State Key Laboratory for Advanced Metals and Materials

Nanoscale Al₂O₃ coating by an atomic layer deposition technique enabled safe and dendrite-free Zn anodes for rechargeable aqueous zinc-ion batteries.

Strain sensors with both of stretchability and ultrahigh sensitivity have been designed and fabricated for various wearable monitoring applications.

), an ultralow limit of detection (0.1% strain), and excellent reliability and stability (>15 000 cycles for pressuring and >10 000 cycles for stretching). In particular, the maximum sensing range is up to 400%, much wider than that of the sensor recently reported. More significantly, the strain sensors are able to distinguish between touch/compressive (resistance decrease) and tensile (resistance increase) deformation, which has not been explored before. This interesting property of strain sensors is due to the micro-contact of nanomaterials in a liquid environment. The sensing liquid of the device can be refilled when it fails, and this enables the recycling of the materials and reduces the waste rate. Therefore, it is attractive and promising for practical applications in multifunctional wearable electronics such as the detection of acoustic vibration, human vocalization and other human motions.

Reducing lattice thermal conductivity is one of the most effective routes for improving the performance of thermoelectric materials.

A hybrid membrane with asymmetric microtopology and anisotropic wettability realizes highly efficient fog collection.

Metallic glasses are metastable and their thermal stability is critical for practical applications, particularly at elevated temperatures. The conventional bulk metallic glasses (BMGs), though exhibiting high glass-forming ability (GFA), crystallize quickly when being heated to a temperature higher than their glass transition temperature. This problem may potentially be alleviated due to the recent developments of high-entropy (or multi-principle-element) bulk metallic glasses (HE-BMGs). In this work, we demonstrate that typical HE-BMGs, i.e., ZrTiHfCuNiBe and ZrTiCuNiBe, have higher kinetic stability, as compared with the benchmark glass Vitreoy1 (Zr41.2Ti13.8Cu12.5Ni10Be22.5) with a similar chemical composition. The measured activation energy for glass transition and crystallization of the HE-BMGs is nearly twice that of Vitreloy 1. Moreover, the sluggish crystallization region ΔTpl-pf, defined as the temperature span between the last exothermic crystallization peak temperature Tpl and the first crystallization exothermic peak temperature Tpf, of all the HE-BMGs is much wider than that of Vitreloy 1. In addition, high-resolution transmission electron microscopy characterization of the crystallized products at different temperatures and the continuous heating transformation diagram which is proposed to estimate the lifetime at any temperature below the melting point further confirm high thermal stability of the HE-BMGs. Surprisingly, all the HE-BMGs show a small fragility value, which contradicts with their low GFA, suggesting that the underlying diffusion mechanism in the liquid and the solid of HE-BMGs is different.

A self-powered and rapid-response UV photodetector with p-NiO/ZnO-nanorod array heterojunction was developed. Under a small forward bias of 0.1 mV, the UV photosensitivity exceeded the value of ~10⁵ previously reported.

Residual stress exists extensively in biological and engineering structures. Here we report that residual stress can be engineered to significantly enhance the strength and ductility of gradient materials. In-situ synchrotron experiments revealed that the strongest strain hardening occurred in the layer with the highest compressive residual stress in a gradient structure. This layer remained elastic longer than adjacent layers during tension, producing high hetero-deformation induced stress to increase strength and enhancing work hardening even after the disappearance of the compressive stress to increase ductility. This finding provides a new paradigm for designing gradient structures for superior mechanical properties.

An ‘ion reservoir’, from an internal electric field and lower Li⁺/Na⁺ adsorption energies at an anatase/TiO₂(B) interface, ameliorated Li⁺/Na⁺ storage.

In recent years, the rapid development of portable and wearable electronic products has promoted the prosperity of fiber supercapacitors (FSCs), which serve as flexible and lightweight energy supply devices. However, research on FSCs is still in its infancy and the energy density of FSCs is far below the level of lithium-ion batteries. Here, we report a facile method to prepare a novel fibrous CNT-aerogel by electrochemical activation and freeze-drying. The fibrous CNT-aerogel electrode possesses a large specific surface area, high mechanical strength, excellent electrical conductivity, as well as a high specific capacitance of 160.8 F g-1 at 0.5 mA and long cycling stability. Then we assembled a non-faradaic FSC based on a fibrous CNT-aerogel as the electrode and a P(VDF-HFP)/EMIMBF4 ionogel as the electrolyte. The introduction of the ionogel electrolyte increases the operating voltage of the FSC to 3 V, and makes the device combine the intrinsic high power density (27.3 kW kg-1) of non-faradaic SCs with an ultrahigh energy density of 29.6 W h kg-1. More importantly, the assembled FSCs show excellent flexibility and bending-stability, and can still operate normally within a wide working temperature window (0-80 °C). The outstanding electrochemical performance and the mechanical/thermal stability indicate that the assembled FSC device is a promising power source for flexible electronics.

We demonstrated the excellent microwave absorption properties of RGO/tetrapod-like ZnO composites, and investigated the effects of RGO mass fractions and thickness of composites on microwave absorption properties in the range from 2 to 18 GHz.

Fiber-shaped asymmetric supercapacitors with ultrahigh energy density and excellent mechanical stability.

