High-capacity anode materials have stimulated much attention to developing high-performance lithium-ion batteries. However, high-capacity anode materials commonly suffer from the pulverization matter that greatly hinders their practical applications, especially in terms of the high proportion of active materials. In this work, a Ga2O3 nanowire electrode is synthesized by thermal evaporation and immediately used as an anode without the aid of binders and conductive additives. The 3D interconnected architecture of the Ga2O3 nanowire electrode shortens lithium diffusion lengths and expedites reaction kinetics. The Ga2O3 nanowires exhibit high elasticity and a self-healing ability which is inherited from metallic Ga formed during the electrochemical transition process, thus circumventing the formidable pulverization issue to a certain extent. Benefiting from the unique structural, mechanical, and chemical attributes, the as-grown Ga2O3 nanowire electrode gives a high initial lithiation capacity of 1462 mAh g−1 under a current density of 0.1 ​A ​g−1. It delivers good cyclic stability with a reversible capacity of 445 mAh g−1 after 200 cycles at 0.5 ​A ​g−1. Furthermore, the investigation of lithium storage behaviors indicates the high rate capability of Ga2O3 nanowires. This paper contributes to understanding binder- and conductive additive-free electrodes consisting of high-capacity active materials from various viewpoints.

Developing efficient oxygen evolution reaction (OER) electrocatalysts is of great importance for sustainable energy conversion and storage. Ni-based catalysts have shown great potential as OER electrocatalysts, but their performance still needs to be improved. Herein, we report the multiple metal doped nickel nanoparticles synthesized via a simple oil phase strategy as efficient OER catalysts. The FeMnMoV–Ni exhibits superior OER performance with an overpotential of 220 ​mV at 10 ​mA ​cm−2 and a long-term stability of 250 ​h in 1 ​M KOH solution. In situ Raman analysis shows that the NiOOH site works as the active center and multiple metallic dopants facilitate the formation of NiOOH. Mo and V dopants promote the formation of high-valence state of Ni sites, and Mn dopants increase the electrochemical active surface area and expose more active sites. This work provides a novel strategy for catalyst design, which is critical for developing multiple metal doped catalysts.

Tactile sensors can transform the environmental stimuli into electrical signals to perceive and quantify the environmental information, which show huge application prospects. The development of bionic robots and wearable devices towards intelligence has put high demands on the performance of tactile sensor arrays. Herein, the current state-of-the-art tactile sensor arrays over recent years have been summarized, from sensor array fabrication to advanced applications. The main preparation methods of patterned array including screen printing, 3D printing, laser microprocessing, and textile technology are discussed in detail. Strategies to optimize the signal crosstalk caused by flexible high-density sensor arrays are systematically introduced from the perspective of structure design and circuit design. Furthermore, advanced tactile sensors are not limited to a single pressure sensing function, and hence the development of multimodal detection for sensors has been discussed. In order to promote the adaptability in applications, stretchable and self-powered versatile integration scheme for advanced sensing are briefly described. Then, by means of machine learning and neural networks, it is possible to deeply explore the information embedded in the tactile acquisition signal with enriched application scenarios. Finally, the current challenges and the future perspectives for flexible tactile sensor arrays towards practical use are provided.

Bismuth-based materials are ideal electrodes for sodium-ion batteries (SIBs) due to their high capacity and low cost. However, conventional solid bismuth materials still suffer from severe volume expansion during the reaction process, which hinders its application. Herein, single-crystal bismuth nanospheres with diameters in the range of 200–400 ​nm were successfully prepared with the Na–Bi alloying mechanism studied using in-situ XRD, which confirms a stepwise process of Bi→NaBi→Na3Bi with large volume variation. To address the volume change issue, we introduce a porous structure into the bulk of Bi crystals, which alleviated its volume expansion and suppressed its cyclic failure. An in-situ TEM experiment is further carried out to verify this effective structure-modification strategy, demonstrating its applicable feature for electrode design and performance enhancement.

