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Macroporous electrodes with multi-scaled nanostructures are simply synthesized by sequentially immersing a wire in different plating solutions through the mechanism of structural catalysis and nano-‘reinforced concrete’.

While covalent drug discovery is reemerging as an important route to small-molecule therapeutic leads, strategies for the discovery and engineering of protein-based irreversible binding agents remain limited. Here, we describe the use of yeast display in combination with noncanonical amino acids (ncAAs) to identify irreversible variants of single-domain antibodies (sdAbs), also called VHHs and nanobodies, targeting botulinum neurotoxin light chain A (LC/A). Starting from a series of previously described, structurally characterized sdAbs, we evaluated the properties of antibodies substituted with reactive ncAAs capable of forming covalent bonds with nearby groups after UV irradiation (when using 4-azido-l-phenylalanine) or spontaneously (when using

A two-step modification for the electrochemical performance of Si-based anodes for LIBs is achieved in this study. Firstly, the Cr element is chosen as the doped media into Si bulk via a HEBM method and the fabricated Si-Cr precursors consist of nanocrystalline Si, CrSi2, and amorphous Si. The electrochemical analysis reveals that all ball-milled samples have a similar lithiation/delithiation mechanism with raw Si but the generation of cr-Li3.75Si can be effectively suppressed in the initial stage. The introduction of Cr can enhance cycle stability, volumetric capacity, coulombic efficiency, and electrical conductivity for Si-Cr alloys. The abnormal performance degradation phenomenon in previous Si-CuO system cannot be found here and the suggested Cr ratio is at least 15%. Furthermore, the selected Si85Cr15 precursor is conducted a carbon-coating treatment at 800 ℃, where it shows a 100- and 250-cycle capacity retention of ~93% at 0.2C and ~80% at 0.5C, respectively. The excellent cycle performance is considered related to the limited microstructure change of Si85Cr15@c-PDA due to a certain high-temperature tolerance of CrSi2 at 800 ℃. Meanwhile, it is also attributed to the synergistic effect of CrSi2 and c-PDA, with which Si85Cr15@c-PDA electrode possesses a stable structure and impedance change during the cycles.

It is an inevitable choice to find efficient and economically-friendly electrocatalysts to reduce the high overpotential of oxygen evolution reaction (OER), which is the key to improve the energy conversion efficiency of water splitting. Herein, we synthesized Cu2S/Ni3S2 catalysts on nickel foam (NF) with different molar ratios of Ni/Cu by a simple two-step hydrothermal method. Cu2S/Ni3S2-0.5@NF (CS/NS-0.5@NF) effectively reduces the overpotential of OER, displaying small overpotentials (237 mV@100 mA cm−2 and 280 mV@500 mA cm−2) in an alkaline solution, along with a low Tafel slope of 44 mV dec−1. CS/NS-0.5@NF also presents an excellent durability at a relatively high current density of 100 mA cm−2 for 100 h. The excellent performance is benefited by the prominent structural advantages and desirable compositions. The nanosheet has a high electrochemical active surface area and the porous structure is conducive to electrolyte penetration and product release. This work provides an economically-friendly Cu-based sulfide catalyst for effective electrosynthesis of OER.

Recent research pointed out that the degree of inflammation in the adventitia could correlate with the severity of atherosclerotic plaques. Intravascular photoacoustic endoscopy can provide the information of arterial morphology and plaque composition, and even detecting the inflammation. However, most reported work used a non-coaxial configuration for the photoacoustic catheter design, which formed a limited light-sound overlap area for imaging so as to miss the adventitia information. Here we developed a novel 0.9 mm-diameter intravascular photoacoustic catheter with coaxial excitation and detection to resolve the aforementioned issue. A miniature hollow ultrasound transducer with a 0.18 mm-diameter orifice in the center was successfully fabricated. To show the significance and merits of our design, phantom and ex vivo imaging experiments were conducted on both coaxial and non-coaxial catheters for comparison. The results demonstrated that the coaxial catheter exhibited much better photoacoustic/ultrasound imaging performance from the intima to the adventitia. This article is protected by copyright. All rights reserved.

