. The room-temperature synthesis allows the isolation of mesoporous MOFs with 8-connected Zr6 clusters and reo topology as kinetic products, which are inaccessible by traditional solvothermal synthesis. Furthermore, acid-sensitive species remain stable, active, and locked within the frameworks during MOF synthesis. We observed high catalytic activity for VX degradation by the POM@Zr-MOF catalysts as a result of the synergy between redox-active POMs and Lewis-acidic Zr sites. The dynamic bond-directed method will accelerate the discovery of large-pore stable MOFs and offer a mild route to avoid the decomposition of catalysts during MOF synthesis.

13.
Angew Chem Int Ed Engl ; 62(22): e202301993, 2023 May 22.
Artigo em Inglês | MEDLINE | ID: mdl-36995342

RESUMO

Room-temperature phosphorescence (RTP) polymers, whose emission can persist for a long period after photoexcitation, are of great importance for practical applications. Herein, dynamic covalent boronic ester linkages with internal B-N coordination are incorporated into a commercial epoxy matrix. The reversible dissociation of B-N bonds upon loading provides an efficient energy dissipation pathway for the epoxy network, while the rigid epoxy matrix can inhibit the quenching of triplet excitons in boronic esters. The obtained polymers exhibit enhanced mechanical toughness (12.26 MJ m-3 ), ultralong RTP (τ=540.4 ms), and shape memory behavior. Notably, there is no apparent decrease in the RTP property upon prolonged immersion in various solvents because the networks are robust. Moreover, the dynamic bonds endow the polymers with superior reprocessablity and recyclability. These novel properties have led to their potential application for information encryption and anti-counterfeiting.

14.
Sci Adv ; 9(5): eadf2398, 2023 Feb 03.
Artigo em Inglês | MEDLINE | ID: mdl-36724229

RESUMO

The rational design of efficient and stable catalysts for the oxygen reduction reaction and oxygen evolution reaction (ORR/OER) is the key to improving Li-O2 battery performance. Here, we report the construction of ORR/OER bifunctional cathode catalysts in a covalent organic framework (COF) platform by simultaneously incorporating Ni-bis(dithiolene) and Co-porphyrin units. The resulting bimetallic Ni/Co-COF exhibits high surface area, fairly good electrical conductivity, and excellent chemical stability. Li-O2 batteries with the Ni/Co-COF-based cathode show a low discharge/charge potential gap (1.0 V) and stable cycling (200 cycles) at a current density of 500 mA g-1, rivaling that of PtAu nanocrystals. Density functional theory computations and control experiments using nonmetal or single metal-based isostructural COFs reveal the critical role of Ni and Co sites in reducing the discharge/charge overpotentials and regulating the Li2O2 deposition. This work highlights the advantage of bimetallic COFs in the rational design of efficient and stable Li-O2 batteries.

15.
Angew Chem Int Ed Engl ; 62(10): e202211850, 2023 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-36636786

RESUMO

Metal-organic frameworks (MOFs), with diverse metal nodes and designable organic linkers, offer unique opportunities for the rational engineering of semiconducting properties. In this work, we report a mixed-linker conductive MOF system with both tetrathiafulvalene and Ni-bis(dithiolene) moieties, which allows the fine-tuning of electronic structures and semiconductive characteristics. By continuously increasing the molar ratio between tetrathiafulvalene and Ni-bis(dithiolene), the switching of the semiconducting behaviors from n-type to p-type was observed along with an increase in electrical conductivity by 3 orders of magnitude (from 2.88×10-7  S m-1 to 9.26×10-5  S m-1 ). Furthermore, mixed-linker MOFs were applied for the chemiresistive detection of volatile organic compounds (VOCs), where the sensing performance was modulated by the corresponding linker ratios, showing synergistic and nonlinear modulation effects.

16.
Angew Chem Int Ed Engl ; 62(6): e202217045, 2023 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-36517419

RESUMO

Chiral boron/nitrogen doped multiple resonance thermally activated delayed fluorescence (MR-TADF) emitters are promising for highly efficient and color-pure circularly polarized organic light-emitting diodes (CP-OLEDs). Herein, we report two pairs of MR-TADF materials (Czp-tBuCzB, Czp-POAB) based on planar chiral paracyclophane with photoluminescence quantum yields of up to 98 %. The enantiomers showed symmetric circularly polarized photoluminescence spectra with dissymmetry factors |gPL | of up to 1.6×10-3 in doped films. Meanwhile, the sky-blue CP-OLEDs with (R/S)-Czp-tBuCzB showed an external quantum efficiency of 32.1 % with the narrowest full-width at half-maximum of 24 nm among the reported CP-OLEDs, while the devices with (R/S)-Czp-POAB displayed the first nearly pure green CP electroluminescence with |gEL | factors at the 10-3 level. These results demonstrate the incorporation of planar chirality into MR-TADF emitter is a reliable strategy for constructing of efficient CP-OLEDs.