Lithium-ion batteries have long been used in electronic products and electric vehicles, but their energy density is slowly failing to keep up with demand. Because of its extraordinarily high theoretical specific capacity, silicon is regarded as the most potential next-generation anode material for practical lithium-ion batteries. However, its unavoidable volume expansion issue can cause electrode deformation and loss of electrical contact during cycling, resulting in significant performance reduction. This work reviews and evaluates the modification measures of Si, SiO, and SiO2 as anode materials in order to address the challenges that silicon-based anode materials encounter. We not only review their lithium storage mechanism, but also focus on nanostructure designing and hybridizing to improve the electrochemical performance of silicon-based anodes. The silicon-based anodes can exhibit exceptional capacity retention and excellent rate performance after structural optimization and hybridization, which will greatly facilitate their commercial application. Finally, we discuss our thoughts and recommendations for the future development of silicon-based materials.

Polyanion cathodes are credited for its thermal stability and better safety, no matter in lithium ion batteries or sodium ion batteries. Polyanion oxides with phosphate groups came to the public's attention in 1997, and the representative material is LiFePO4, which has been widely applied and plays a huge role in the field of powder batteries and energy storage system. However, owing to the low lithiation potentials and storage sites, the energy densities of polyanion cathodes have been restricted, resulting of low-endurance and limited application scenarios. Accordingly, here, we use cheap and environmental friendly raw materials as precursors to synthesis high energy density LiMn0.6Fe0.4PO4@C cathode by a simple spray-drying and high temperature calcination process. The self-designed liquid polyacrylonitrile (LPAN) is added for the intention of nanoparticle coating, conductive network construction and particle granulation. The low-cost and carbon-coated LiMn0.6Fe0.4PO4 cathode exhibits excellent reversible capacity, low electrochemical polarization and excellent rate capacity, which maintains 93.5% capacity retention after cycling 1000 times at 5C. The work introduces a new avenue to fabricate olivine structure cathodes with outstanding electrochemical performance for the high energy density lithium ion batteries.

Regulating the electronic structure of the metal electrocatalyst is fundamental for its performance optimizing. The electronic states of the active metal centers are highly dependent on their coordination environment, especially when bonding is formed. The π back-bonding can induce great electron density redistribution around metals, yet it is barely applied in electrocatalyst design. Herein we electrodeposited metallic cobalt on black phosphorus (BP) nanosheets, forming BP-Co with a unique π back-bonding on the interfaces. The BP-Co exhibited high electrocatalytic activity and stability for hydrogen evolution reaction in alkaline electrolyte. The electrochemical and spectroscopic characterizations demonstrated that the BP acted as σ donor and π acceptor to coordinate with electron-rich metallic Co, similar to the phosphine complex. The directional σ bond strengthen the relationship between BP and Co, while the non-directional π bond accelerated the in-plane electron transfer. The π back donation also decreased the oxophilicity of Co to make BP-Co resist the poison from oxygen species. This study can intrigue new thinking prospective for the electrocatalyst design.

Metamaterials such as architected lattice structures have aroused broad interest in being applied as mechanical supports for their lightweight and custom-shaped capabilities. Although various prior efforts have been devoted, a multiscale fabrication of micro-nano lattice structures without penalizing the mechanical properties is still a challenging but highly desirable task. Here we put forward a strategy to produce a mechanically enhanced micro-nano lattice structure by conformally depositing a CoCrFeNiTi high-entropy alloy (HEA) coating layer onto a three-dimensional (3D) printed polymer skeleton. The template for the 3D printing employs a six-membered tricapped trigonal prism (6M-TTP) structure derived from a medium-range order structure motif in amorphous alloys. The topological complexity of the 6M-TTP can substantially avoid the stress concentration by offering stress-release channels, while the HEA film incorporating with amorphous and nanocrystalline constituents can further reinforce the lattice architecture through its size hardening effect. Benefitting from the above, the fabricated polymer/HEA-hybrid lattice exhibits a high specific compressive strength (∼0.055 ​MPa ​kg-1 m3 at a density below 500 ​kg ​m-3), a superior elastic recoverability (∼70% recovery rate under >30% compression), an enhanced plasticity (40% strain) and a high specific modulus (0.135 ​MPa ​kg-1 m3). Our strategy initiates a perspective way to fabricate multiscale micro-nano lattice structures with improved mechanical properties, which could be extended to widespread metamaterial research.

