We report a new method to promote the conductivities of metal–organic frameworks (MOFs) by 5 to 7 magnitudes, thus their potential in electrochemical applications can be fully revealed. This method ...combines the polarity and porosity advantages of MOFs with the conductive feature of conductive polymers, in this case, polypyrrole (ppy), to construct ppy‐MOF compartments for the confinement of sulfur in Li–S batteries. The performances of these ppy‐S‐in‐MOF electrodes exceed those of their MOF and ppy counterparts, especially at high charge–discharge rates. For the first time, the critical role of ion diffusion to the high rate performance was elucidated by comparing ppy‐MOF compartments with different pore geometries. The ppy‐S‐in‐PCN‐224 electrode with cross‐linked pores and tunnels stood out, with a high capacity of 670 and 440 mAh g−1 at 10.0 C after 200 and 1000 cycles, respectively, representing a new benchmark for long‐cycle performance at high rate in Li–S batteries.
MOF host S: The electrical conductivity of metal–organic frameworks (MOFs) was promoted by the construction of polymer–MOF composites. Using MOF‐based sulfur hosts, the critical role of porosity at high charge–discharge rates in Li–S batteries was elucidated. MOFs with short ion transfer pathways and large pore apertures were identified as the most suitable for long‐term cycling at extremely high rates.
Chitosan is a naturally originating product that can be applied in many areas due to its biocompatibility, biodegradability, and nontoxic properties. The broad-spectrum antimicrobial activity of ...chitosan offers great commercial potential for this product. Nevertheless, the antimicrobial activity of chitosan varies, because this activity is associated with its physicochemical characteristics and depends on the type of microorganism. In this review article, the fundamental properties, modes of antimicrobial action, and antimicrobial effects-related factors of chitosan are discussed. We further summarize how microorganisms genetically respond to chitosan. Finally, applications of chitosan-based biomaterials, such as nanoparticles and films, in combination with current clinical antibiotics or antifungal drugs, are also addressed.
Electrocatalytic carbon dioxide reduction reaction (CO2RR) to produce ethylene (C2H4) is conducive to sustainable development of energy and environment. At present, most electrocatalysts for C2H4 ...production are limited to the heavy metal copper, meanwhile, achieving metal‐free catalysis remains a challenge. Noted piperazine with sp3 N hybridization is beneficial to CO2 capture, but CO2RR performance and mechanism have been lacking. Herein, based on linkage engineering, we construct a novel high‐density sp3 N catalytic array via introducing piperazine into the crystalline and microporous aminal‐linked covalent organic frameworks (COFs). Thanks to its high sp3 N density, strong CO2 capture capacity and great hydrophilicity, aminal‐linked COF successfully achieves the conversion of CO2 to C2H4 with a Faraday efficiency up to 19.1 %, which is stand out in all reported metal‐free COF electrocatalysts. In addition, a series of imine‐linked COFs are synthesized and combined with DFT calculations to demonstrate the critical role of sp3 N in enhancing the kinetics of CO2RR. Therefore, this work reveals the extraordinary potential of linkage engineering in COFs to break through some catalytic bottlenecks.
Metal‐free covalent organic frameworks (COFs) are constructed by linkage engineering to efficiently catalyze the carbon dioxide reduction reaction (CO2RR). The catalytic array structure composed of sp3 N sites in the aminal linkages promotes CO2 capture and enhances the reaction kinetics for C2H4 production, thus showing a much higher Faraday efficiency of C2H4 than imine‐linked COFs.
Vascular restenosis after balloon dilation is largely caused by the over‐proliferation of smooth muscle cells, which is triggered and exacerbated by local excessive inflammation and oxidative stress. ...The excessive inflammatory and oxidative stress cause tissue/cell damage, hamper endothelial functions, and worsen intimal hyperplasia and restenosis. A high level of reactive oxygen species (ROS) overproduction is regarded as the main culprit. Therefore, efficiently inhibiting ROS over‐production or weightily depleting them is of great significance. Herein, a “ROS‐responsive/scavenging prodrug” is introduced into balloon coating for the treatment of vascular restenosis. A reversible phenylboronic ester‐bearing caffeic acid (CA) macromolecular prodrug (PBC) is designed for the controlled and on‐demand dual‐drug release triggered by the local high ROS level; the released CA and 4‐hydroxybenzyl alcohol exhibit efficient antioxidant and anti‐inflammatory effects by scavenging ROS, thereby regulating vascular microenvironment and protecting endothelium functions. To accelerate endothelium regeneration, pro‐endothelial microRNA‐126 is further introduced. The ROS‐responsive/scavenging prodrug/miRNA balloon coating efficiently prevents intimal hyperplasia, alleviates local inflammation, and improves endothelium healing in a rat abdominal aorta restenosis model, which may provide applicative perspectives for next‐generation drug‐coated balloons and other cardiovascular diseases treatment.