Two-dimensional (2D)-layered atomic arrangement with ultralow lattice thermal conductivity and ultrahigh figure of merit in single-crystalline SnSe drew significant attention among all thermoelectric materials. However, the processing of polycrystalline SnSe with equivalent thermoelectric performance as single-crystal SnSe will have great technological significance. Herein, we demonstrate a high zT of 2.4 at 800 K through the optimization of intrinsic defects in polycrystalline SnSe via controlled alpha irradiation. Through a detailed theoretical calculation of defect formation energies and lattice dynamic phonon dispersion studies, we demonstrate that the presence of intrinsically charged Sn vacancies can enhance the power factor and distort the lattice thermal conductivity by phonon-defect scattering. Supporting our theoretical calculations, the experimental enhancement in the electrical conductivity leads to a massive power factor of 0.9 mW/mK2 and an ultralow lattice thermal conductivity of 0.22 W/mK through the vacancy-phonon scattering effect on polycrystalline SnSe. The strategy of intrinsic defect engineering of polycrystalline thermoelectric materials can increase the practical implementation of low-cost and high-performance thermoelectric generators.

The huge volume change of Si anode with fast capacity degradation limits its commercialization in LIBs. The co-introduction of metal and O elements into the Si bulk fabricating Si-metal silicide-Si oxides composites has been proven an effective way to overcome this issue. Among them, Si-CuO composites, due to financial feasibility and environmentally compatibility, have attracted much attention recent years but still with the unsatisfactory cycle performance. In order to optimize the cycle stability of Si-CuO composites, NiO is firstly introduced into the Si-CuO system with different proportion from 10 % to 20 % by a facile and low-cost HEBM method. The study reveals that Si72CuO8NiO20, with the least volume change percentage of ~ 133 %, has a highest capacity retention of ~ 86. 9% after 100 cycles at 0.2 C and average coulombic efficiency of ~ 99.4 % as well as a competitive volumetric capacity of ~ 1700 Ah·L-1 based on the 2nd lithiation. These results confirm the effectiveness of the NiO introduction to improve the cycle performance of the Si-CuO composites. Moreover, in order to make sure the ball-milled Si-CuO-NiO precursors can be well compatible with the high-temperature post-treatment of coating a carbon layer, the thermal stability of Si72CuO8NiO20 is also conducted with the best cycle stability at 600 °C.

Silicon (Si) is a promising anode material for Li-ion batteries but its application is limited due to its severe volume change during the lithiation/delithiation process, leading to a fast degradation of cycle performance. Applying transition metals to dope into the bulk Si forming active/inactive silicide phase is proved as an effective and practical method to solve the issue. However, the classic high-energy ball milling method is faced with the challenges of strict requirements to the machine, long-time working and difficulty to control the morphology of the product. Aiming to this point, the present study proposes a facile and “softer” method via coating the polydopamine (PDA) with the assistance of CuCl2·2H2O followed by a high-temperature annealing process to successfully fabricate the Si-based anode material with a unique structure of Si-Cu3Si@c-PDA. We firstly achieved the doping of Cu3Si and the coating of carbon layer simultaneously on the surface of Si. Owing to the synergistic effect of carbonized PDA layer and doped Cu3Si phase, both structural stability and electronic conductivity of electrode have been significantly enhanced. The Si-Cu3Si@c-PDA composite anode not only exhibited a high initial reversible capacity of 2356.7 mAh·g-1 with an initial coulombic efficiency of 83.6%, but also demonstrated a good capacity retention of 89.7% after 100 cycles at the current density of 400 mA·g-1. We believe this work would pave a novel way to improve the Si-based anode material.