The world has been moving rapidly to find new eco-friendly energy sources. Water electrolysis consists of two reactions of Oxygen Evolution Reaction (OER) and Hydrogen Evolution Reaction (HER), whereas the OER is considered the rate-limiting step. The most commercialized electrode for OER in the alkaline electrolyte is Ni foam, but its original surface is hydrophobic. It is possible to accelerate the adsorption and desorption process of reactants and products during OER by adding hydrophilic functional groups such as –OH on the surface of Ni foam. In this study, a novel Gas-Liquid Interfacial Plasma (GLIP) engineering at room temperature was successfully applied to modify the Ni foam surface dilute (1 ​M) HNO3 solution. At a current density of 400 ​mA ​cm−2, GLIP-treated Ni foam electrodes at 1 ​M HNO3 concentrations showed OER overpotentials of 458 ​mV. Among all, GLIP with 1 ​M HNO3 treatment of 30 ​min showed 129 ​mV less overpotential than the nickel foam before treatment. In summary, GLIP can be justified as an environmentally friendly and efficient surface treatment to improve the wettability and OER performance of Ni-based electrodes in water electrolysis.

The influence of heat exchanger structure on hydrogen absorption-desorption performance of hydrogen storage vessel was studied, in which the AB5 (La0.25Ce0.75Ni4.4Al0.1Mn0.1Co0.4) hydrogen storage alloy was used as a typical representative. In order to obtain the data on reaction enthalpy, the PCT curve of the alloy was measured with three different temperatures, and the linear fitting was carried out according to the Van't Hoff relation curve. The SMCR (Spiral-mini-channel Reactor) reactor structure was adopted. The heat transfer method and its simplified model were studied by finite element method to explore the effect of size of heat transfer structure, particularly for heat pipe diameter, on the hydrogen absorption-desorption performance of hydrogen storage alloy in the vessel.

A hot-extruded Mg-5Ga alloy was subjected to ageing treatment at 150 ​°C, 190 ​°C and 230 ​°C. The microstructures and mechanical properties of the extruded and aged alloy were examined in this study. Microstructure examinations suggested that particle-shaped and rod-shaped Mg5Ga2 were precipitated in the alloy after peak ageing treatment. The extruded alloy showed the yield strength, ultimate tensile strength and elongation to fracture of 157.6 ​MPa, 248.6 ​MPa and 17.5%, respectively. After peak ageing, the yield strength and ultimate tensile strength can be enhanced by as much as 15.7% and 8.6% reaching 182.3 ​MPa and 270 ​MPa, respectively. The improvement of the tensile strengths is mainly attributed to the enhanced precipitation strengthening by newly formed fine Mg5Ga2 precipitates. The ductility of the alloy was slightly increased by peak ageing at low temperatures (150 ​°C and 190 ​°C), but remarkably decreased by peak ageing at high temperature (230 ​°C) due to the formation of coarsened Mg5Ga2 particles which easily initiated the cracks during tensile deformation.

Mo–60Si–5B coating doped with 0.5 ​at% La was prepared on niobium silicon based alloy by spark plasma sintering. The microstructure and wear behavior of the 0.5La–Mo–60Si–5B (0.5La-MSB) coating were investigated. The results show that the mean grain sizes of the Mo–60Si–5B (0La-MSB) and 0.5La-MSB coatings are calculated to be 3.27 ​μm and 2.85 ​μm, respectively. The addition of La plays a role of refining the grains of 0.5La-MSB coating. The specific wear rate of 0.5La-MSB coating is decreased by up to 26.8% at the oscillation frequency of 20 ​Hz and the sliding load of 11 ​N compared to 0La-MSB coating. The anti-friction performance of Mo–60Si–5B coating is modified by the addition of 0.5 ​at.% La. The improvement of anti-friction performance of the Mo–60Si–5B coating is due to the increased hardness and the provided lubrication function by La2O3.