A reversible phenylboronic ester‐bearing caffeic acid (CA) macromolecular prodrug (PBC) is designed for the controlled and on‐demand dual‐antioxidant release (CA and 4‐hydroxybenzyl alcohol (HBA)) triggered by the local high reactive oxygen species (ROS) level, thereby exhibiting antioxidant and anti‐inflammatory effects; the pro‐endothelial microRNA‐126 is introduced to further accelerate endothelialization. This ROS‐responsive/scavenging prodrug/miRNA balloon coating efficiently inhibits long‐term vascular restenosis.
Porous materials have been widely used in batteries and supercapacitors attribute to their large internal surface area (usually 100–1000m2g−1) and porosity that can favor the electrochemical ...reaction, interfacial charge transport, and provide short diffusion paths for ions. As a new type of porous crystalline materials, metal-organic frameworks (MOFs) have received huge attention in the past decade due to their unique properties, i.e. huge surface area (up to 7000m2g−1), high porosity, low density, controllable structure and tunable pore size. A wide range of applications including gas separation, storage, catalysis, and drug delivery benefit from the recent fast development of MOFs. However, their potential in electrochemical energy storage has not been fully revealed. Herein, the present mini review appraises recent and significant development of MOFs and MOF-derived materials for rechargeable lithium ion batteries and supercapacitors, to give a glimpse into these potential applications of MOFs.
MOFs with large surface area and high porosity can offer more reaction sites and charge carriers diffusion path. Thus MOFs are used as cathode, anode, electrolyte, matrix and precursor materials for lithium ion battery, and also as electrode and precursor materials for supercapacitors. Display omitted
•MOFs have potential in electrochemical area due to their high porosity and diversity.•We summarized and compared works on MOFs for lithium ion battery and supercapacitor.•We pointed out critical challenges and provided possible solutions for future study.
A cathode for high‐rate performance lithium‐ion batteries (LIBs) has been developed from a crystal habit‐tuned nanoplate Li(Li0.17Ni0.25Mn0.58)O2 material, in which the proportion of (010) nanoplates ...(see figure) has been significantly increased. The results demonstrate that the fraction of the surface that is electrochemically active for Li+ transportation is a key criterion for evaluating the different nanostructures of potential LIB materials.
The lithium–sulfur battery is considered to be one of the most promising rechargeable energy storage systems because of its high theoretical energy density. Unfortunately, the shuttle effect during ...cycling causes serious loss of sulfur species and corrosion of the lithium metal anode, resulting in severe capacity decay. This work proposes to completely suppress the shuttle effect of lithium polysulfides (LiPSs) without sacrificing the interfacial Li+ transport, through in situ construction of a compact cathode electrolyte interphase (CEI), which is formed of the reaction between vinylene carbonate (VC), bis(trifluoromethane)sulfonimide ions and LiPSs in a self‐limiting manner during the initial discharge process. Hence, the CEI‐confined sulfur cathode in the VC‐based electrolyte with a solid phase conversion mechanism delivers a long‐term cycling stability and high‐rate performance, as well as excellent performance under an extreme climate in a subzero temperature of −20 °C, limited lithium source with a low N/P ratio of 1.1, and even at mechanical mutilation. The present study reveals an appealing approach to tailor the composition and interfacial structure of sulfur cathodes by in situ construction of a robust, self‐healing, and high Li+ conductive CEI from the aspect of electrolyte, and thus completely solve the issue of the shuttle effect.
A favorable cathode electrolyte interphase (CEI) design is realized for sulfur electrodes by the fast reaction between vinylene carbonate, bis(trifluoromethane)sulfonimide ions, and lithium polysulfides during the initial discharge process. This strategy leads to the in situ formation of a robust, thin, and self‐healing CEI without sacrificing interfacial Li+ transport. Thus, the CEI‐confined sulfur cathodes perform well under high‐rate, long‐cycle stability, low N/P ratio, and subzero temperature.
