Abstract
Na-ion cathode materials operating at high voltage with a stable cycling behavior are needed to develop future high-energy Na-ion cells. However, the irreversible oxygen redox reaction at ...the high-voltage region in sodium layered cathode materials generates structural instability and poor capacity retention upon cycling. Here, we report a doping strategy by incorporating light-weight boron into the cathode active material lattice to decrease the irreversible oxygen oxidation at high voltages (i.e., >4.0 V vs. Na
+
/Na). The presence of covalent B–O bonds and the negative charges of the oxygen atoms ensures a robust ligand framework for the NaLi
1/9
Ni
2/9
Fe
2/9
Mn
4/9
O
2
cathode material while mitigating the excessive oxidation of oxygen for charge compensation and avoiding irreversible structural changes during cell operation. The B-doped cathode material promotes reversible transition metal redox reaction enabling a room-temperature capacity of 160.5 mAh g
−1
at 25 mA g
−1
and capacity retention of 82.8% after 200 cycles at 250 mA g
−1
. A 71.28 mAh single-coated lab-scale Na-ion pouch cell comprising a pre-sodiated hard carbon-based anode and B-doped cathode material is also reported as proof of concept.
Covalent organic frameworks (COFs) are a class of organic crystalline porous materials discovered in the early 21st century that have become an attractive class of emerging materials due to their ...high crystallinity, intrinsic porosity, structural regularity, diverse functionality, design flexibility, and outstanding stability. However, many chemical and physical properties strongly depend on the presence of metal ions in materials for advanced applications, but metal-free COFs do not have these properties and are therefore excluded from such applications. Metalated COFs formed by combining COFs with metal ions, while retaining the advantages of COFs, have additional intriguing properties and applications, and have attracted considerable attention over the past decade. This review presents all aspects of metalated COFs, from synthetic strategies to various applications, in the hope of promoting the continued development of this young field.
This review highlights the recent advances of metalated covalent organic frameworks, including synthetic strategies and applications, and discusses the current challenges and future directions.
As one of the most promising cathodes for rechargeable sodium‐ion batteries (SIBs), O3‐type layered transition metal oxides commonly suffer from inevitably complicated phase transitions and sluggish ...kinetics. Here, a NaLi0.05Ni0.3Mn0.5Cu0.1Mg0.05O2 cathode material with the exposed {010} active facets by multiple‐layer oriented stacking nanosheets is presented. Owing to reasonable geometrical structure design and chemical substitution, the electrode delivers outstanding rate performance (71.8 mAh g−1 and 16.9 kW kg−1 at 50C), remarkable cycling stability (91.9% capacity retention after 600 cycles at 5C), and excellent compatibility with hard carbon anode. Based on the combined analyses of cyclic voltammograms, ex situ X‐ray absorption spectroscopy, and operando X‐ray diffraction, the reaction mechanisms behind the superior electrochemical performance are clearly articulated. Surprisingly, Ni2+/Ni3+ and Cu2+/Cu3+ redox couples are simultaneously involved in the charge compensation with a highly reversible O3–P3 phase transition during charge/discharge process and the Na+ storage is governed by a capacitive mechanism via quantitative kinetics analysis. This optimal bifunctional regulation strategy may offer new insights into the rational design of high‐performance cathode materials for SIBs.
An O3‐type NaLi0.05Ni0.3Mn0.5Cu0.1Mg0.05O2 cathode material with exposed {010} active facets by multiple‐layer oriented stacking nanosheets is successfully constructed via reasonable structure design and chemical substitution. An optimal bifunctional regulation is demonstrated to be an efficient strategy to restrain the unfavorable multiphase transformation and greatly improve Na+ transport kinetics resulting in excellent performance for sodium‐ion batteries.
As newly emerged crystalline porous materials, covalent organic frameworks (COFs) possess fascinating structures and some specific features such as modularity, crystallinity, porosity, stability, ...versatility, and biocompatibility. Besides adsorption/separation, sensing, catalysis, and energy applications, COFs have recently shown a promise in biomedical applications. This contribution provides an overview of the recent developments of COF‐based medicines in cancer therapeutics, including drug delivery, photodynamic therapy (PDT), photothermal therapy (PTT), and combined therapy. Furthermore, the major challenges and developing trends in this field are also discussed. These recent developments are summarized and discussed to help encourage further contributions in this emerging and promising field.