An N-type lead telluride (PbTe0.95) thermoelectric material prepared by a conventional sintering method (CSM) has been investigated for the first time. N-type nanosized lead sulfide (PbS) fabricated using the one-pot synthesis method was embedded in the PbTe0.95 matrix to enhance the thermoelectric efficiency, zT. It was successfully demonstrated that the CSM could be used to prepare the nanosized n-type PbTe composite with the zT value of ∼1 at 673 K. This value is comparable to the one synthesized using spark plasma sintering and hot press sintering methods. We attribute the enhanced zT to the strong phonon scattering induced by the nanosized PbS. Meanwhile, the nanosized PbS particles, acting as a sintering additive, enhanced the sintering behavior of as-prepared PbTe0.95 powder. It was found that the introduction of 3 wt% nanosized n-type PbS could reduce the lattice thermal conductivity of the pristine sample of PbTe0.95 from 0.914 W m−1 K−1 to 0.59 W m−1 K−1. Finally, a single parabolic band model (SPB) demonstrated that the 3 wt% was the optimized doping amount for the PbS-doped PbTe0.95 composites.

Supercapacitors are characterized by high power density, but a bottleneck exists regarding their limited energy density due to the conflict between achieving high mass loading and high specific capacitance with the current structural design. Although there have been concerted efforts to develop supercapacitors with high specific capacitance using nanostructured materials, the total mass loading of active materials is confined by their nano-scale thickness. Here we report an effective strategy to integrate active materials and current collectors through binding active materials and current collectors together in a 3D style. Contrary to the conventional configuration, hollow active materials were confined inside nano-scale current collectors in this work. The resulting nano-scale electrode materials could be compressed together in a scalable style to form nanoporous Fe3O4@Ni freestanding electrodes at the desired scale. Consequently, symmetric supercapacitors were fabricated by Fe3O4@Ni electrodes, and showed a capacitance of 11.2 F cm−2, corresponding to an energy density of 94.4 mW h cm−3. The supercapacitor also exhibited an excellent cyclic capability with a capacitance retention of 107% after 10 000 cycles. The scalability of the electrode materials could be further enhanced by the addition of multiwalled carbon nanotubes (MCNTs) during the synthesis process, and the resulting 0.665-thick Fe3O4-MCNTs@Ni electrode with an Fe3O4 content of 79.4 mg cm−2 exhibited a superhigh areal capacitance of 82.6 F cm−2 as well as a high volumetric capacitance of 1242 F cm−3. This work demonstrates that large mass loading, large specific capacitance, high energy density, and good cyclability of supercapacitors can be achieved simultaneously through the effective structural design of electrodes at the multi-scale.

The manganese-based Prussian blue and its analogues (PBAs) are regarded as promising cathode materials for sodium-ion batteries (SIBs). However, the effective suppression of Fe(CN)6 vacancies and removal of the absorbed and interstitial water in their crystal structures are two critical points to achieve excellent electrochemical performances. In this study, carbon nanotubes (CNT) were employed to synthesize the hybrid KNa-MnFe(CN)6@CNT material via a facial concentration-gradient coprecipitation method. The systematic characterization of this material revealed that the water content was effectively reduced and a two-phase (monoclinic and cubic) structure was obtained. The well-designed hybrid KNa-MnFe(CN)6@CNT electrode exhibited an outstanding electrochemical performance with a very high initial discharge capacity of 164.5 mA h g−1 (ICE = 96.3%) and high capacity retention of 82.0% after 100 cycles at the current density of 20 mA g−1 in the voltage range of 2.0–4.2 V. In addition, a high rate performance of 77.3 mA h g−1 was achieved at a current density of 1 A g−1 due to the good adhesion between the PBA particles and CNT. The good structural reversibility of the KNa-MnFe(CN)6@CNT electrode was confirmed during the extraction/insertion process of alkali metal ions. Thus, this work provides a prospective strategy to develop high-performance hybrid manganese-based PBA cathode materials for SIBs.