Silicon-based materials are promising candidates for anodes of rechargeable lithium-ion batteries due to their high theoretical capacities and natural abundance. However, the large volume changes ...during discharge-charge processes, results in structural degradation and serious specific capacity decay. Compared to the over-emphasized efforts on the nanostructured Si-based materials, the understanding and application of microsized Si electrodes are significantly lacking. In this work, for the first time, we demonstrate that combination of three-dimension (3D) conductive network and all-fluorinated electrolyte can significantly improve the cycling stability of microsized Si electrode. The galvanostatic discharge/charge test showed that the microsized Si electrode with 3D conductive network delivered a reversible capacity of 2084 mAh g−1 at 1000 mA g−1 after 200 cycles in all-fluorinated electrolyte. Further analysis using X-ray photoelectron spectroscopy, transmission electron microscopy and cyclic voltammetry demonstrated that its excellent performances are attributed to enhanced electron conductivity and forming a robust, uniform and LiF-dominated solid-electrolyte interphase layer.
Combination of three-dimension conductive network and all-fluorinated electrolyte can significantly enhance the cycling stability of microsized Si electrode by enhancing conductivity and forming a uniform, flexible and LiF-dominated solid-electrolyte interphase layer. Display omitted
•Combination of 3D conductive network and all-fluorinated electrolyte can significantly enhance the cycling stability of μmSi electrode.•The 3D conductive network was constructed through amide and ester bonds among –COOH of PAA, –NH2 of SCNT and –OH of μmSi particles.•The all-fluorinated electrolyte can improve the stability of electrode/electrolyte interface, forming a uniform, flexible and LiF-dominated SEI layer.
Solar‐driven upgrading of biomass‐derived 5‐hydroxylmethylfurfural (HMF) to 2,5‐furandicarboxylic acid (FDCA) holds great promise for sustainable production of bio‐plastics and resins. However, the ...process is limited by poor selectivity and sluggish kinetics due to the vertical coordination of HMF at relatively strong metal sites. Here, we purposely developed a Cu(II) porphyrin framework featuring side‐chain incorporated urea linkages, denoted as TBUPP−Cu MOF, to render HMF a weak hydrogen bond at the urea site and flat adsorption via π–π stacking with the benzene moiety. The unique configuration promotes the approaching of −CHO of HMF to the photoexcited porphyrin ring towards kinetically and thermodynamically favourable intermediate formation and subsequent desorption. The charge localisation and orbital energy alignment enable the selective activation of O2 over the porphyrin to generate ⋅O2− and 1O2 instead of highly oxidative H2O2 and ⋅OH via spin‐flip electron transfer, which drive the ambient oxidation of proximal −CHO. The effective utilisation of redox species and circumvented over‐oxidation facilitate a FDCA selectivity of >90 % with a high turnover number of 193 molHMF molCu−1. The facile purification of high‐purity FDCA and zero‐waste recycling of intermediates and durable catalyst feature TBUPP−Cu MOF a promising photo‐oxidation platform towards net‐zero biorefining and organic transformations.
A urea‐incorporated porphyrin framework can activate molecular oxygen to generate selectively ⋅O2− and 1O2 and enable the flat adsorption of 5‐hydroxymethylfurfural in a low‐energy configuration leveraging on hydrogen bonding and π–π stacking, leading to highly efficient photo‐oxidation that produces bioplastic monomers from renewable feedstocks without over‐oxidation and photo‐corrosion.
Electrocatalytic carbon dioxide reduction reaction (CO
RR) to produce ethylene (C
H
) is conducive to sustainable development of energy and environment. At present, most electrocatalysts for C
H
...production are limited to the heavy metal copper, meanwhile, achieving metal-free catalysis remains a challenge. Noted piperazine with sp
N hybridization is beneficial to CO
capture, but CO
RR performance and mechanism have been lacking. Herein, based on linkage engineering, we construct a novel high-density sp
N catalytic array via introducing piperazine into the crystalline and microporous aminal-linked covalent organic frameworks (COFs). Thanks to its high sp
N density, strong CO
capture capacity and great hydrophilicity, aminal-linked COF successfully achieves the conversion of CO
to C
H
with a Faraday efficiency up to 19.1 %, which is stand out in all reported metal-free COF electrocatalysts. In addition, a series of imine-linked COFs are synthesized and combined with DFT calculations to demonstrate the critical role of sp
N in enhancing the kinetics of CO
RR. Therefore, this work reveals the extraordinary potential of linkage engineering in COFs to break through some catalytic bottlenecks.
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