17.
Nat Chem ; 15(2): 286-293, 2023 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-36522581

RESUMO

The design of highly electron-active and stable heterogeneous catalysts for the ambient nitrogen reduction reaction is challenging due to the inertness of the N2 molecule. Here, we report the synthesis of a zinc-based coordination polymer that features bridging dinitrogen anionic ligands, {[Zn(L)(N2)0.5(TCNQ-TCNQ)0.5]·(TCNQ)0.5}n (L is tetra(isoquinolin-6-yl)tetrathiafulvalene and TCNQ is tetracyanoquinodimethane), and show that it is an efficient photocatalyst for nitrogen fixation under an ambient atmosphere. It exhibits an ammonia conversion rate of 140 µmol g-1 h-1 and functions well also with unpurified air as the feeding gas. Experimental and theoretical studies show that the active [Zn2+-(N≡N)--Zn2+] sites can promote the formation of NH3 and the detachment of the NH3 formed creates unsaturated [Zn2+···Zn+] intermediates, which in turn can be refilled by external N2 sequestration and fast intermolecular electron migration. The [Zn2+···Zn+] intermediates stabilized by the sandwiched cage-like donor-acceptor-donor framework can sustain continuous catalytic cycles. This work presents an example of a molecular active site embedded within a coordination polymer for nitrogen fixation under mild conditions.

18.
Angew Chem Int Ed Engl ; 61(41): e202209984, 2022 Oct 10.
Artigo em Inglês | MEDLINE | ID: mdl-35981975

RESUMO

Herein, we report two multiple-resonance thermally activated delayed fluorescence emitters (VTCzBN and TCz-VTCzBN) based on indolo[3,2,1-jk]carbazole unit and boron-nitrogen skeletons, whose emissions peaking at 496 and 521 nm with full width at half maximum of 34 and 29 nm, respectively. Meanwhile, fast rate constants of reverse intersystem crossing of above 106  s-1 are obtained due to small singlet-triplet energy gaps and large spin-orbital coupling values. Notably, planar molecular structures along the transition dipole moment direction endow them with high horizontal emitting dipole ratios of up to 94 %. Consequently, the corresponding organic light-emitting diodes (OLEDs) show the maximum external quantum efficiencies of 31.7 % and 32.2 %, respectively. Particularly, OLED with TCz-VTCzBN display ultra-pure green emission with Commission Internationale de l'Eclairage coordinates of (0.22, 0.71), consistent with the green display standard of the National Television System Committee.

19.
Adv Mater ; 34(36): e2204253, 2022 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-35839149

RESUMO

The realization of luminescent materials with narrowband and circularly polarized luminescence (CPL) is of great significance for the development of future optical and photonic devices. Herein, through a steric-hindrance-assisted dual-core strategy, two pairs of chiral dual-core multiple resonance thermally activated delayed fluorescence (MR-TADF) materials (R/S-DOBN and R/S-DOBNT) are directly constructed by the bonding of two organoboron MR-TADF monocores (SOBN and SOBNT) with carbazole/3,6-di-tert-butyl-9H-carbazole and phenol derivative as donors, realizing obvious CPL and narrowband emissions. Furthermore, the dual-core effect in the prepared R/S-DOBN and R/S-DOBNT increases the transition oscillator strength two times more than that of a monocore structure, while maintaining the ultrapure blue emissions peaking at 453 and 459 nm with a narrower full-width at half-maximum of 21 nm through reorganization energy reduction. The circularly polarized organic light-emitting diodes based on the enantiomers exhibit ultrapure blue emission with Commission Internationale de L'Eclairage (CIE) coordinates of (0.14, 0.10) and (0.13, 0.12), high maximum external quantum efficiencies of 23.9% and 25.6%, and obvious circularly polarized electroluminescence with dissymmetry factors (|gEL |) ≈ 10-3 .

20.
J Am Chem Soc ; 144(18): 8267-8277, 2022 May 11.
Artigo em Inglês | MEDLINE | ID: mdl-35484687

RESUMO

Combining the chemistry of metal-organic frameworks (MOFs) and covalent organic frameworks (COFs) can bring new opportunities for the design of advanced materials with enhanced tunability and functionality. Herein, we constructed two COFs based on Ni-bis(dithiolene) units and imine bonds, representing a bridge between traditional MOFs and COFs. The Ni-bis(dithiolene)tetrabenzaldehyde as the 4-connected linker was initially synthesized, which was further linked by 4-connected tetra(aminophenyl)pyrene (TAP) or 3-connected tris(aminophenyl)amine (TAA) linkers into two COFs, namely, Ni-TAP and Ni-TAA. Ni-TAP shows a two-dimensional sql network, while TAA is a twofold interpenetrated framework with an ffc topology. They both exhibit a high Brunauer-Emmett-Teller surface area (324 and 689 m2 g-1 for Ni-TAP and Ni-TAA, respectively), a fairly good conductivity (1.57 × 10-6 and 9.75 × 10-5 S m-1 for Ni-TAP and Ni-TAA, respectively), and high chemical stability (a stable pH window of 1-14 for Ni-TAA). When applied in lithium metal batteries as an intermediate layer for guiding the uniform Li electrodeposition, Ni-TAP and Ni-TAA displayed impressive lithiophilicity and high Li-ion conductivity, enabling the achievement of smooth and dense Li deposition with a clear columnar morphology and stable Li plating/stripping behaviors with high Li utilization, which is anticipated to pave the way to upgrade Li metal anodes for application in high-energy-density battery systems.

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