Magic bullet: In this minireview, recent advances in the field of covalent organic frameworks (COFs) for cancer therapeutic applications are highlighted, including those for drug delivery, phototherapy, and combined therapy.
Ca2+, a ubiquitous but nuanced modulator of cellular physiology, is meticulously controlled intracellularly. However, intracellular Ca2+ regulation, such as mitochondrial Ca2+ buffering capacity, can ...be disrupted by 1O2. Thus, the intracellular Ca2+ overload, which is recognized as one of the important cell pro‐death factors, can be logically achieved by the synergism of 1O2 with exogenous Ca2+ delivery. Reported herein is a nanoscale covalent organic framework (NCOF)‐based nanoagent, namely CaCO3@COF‐BODIPY‐2I@GAG (4), which is embedded with CaCO3 nanoparticle (NP) and surface‐decorated with BODIPY‐2I as photosensitizer (PS) and glycosaminoglycan (GAG) targeting agent for CD44 receptors on digestive tract tumor cells. Under illumination, the light‐triggered 1O2 not only kills the tumor cells directly, but also leads to their mitochondrial dysfunction and Ca2+ overload. An enhanced antitumor efficiency is achieved via photodynamic therapy (PDT) and Ca2+ overload synergistic therapy.
A multifunctional COF‐based nanoagent, which is equipped with BODIPY‐2I photosensitizer, CaCO3 nanoparticle, and glycosaminoglycan (GAG) targeting agent, can be a highly efficient and selective antitumor nanomedicine for colon tumor via photodynamic therapy (PDT) and Ca2+ overload synergistic therapy.
Chemodynamic therapy (CDT), which induces cell death by decomposing high levels of H2O2 in tumor cells into highly toxic ·OH, is recognized as a promising antineoplastic approach. However, current ...CDT approaches are often restricted by the highly controlled and upregulated cellular antioxidant defense. To enhance ·OH‐induced cellular damage by CDT, a covalent organic framework (COF)‐based, ferrocene (Fc)‐ and glutathione peroxidase 4 (GPX4) inhibitor‐loaded nanodrug, RSL3@COF–Fc (2b), is fabricated. The obtained 2b not only promotes in situ Fenton‐like reactions to trigger ·OH production in cells, but also attenuates the repair mechanisms under oxidative stress via irreversible covalent GPX4 inhibition. As a result, these two approaches synergistically result in massive lipid peroxide accumulation, subsequent cell damage, and ultimately ferroptosis, while not being limited by intracellular glutathione. It is believed that this research provides a paradigm for enhancing reactive oxygen species‐mediated oncotherapy through redox dyshomeostasis and may provide new insights for developing COF‐based nanomedicine.
Versatile covalent organic frameworks (COFs)! The organic nanodrug RSL3@COF–Fc (2b), which integrates the glutathione peroxidase 4 inhibitor RSL3 and Fenton‐like reaction catalyst ferrocene (Fc) into a nanoscale COF, induces ferroptosis to enhance chemodynamic therapy by blocking lipid repair and disrupting cellular redox homeostasis.
Covalent organic frameworks (COFs), as a new emerging class of highly crystalline advanced porous materials with fascinating structural tunability and diversity as well as the desired semiconductor ...properties, have gained significant attention as highly promising and efficient photocatalysts or designer platforms for a variety of photocatalytic applications in recent years; thus a comprehensive review is timely to summarize the advances of this field. In this review, a background and brief timeline concerning the developments and key achievements of COFs are provided. Afterwards, a systematic overview of the potential photocatalytic applications realized to date in the fast growing field of COFs is provided with the aim of presenting a full blueprint of COFs for possible photochemical energy conversion and reactions. Finally, the challenges remaining and personal perspectives on further development of this type of material for photocatalysis are presented.
In this review, a comprehensive summary of the potential photocatalytic applications realized to date in the fast-growing field of COFs is provided with the aim to present a full blueprint of COFs for photochemical energy conversion and reactions.