Two-dimensional (2D) layered materials are assembled through the intralayer covalent bonds and interlayer van der Waals (vdWs) interactions. The relatively weak interlayer vdWs interactions result in the weak interlayer mechanical coupling between layers, which strongly impacts the overall mechanical properties of multilayer 2D materials or heterostructures. Experimentally probing the interlayer mechanical coupling is of vital importance on the accumulation of fundamental parameters for their applications in flexible and stretchable devices, yet there are hardly comprehensive reviews in this research field. In this review, we firstly introduce the probing methods of interlayer mechanical coupling, including high-frequency and ultralow-frequency Raman characterizations, nanoindentation of multilayer 2D materials or heterostructures, surface indentation, pressurized blister test, characterization of spontaneously formed nanoblisters, and nano-friction tests. Based on the analysis and comparison of the existing methods and results, we also discuss the advantages and limitations of each method. Finally, the challenges and opportunities in this promising field are discussed. This review summarizes the recent progress in the probing of interlayer mechanical coupling of 2D layered materials and will provide important reference for the rational design of flexible and stretchable devices.

Chevrel phase Mo6S8 has attracted great interest because of its capability to accommodate different types of small cations through reversible topotactic redox reactions. However, the intercalation mechanism of Mo6S8 is still far from being fully understood owing to the complexity of the crystal structure and limitation of the probe tools. In our study, the reaction mechanism of Li ​+ ​intercalation into Mo6S8 was studied as a model by in-situ tender X-ray absorption spectroscopy (itXAS) in the viewpoint of local structure. According to the isobestic points of the 1st derivative, the discharge process is divided into five regions while the charge process is divided into four regions, where most of the regions are assigned to the two-phase transition reactions. The intensity change of the two spectroscopic features of the 1st derivative is found to be correlated, implying that the intercluster bond length directly affects the localization of the unoccupied states of the intracluster bond. The asymmetric evolution of the intensity of a’ and b’ as well as the asymmetric partition of reaction regions demonstrate the asymmetry of the reaction path in discharge and charge process. The results help to clarify the remaining debates on the phase transitions. Besides, itXAS is demonstrated to be a powerful tool to study the reaction mechanism of Mo6S8, which is complementary to NMR, XRD and so on.

As the lightest family member of the transition metal disulfides (TMDs), TiS2 has attracted more and more attention due to its large specific surface area, adjustable band gap, good visible light absorption, and good charge transport properties. In this review, the recent state-of-the-art advances in the syntheses and applications of TiS2 in energy storage, electronic devices, and catalysis have been summarized. Firstly, according to the physical presentation of the TiS2 synthesis reaction, it can be divided into a solid phase synthesis, a liquid phase synthesis and a gas phase synthesis. Secondly, we summarize the applications of TiS2 in energy storage, electronic devices and catalytic: (1) The applications of TiS2 nanostructure in energy storage direction from the aspects of Li-ion battery (LIB), Li–S battery (LSB), Na-ion battery (NIB), K-ion battery (KIB), Mg-ion battery (MIB), solar cells and hydrogen storage; (2) The applications of TiS2 nanostructures in various electronic devices from thermoelectric devices, high power lasers and flexible devices; (3) Applications based on energy catalysis and environmental catalysis. Based on the various synthetic technologies and wide applications of TiS2, we firmly believe that the challenges of TiS2 will be solved and become a hot star material in the future. Finally, we discuss the future scope and the current challenges arising from this fascinating material.

Metallic glass nanoparticles hold great promise as nonenzymatic glucose sensors due to their rich low-coordinated active sites and high biocompatibility. However, their non-periodic atomic structure and unclear structure-property relationship pose significant challenges for realizing and optimizing their sensing performance. In this work, Pd–Ni–P metallic glass nanoparticles with variable compositions were successfully prepared as nonenzymatic glucose sensors via a laser-evaporated inert-gas condensation method. The electrochemical tests show that the sensor based on Pd41·25Ni41·25P17.5 nanoparticles shows a wide linear detection range (0.003–1.31 ​mM), high sensitivity (516 ​μA ​mM−1 ​cm−2), and high stability (∼97.8% current retention after 1000 cycles). Local structural investigations using synchrotron pair distribution function and high-resolution microscopic techniques reveal a strong structural correlation within short-to medium-range orders in the Pd41·25Ni41·25P17.5 nanoparticles, which can be well retained after electrochemical cycling. These atomic-scale structural characteristics might be responsible for the high sensing performance. This study demonstrates the high applicability of Pd–Ni–P metallic glass nanoparticles as sensitive and stable non-enzymatic glucose sensors.

