Latest ArticlesHydrogel-based quasi-solid-state electrolytes (Q-SSEs) swollen with electrolyte solutions are important components in stretchable supercapacitors and other wearable devices. This work fabricates a super-tough, fatigue-resistant, and alkali-resistant multi-bond network (MBN) hydrogel aiming to be an alkaline Q-SSE. To synthesize the hydrogel, a 2-ureido-4[1H]-pyrimidone (UPy) motif is introduced into a poly(acrylic acid) polymer chain. The obtained MBN hydrogels with 75 wt% water content exhibit tensile strength as high as 2.47 MPa, which is enabled by the large energy dissipation ability originated from the dissociation of UPy dimers due to their high bond association energy. Owing to the high dimerization constant of UPy motifs, the dissociated UPy motifs are able to partially re-associate soon after being released from external forces, resulting in excellent fatigue-resistance. More importantly, the MBN hydrogels exhibit excellent alkali-resistance ability. The UPyGel-10 swollen with 1 mol/L KOH display a tensile strength as high as ~1.0 MPa with elongation at break of ~550%. At the same time, they show ionic conductivity of ~17 mS/cm, which do not decline even when the hydrogels are stretched to 500% strain. The excellent mechanical property and ionic conductivity of the present hydrogels demonstrate potential application as a stretchable alkaline Q-SSE.
Based on the coumarin skeleton, we deliberately designed two groups of fluorophores, termed as Coum-R and Naph-Coum-R, using the diphenylamino group as the electron donor, which displayed long-wavelength emissions (red spectral region), large Stokes shift (up to 204 nm), superior AIE performance, and large two-photon absorbance cross-sections (as high as 365 GM). The electron-withdrawing substituents at the 3-position of these dyes could induce a significant red-shift in their emission spectra. Preliminary imaging experiments demonstrated the capability of these dyes as two-photon fluorophores for specifically staining lipid droplets in living cells.
Covalent organic frameworks (COFs) are a class of crystalline porous organic materials with variable structures and fascinating properties. The intrinsic low conductivity impedes their widely application in optoelectronic. Iodine doping is an effective way to enhance the electrical conductivity of COFs. Here, a novel 3D imine COF with lvt topology is synthesized from two different pentacene derivatives with the same core in the form of structural complementarity. DDHP-COF is a highly crystalline material featuring high surface area of 1679 m2/g and excellent thermal stability up to 490 ℃. Upon doping with iodine, the electrical conductivity can reach as high as 1.5 × 10−2 S/m which is significantly enhanced over 6 orders of magnitude compared with the pristine COF.
Metal-organic frameworks (MOFs) have showed high promise in CO2-electroreduction, yet their generally insufficient conductivity or low electron-transfer efficiency have largely restricted the wide-spread applications. Herein, fullerene molecules (i.e., C60 and C70) have been successfully introduced into the pore-channels of a Co-porphyrin based MOF through a facile strategy. Thus-obtained hybrid materials present higher electron-transfer ability, enhanced CO2 adsorption-enthalpy and CO2 electroreduction activity. Notably, the charge transfer resistance (Rct) of C60@MOF-545-Co is almost 5 times lower of than that of MOF-545-Co, as well as 1.5 times increased for the CO2 adsorption enthalpy. As expect, the FECO of C60@MOF-545-Co (97.0%) is largely higher than MOF-545-Co (70.2%), C60@MOF-545 (19.4%), C60 (11.5%) and physical mixture (70.3%) and presented as one of the best CO2 electroreduction catalysts reported in H-cell system. The facile strategy would give rise to new insight into the exploration of powerful MOF-based hybrid materials in high-efficiency CO2 electroreduction.
A novel Au11Cd nanocluster was synthesized by developing a combined method and controlling the kinetics, and another Au26Cd5 nanocluster was also obtained after the conditions were changed in the same reaction, which could transfer to Au11Cd in a two-way style. Both alloy nanoclusters can photocatalyze the production of singlet oxygen (1O2) and exhibit enhanced efficiencies in photocatalyzing two kinds of organic oxidations involving singlet oxygen compared with their non-alloyed mother nanoclusters, indicating that the Cd-doping might be an efficient way to enhance the photocatalysis performance of gold nanoclusters and metal nanoclusters are promising photocatalysts for organic oxidation involving singlet oxygen.