Sodium super ionic conductor (NASICON) materials are considered as an attractive cathode in sodium-ion batteries. Although the three-electron reactions in Na3MnTi(PO4)3 have greatly enhanced the capacity of NASICON-structured materials, the low potential from Ti3+/4+ redox reaction and undesirable initial coulombic efficiency (ICE) have inhibited its practical application. Herein, NASICON structured Na3+2xMn1+xTi1−x(PO4)3 was designed and synthesized by the atomic-ratio-controlled method. Impressively, the increase in the Mn content not only significantly enhances the average voltage, but also increases the theoretical capacity with more than three-electron reactions. Na3+2xMn1+xTi1−x(PO4)3 can deliver an extra-high capacity of 181.4 mA h g−1 at 0.1C (1C = 150 mA h g−1), and 100.4 mA h g−1 at 10C during the rate tests. When x = 0.15 and 0.2, the energy density is up to 560.2 and 539.5 W h kg−1 at 0.1C, which is significantly higher than 442.4 W h kg−1 with x = 0, i.e. Na3MnTi(PO4)3. The capacity retention is 87.4% at 1C after 500 cycles and 83% at 5C after 1000 cycles, respectively. In addition, the ICE is as high as 89.2% after the introduction of more Na ions in the pristine structure. The structural evolution and electrochemical reaction mechanism were further confirmed by ex situ XRD, XPS and TEM. This work provides a new insight into controllable design of low cost, high capacity and energy density NASICON-structured materials for SIBs.

Silicon (Si) is a promising anode material for Li-ion batteries but its application is limited due to its low electronic conductivity and severe volume change during the lithiation/delithiation process. Recently, coating a carbon layer on the Si surface and doping the alloy phase into the bulk Si have been considered as effective approaches to resolve the aforementioned issues. The present study proposes a facile method via coating the polydopamine (PDA) with the assistance of CuCl2·2H2O followed by a high-temperature annealing process to successfully fabricate the Si-based anode material with a unique structure of Si-Cu3Si@C. Owing to the synergistic effect of carbonized PDA layer and doped Cu3Si phase, both structural stability and electronic conductivity of electrode have been significantly enhanced. The Si-Cu3Si@C composite anode not only exhibited a high initial reversible capacity of 1.44 mAh·cm-2 (2483 mAh·g-1) with an initial coulombic efficiency of 83.2%, but also demonstrated a good capacity retention of 91.3% after 100 cycles at the current density of 0.28 mA·cm-2 (480 mA·g-1). In particular, an excellent reversible capacity of 0.75 mAh·cm-2 (1339 mAh·g-1) after a long-term test of 400 cycles was displayed at the high current density of 1.4 mA·cm-2 (2500 mA·g-1).

To improve the photocatalytic efficiency of the N₂ reduction reaction, MXene quantum dots (Ti₃C₂-QDs) and two-dimensional (2D) nickel metal–organic framework (Ni-MOF) with different ratios were fabricated by a simple self-assembly strategy to form type II heterojunctions. The resultant composites showed enhanced absorption and excellent interfacial charge-transfer capabilities according to the optical and photoelectron properties. The optimal Ti₃C₂-QD/Ni-MOF heterostructure exhibited a considerable ammonia yield rate (88.79 μmol gcₐₜ–¹ h–¹). By means of X-ray absorption near-edge fine structure (XANES) technique, it was found that the interaction of Ti₃C₂-QD and Ni-MOF could accelerate the electron transfer, and Ni site would be the main area to enrich the electron density as well as adsorb and activate N₂. Finally, with the aid of density functional theory (DFT) calculations and in situ Fourier transform infrared spectrometry (FTIR), the reaction pathway and intermediate products were studied.

Lithium–sulfur (Li–S) batteries have been attracting great attention as promising rechargeable batteries because of their large specific capacity and high energy density. However, some technical pr...