Ternary composites of polyaniline/graphene oxide/Fe₃O₄ (PANI/GO/Fe₃O₄) were synthesized by a simple method and the electromagnetic absorption properties of the composites were investigated in the paper.

A deep understanding of the shaping technique is urgently required to precisely tailor the pore structure of a graphene aerogel (GA) in order to fit versatile application backgrounds. In the present study, the microstructure and properties of GA were regulated by freeze-casting using an ice crystal template frozen from -10 °C to -196 °C. The phase field simulation method was applied to probe the microstructural evolution of the graphene-H2O system during freezing. Both the experimental and simulation results suggested that the undercooling degree was fundamental to the nucleation and growth of ice crystals and dominated the derived morphology of GA. The pore size of GA was largely regulated from 240 to 6 μm via decreasing the freezing temperature from -10 °C to -196 °C but with a constant density of 8.3 mg cm-3. Rapid freeze casting endowed GA with a refined pore structure and therefore better thermal, electrical, and compressive properties, whereas the GA frozen slowly had superior absorption properties owing to the continuous and tube-like graphene lamellae. The GA frozen at -196 °C exhibited the highest Young's modulus of 327 kPa with similar densities to those reported in the literature. These findings demonstrate the diverse potential applications of GA with regulated pore morphologies and also contribute to cryogenic-induced phase separation methods.

In this paper, we report a catalyst-free topochemical method, combined with molten salt synthesis (MSS), to synthesize, on a large scale, rodlike and platelet single crystals of Nb(2)O(5). Rodlike KNb(3)O(8) and platelet K(4)Nb(6)O(17), which were fabricated as the precursors by the molten salt method, were treated by proton exchange and heat treatment to synthesize the rodlike H-Nb(2)O(5) and platelet T-Nb(2)O(5) single crystal, respectively. The synthesized niobium pentaoxides retained the rodlike and platelet shapes of their precursors. The structural changes involved in the process were investigated by Raman spectroscopy, X-ray diffraction, scanning electron microscopy, and transmission electron microscopy. A possible topochemical reaction mechanism is proposed. Furthermore, rodlike and platelet KNbO(3) powders were derived from stable H-Nb(2)O(5) and T-Nb(2)O(5), respectively.

Al-doping of SnO₂photoanodes can simultaneously improve conduction band and electron lifetime of high-performance dye-sensitized solar cells.

Recently, self-powered devices based on a p-n heterojunction have been widely reported, but there are few reports about self-powered UV detectors based on a single ZnO microwire/p-Si film with double heterojunctions. Compared with the common p-n heterojunction type devices, the fabricated devices with double heterojunctions based on a single n-type ZnO microwire and a p-type Si film exhibited excellent electrical performance such as an ideal rectification behaviour and a low turn-on voltage. At zero bias, the fabricated device can deliver a photocurrent of 71 nA, a high photosensitivity of about 3.17 × 10(3) under UV light (0.58 mW cm(-2)) illumination and a fast rising and falling time of both less than 0.3 s. Furthermore, the photocurrent increased with the rising of the optical intensity at low power intensities. The physical mechanism has been explained by energy band diagrams.

Biodegradability is very critical for biomaterials to be nanocarriers. Ideal nanocarriers should be stable enough to execute their functions, but then can be efficiently got rid of, by either biodegradation or excretion. In this work, we report the design and one-pot fabrication of a series of uniform organic-inorganic hybrid nanocapsules with a disulfide-bridged silsesquioxane framework and a particle size smaller than 100 nm for redox-triggered biodegradation. The optimal synthesis conditions were explored for balancing the nanostructure, sulfur (S) content and aggregation degree. Fluorescent molecules were also integrated into the disulfide-bridged silsesquioxane framework by a co-condensation strategy for fluorescence tracking. Dithiothreitol (DTT) as a strong model reducing agent triggered the breakdown of hybrid nanocapsules without and with PEG modification from intact nanospheres to small fragments, while intracellular glutathione (GSH) had a slightly lower capacity of biodegrading these nanocapsules. The constructed delivery system obviously inhibited the growth of A549 cancer cells due to efficient cellular uptake by an endocytosis pathway and the subsequent pH and GSH-triggered drug release. The possibility of regulating the framework and surface functionalization of hybrid nanocapsules opens new opportunities for the development of silica-based degradable hybrid nanocarriers for promising drug delivery.

Potassium thiocyanate as a cheap additive effectively eliminates the hysteresis effect of perovskite solar cells.

Traditional alloy design depends heavily on “trial and error” experiments, which are neither cost-effective nor efficient, particularly for the development of high-entropy alloys (HEAs) using a broad composition space. Herein, we combine a machine learning (ML) model with phase diagram calculations (CALPHAD) to design Ti-Zr-Nb-Ta refractory HEAs with a desirable hardness. The extreme gradient boosting (XGBoost) algorithm is used to train the ML model based on the Ti-Zr-Nb-Ta HEA hardness dataset from CALPHAD-assisted experiments. As a result, the most important features (i.e., the Ta content, melting point, and entropy of mixing) are determined via feature selection and model optimization. Moreover, the high performance of the ML model is validated experimentally, and the prediction accuracy reaches 97.8%. This work provides not only an interpretable ML model that can be used to predict the hardness of Ti-Zr-Nb-Ta HEAs but also feasible guidance for the development of HEAs with desirable hardness.