A general and efficient organocatalytic asymmetric polymerization approach for the synthesis of chiral covalent organic frameworks (CCOFs) has been developed. With a chiral 2‐methylpyrrolidine ...catalyst, a series of tris(N‐salicylideneamine)‐derived β‐ketoenamine‐CCOFs are directly constructed from prochiral aldehyde‐ and primary amine‐monomers. The adopted aminocatalytic asymmetric Schiff‐base condensation herein is performed under ambient conditions with clear green synthetic advantages over the conventional acid‐catalysed solvothermal methods. The obtained β‐ketoenamine‐CCOFs can be further metalated by a solid‐state coordination approach, and the resulting CuII@CCOFs can highly promote an asymmetric A3‐coupling reaction. Specifically, a CuII@CCOF@chitosan aerogel was fabricated as a highly efficient fixed‐bed model reactor for scaled‐up catalysis. The concept of aminocatalytic asymmetric polymerization might open a new way for constructing the CCOFs via asymmetric organocatalysis.
A new and general organocatalytic asymmetric polymerization approach for the chiral covalent organic framework (CCOF) synthesis under ambient conditions is presented. The metalated CCOF can be further shaped into a fixed‐bed reactor by incorporation with ecofriendly and low‐cost chitosan to realize the scaled‐up catalytic asymmetric A3‐coupling reaction in a green and facile way.
Low‐cost and stable sodium‐layered oxides (such as P2‐ and O3‐phases) are suggested as highly promising cathode materials for Na‐ion batteries (NIBs). Biphasic hybridization, mainly involving P2/O3 ...and P2/P3 biphases, is typically used to boost their electrochemical performances. Herein, a P3/O3 intergrown layered oxide (Na2/3Ni1/3Mn1/3Ti1/3O2) as high‐rate and long‐life cathode for NIBs via tuning the amounts of Ti substitution in Na2/3Ni1/3Mn2/3−xTixO2 (x = 0, 1/6, 1/3, 2/3) is demonstrated. The X‐ray diffraction (XRD) Rietveld refinement and aberration‐corrected scanning transmission electron microscopy show the co‐existence of P3 and O3 phases, and density functional theory calculation corroborates the appearance of the anomalous O3 phase at the Ti substitution amount of 1/3. The P3/O3 biphasic cathode delivers an unexpected rate capability (≈88.7% of the initial capacity at a high rate of 5 C) and cycling stability (≈68.7% capacity retention after 2000 cycles at 1 C), superior to those of the sing phases P3‐Na2/3Ni1/3Mn2/3O2, P3‐Na2/3Ni1/3Mn1/2Ti1/6O2, and O3‐Na2/3Ni1/3Ti2/3O2. The highly reversible structural evolution of the P3/O3 integrated cathode observed by ex situ XRD, ex situ X‐ray absorption spectra, and the rapid Na+ diffusion kinetics, underpin the enhancement. These results show the important role of P3/O3 biphasic hybridization in designing and engineering layered oxide cathodes for NIBs.
P3/O3 biphasic Na2/3Ni1/3Mn1/3Ti1/3O2 cathode material is prepared for Na‐ion batteries by tuning the Ti amounts. This P3/O3 intergrown cathode delivers superior rate capability and cycling stability to those of the pristine P3 and O3 phases, which are underpinned by the observed highly reversible structural transition of P3/O3 biphase and the rapid Na+ diffusion kinetics.
For seeking high enantiopurity, the previously reported thermal asymmetric catalysis is usually carried out at low temperature sometimes with limited yield, that is, the high enantiomeric excess (ee) ...usually at the cost of high yield. Thus, the achieving both high stereoselectivity and yield is an enormous challenge. We report herein two metal nanoparticle (M NP)-loaded and porphyrin-containing homochiral covalent organic framework (CCOF)-based composite catalysts, and their application in the thermally-driven asymmetric one-pot Henry and A
-coupling reactions. All the reactions are conducted at elevated temperatures with both excellent stereoselectivity and yield which resulted from the synergy of CCOF confinement effect and M NP catalytic activation. Notably, the needed thermal energy for the asymmetric reactions herein is derived from the photothermal conversion via porphyrin-based CCOF upon irradiation with visible light. Remarkably, the CCOF confinement effect can be effectively maintained up to 100 °C for the asymmetric one-pot Henry and A
-coupling reactions herein.
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