Superparamagnetic properties and fine-tuning of colloidal Fe3O4 nanoparticles are important for their widespread biomedical applications. Herein, colloidal Fe3O4 nanoparticles (NPs) of different sizes (8–20 ​nm) were prepared, and their hydrophilization with SiO2 shell coating to be Fe3O4@SiO2 core-shell had been realized successively. The size of Fe3O4 NPs was controlled by different heating rates. Transmission electron microscope (TEM), powder X-ray diffractometry (XRD), and vibrating sample magnetometer (VSM) were performed to examine the morphology, crystallinity, and magnetic properties of the prepared Fe3O4 and Fe3O4@SiO2 core-shell NPs, respectively. In addition, high resolution transmission electron microscope (HRTEM) results suggested that Fe3O4 NPs had well crystallization. Enabled by such, their superparamagnetic properties can be fine-tuned accordingly and cater to their potential applications.

Water environmental pollutants have become one of the most serious environmental issues, and the removal of various environmental pollution (dyes, phenols, pesticides, heavy metal ions, etc.) is of particular concern because of their toxicity and refractory. Compared to conventional eliminating routes, photoelectrocatalysis (PEC), is considered as a promising strategy since it combines the advantages of photocatalysis (PC) and electrocatalysis (EC). However, it still encounters bottlenecks of scarce reaction sites and low product selectivity, restricting its development toward practical applications. In recent years, various of g–C3N4–based composites were used for the remediation of these typical environmental pollutants. Given this situation, this review summarizes the latest progress in the design and preparation of novel g–C3N4–based composites and their PEC degradation different pollution in the water environment. Some removal mechanisms are briefly discussed, and the prospects are presented for further research.

Transition metal phosphides have been recognized as promising electrocatalysts for oxygen evolution reaction (OER) due to their low cost and high activity. However, the insufficient exposed active region limited the OER performance. Recently, the introduction of sacrificial dopants has been considered an effective strategy to enlarge the surface area. Herein, the Zn dopants are introduced in NiFe phosphide (NiFeZnP) nanosheet, which work as the sacrificial dopants to generate more exposed active NiFe sites and promote the formation of the NiFeOOH active phase during OER process. The optimized Zn-doped NiFeP catalyst shows an overpotential of ≈203 ​mV to reach a current density of 10 ​mA ​cm−2 in 1 ​M KOH, and a stability of 100 ​h at 1000 ​mA ​cm−2. Overall, this work provides a sacrificial Zn doping strategy to prepare highly efficient OER electrocatalysts.

To satisfy the demand of zinc oxide (ZnO) with advanced muti-functional properties, significant efforts have been made in synthesizing ZnO with various structure and morphology. In particular, hydrothermal method has attracted considerable attentions, in which Zn4CO3(OH)6·H2O (ZCHH) is commonly found as a metastable precursor. However, the formation and crystallization mechanisms of ZCHH are still lacking and urgently needed. In the present study, the crystallization pathway of ZCHH was systematically investigated, and the results demonstrate that the amorphous zinc carbonate (AZC) was an even more unstable precursor. AZC nanoparticles typically aggregated to form one-dimensional (1D) ZCHH nanorods, however, two-dimensional (2D) ZCHH nanofilms were obtained in the presence of a certain concentration of calcium ion. The results suggest that calcium ions could promote the partial dissolution of AZC and facilitate the aggregation of AZC nanoparticles to form crystalline nanofilm. Moreover, 2D ZnO nanofilms could be obtained by heat treatment of the ZCHH nanofilms. The calcium ion mediated nonclassical crystallization pathway provides inspiration for fabrication of ZnO with controlled morphology and offers new opportunities for inorganic regulated material synthesis.