Luminescent spin crossover (SCO) materials have attracted significant interest owing to their potential applications in magneto-optical switches. However, the majority of previously reported FeⅡ-based SCO complexes are adversely affected by fluorescence quenching in the solid-state. Here, we have constructed the first mononuclear FeⅡ complex decorated with an aggregation-induced emission (AIE) luminophore (i.e., tetraphenylethylene) that exhibits synergistic SCO and fluorescence behavior. Intriguingly, we obtained two types of crystals in different solvent systems, both displaying distinct magnetic bistability and fluorescence properties. The fluorescence intensity was observed to track the magnetic susceptibility, which confirmed that SCO and solid-state fluorescence operate synergistically. We introduce a novel approach for the construction of luminescent SCO compounds using an AIEgen as a luminophore, which leads to fluorescence emission in the solid-state, thus allowing us to study the synergy between SCO and fluorescence.
Antimony-based materials are considered as promising anodes for potassium ion batteries due to their high theoretical capacity and low electrode potential. However, the aggregation and bulk expansion of Sb particles in cycling will cause capacity attenuation and poor rate performance. In this paper, Sb nanoplates were designed to be embedded in flexible porous N-dopped carbon nanofibers (Sb@PCNFs) by a simple electrospinning deposition (ESD) method. In this structural design, Sb nanoplates of high capacity were employed as active materials, N-dopped carbon nanofibers were used to improve conductivity and structural stability. The introduction of pore-forming agent enables the nanofibers to possess porous structure, thus buffering the huge volume change and promoting the transfer of electrolyte/ions. More importantly, the freestanding film can be directly used as a working electrode, reducing the redundancy in the battery and the cost. Benefitting from the favorable structure, the freestanding flexible Sb@PCNFs electrode shows excellent potassium storage performance with a capacity of 314 mAh/g after 2000 cycles at 500 mA/g. This strategy of employing active material with high capacity in porous and conductive flexible nanofibers represents an effective method of achieving binder-free electrode with good electrochemical performance towards wearable energy storage devices.
In this work, Ti3C2Tx MXene with -F, -Cl and -Br surface terminations are synthesized and the effect of these halogen terminations on the lithium storage properties is investigated. A maximum Li+ storage capacity of 189 mAh/g is achieved with Ti3C2Brx MXene much higher than Ti3C2Clx and Ti3C2Fx with 138 mAh/g and 123 mAh/g, respectively. Density functional theory (DFT) calculation shows that the adsorption formation energy of halogen atoms on Ti atoms follows the trend of Ti-F > Ti-Cl > Ti-Br, leading to the same trend in the content of terminations on corresponding MXenes. In addition, inevitable exposure of MXene to oxygen causes competition between halogen and oxygen. Theoretical results show Ti3C2Brx MXene has the highest Ti to O ratio and the lowest Ti to Br ratio, the high lithium affinity of O explains the maximum Li-ion storage capacity with Ti3C2Brx MXene. This work shed light on the opportunity for achieving improved lithium storage properties of MXene electrodes by regulating the surface chemistry.
Due to its low cost and easy availability, the pitch is considered a promising precursor for soft carbon anodes. However, pitch-derived soft carbon shows a high graphitization degree and small interlayer spacing, resulting in its much lower sodium storage performance than hard carbon. We propose a novel pre-oxidation strategy to introduce additional oxygen atoms into the low-cost soft carbon precursor pitch to fabricate a defect-rich and large-interlayer spacing hard carbon anode (HPP-1100). Compared with the direct pyrolysis of pitch carbon, the sodium storage capacity of HPP-1100 is significantly improved from 120.3 mAh/g to 306.7 mAh/g, with an excellent rate and cycling capability (116.5 mAh/g at 10 C). Moreover, when assorted with an O3-Na(NiFeMn)1/3O2 cathode, the full cell delivers a high reversible capacity of 274.0 mAh/g at 0.1 C with superb cycle life. This work provides a new solution for realizing the application of low-cost pitch anodes in Na-ion batteries.
Conjugated microporous polymers (CMPs) with tunable bandgaps have attracted increasing attention for photocatalytic hydrogen evolution. However, the synthesis of CMPs usually needs expensive metal-based catalysts. Herein, we report a metal-free synthetic route to fabricate pyridyl conjugated microporous polymers (PCMPs) via a condensed polymerization between aldehyde and aryl ketone monomers. The PCMPs show widely tunable specific surface areas (347–418 m2/g), which were controlled via changing the used monomers. The PCMPs synthesized using monomers of dialdehyde and diacetylbenzene (diacetylpyridine) in the presence of pyridine exhibited the highest visible-light driven hydrogen evolution rate (9.56 µmol/h). These novel designed PCMPs provide wide adaptability to current materials designed for high-performance photocatalysts in different applications.
No. 86 Xueyuan South Road, Haidian District, Beijing
010-62199257
qkjq@cast.org.cn
Copyright © 2025 China Association for Science and Technology. All rights reserved. For all open access content, the relevant licensing terms apply.
Sponsored by the Office of the Leading Group for Cybersecurity and Informatization of CAST, and supported by Science and Technology Review Publishing House