Symmetric sodium-ion batteries possess promising features such as low cost, easy manufacturing process, and facile recycling post-process, which are suitable for the application of large-scale stationary energy storage. Herein, we proposed a symmetric sodium-ion battery based on dual-electron reactions of a NASICON-structured Na3MnTi(PO4)3 material. The Na3MnTi(PO4)3 electrode can deliver a stable capacity of up to 160 mAh g-1 with a Coulombic efficiency of 97% at 0.1 C by utilizing the redox reactions of Ti3+/4+, Mn2+/3+, and Mn3+/4+. This is the first time to investigate the symmetric sodium-ion full cell using Na3MnTi(PO4)3 as both cathode and anode in the organic electrolyte, demonstrating excellent reversibility and cycling performance with voltage plateaus of about 1.4 and 1.9 V. The full cell exhibits a reversible capacity of 75 mAh g-1 at 0.1 C and an energy density of 52 Wh kg-1. In addition, both ex situ X-ray diffraction (XRD) analysis and first-principles calculations are employed to investigate the sodiation mechanism and structural evolution. The current research provides a feasible strategy for the symmetric sodium-ion batteries to achieve high energy density.

Secondary electrocaloric effect (ECE) arising from piezoelectricity combined with crystal thermal expansion was often overlooked in ECE studies of ferroelectric ceramics. This work mainly evaluated the primary ECE (ΔTECE) and secondary ECE (∆T2) of eco-friendly BaSnxTi1-xO3 (BSnT100x, 0

Defect engineering in thermoelectric materials leads to the formation of exotic transport properties. Specifically, reduction in lattice thermal conductivity (кL) can be realized through scattering of low and high-frequency phonons by interfacial and point defects respectively. Herein we explore such phenomena by inducing dense dislocations through doping of rare earth (RE) impurities in β-(Zn1−xREx)4Sb3 [x = 0.3–0.5 at.%] as phonon scattering source of all frequencies. Lattice anharmonicity created results in an ultra-low кL of ~0.15 W/mK for β-(Zn0.997 Yb0.003)4Sb3. Vibrational properties and phonon scattering altered by the lattice anharmonicity are studied in detail through terahertz and infrared spectroscopies.

With the development of high-temperature thermoelectric materials, especially the superionic copper selenide (Cu2−xSe), thermal stability and cycling thermoelectric performance have become a great concern recently. Here we demonstrate that the excellent repeatability of the thermal cycling data of a simple Cu–Se binary system can be obtained. The thermal stability was systematically studied via measuring the thermal-cycling thermoelectric performances of Cu1.97Se samples with different rates of Se evaporation by adopting a simple and controllable method, i.e., the conventional solid-state sintering method. The samples fabricated using the conventional sintering method exhibited an optimized figure of merit of 0.8 at 800 K with very good thermal repeatability and stability from 400 K to 800 K. The results indicated that the conventional sintering method can also be adopted to fabricate materials with satisfactory thermoelectric performance. It was found that the repeatability of thermal cycling data is directly related to the sintering temperature and indirectly associated with the evaporation of Se. The Cu1.97Se samples sintered at low temperatures experienced less evaporation of Se with good thermal repeatability, while they exhibited relatively low thermoelectric performance due to high carrier concentration. Although the samples sintered at high temperatures show a large variation in the thermal cycling performance, the repeatability could be improved by the further annealing process, which reveals that good thermal stability of thermoelectric materials can be obtained via post-treatment.

Cu2SnS3 (CSS) has gained great attraction due to its constitutive earth-abundant elements and intrinsic low lattice thermal conductivity, κl, potentially providing high quality factor, B, and high zT value. However, the lack of band convergence is the bottleneck to enhancing the thermoelectric performance of Cu2SnS3 when performing the band engineering. To study the doping effect on the band structure and the thermoelectric performance, the composite Cu2Sn0.7Co0.3S3-xCuCl (x = 0, 0.1, 0.2, 0.3) (CSCS-xCuCl) has been investigated for the first time. The samples showed excellent data repeatability at high temperatures of up to 700 K. It was found that CuCl could compensate the Cu loss, enhance the phonon scattering and minimize the adverse effect on the power factor, PF. The ultralow lattice thermal conductivity could reach 0.38 W m−1 K−1 for the nominal composition of CSCS-0.3CuCl at 700 K. A peak zT of 0.56 (evaluated with no cold finger effect) was realized at 700 K when x = 0.3, which is almost double the performance of pristine samples.