The microstructure and properties of as-cast Zr-2.5Nb-1X (X = Ru, Mo, Ta and Si) alloy are screened to explore novel biomedical zirconium alloys for magnetic resonance applications. Corresponding microstructure and phase transformation were characterized using X-ray diffraction (XRD), scanning electron microscope (SEM) and transmission electron microscope (TEM). Hardness test, magnetic detection and electrochemical corrosion measurements are taken to present properties. The results show that all alloys consist of α-Zr, β-Zr and ω-Zr. α-Zr and β-Zr mainly exist in the form of parallel and intersecting plates, and nanoscale ω-Zr is dispersed in β-Zr plate. Especially, blocky ω-Zr with needle-like α-Zr is only found in plate-free blocks of Zr-2.5Nb-1Mo/Ru alloy. The orientation relationship (OR) between α- Zr and ω-Zr follows \( \left[ {11\bar{2}0} \right]_{\upalpha} \)//\( \left[ {1\bar{1}01} \right]_{\upomega} \) and \( \left( {0001} \right)_{\upalpha} \)//(\( \left[ {\bar{1}011} \right]_{\upomega} \) 011)ω. Combining this OR with the OR between β-Zr and ω-Zr, the transformation relationship between β-Zr/ω-Zr and α-Zr is also discussed. Zr-2.5Nb-1Ru alloy with high corrosion potential (− 0.500 V), low corrosion rate (0.949 μm·year–1) and low magnetic susceptibility (92 × 10−6) shows great potential to be a novel biomedical implant with magnetic resonance imaging compatibility. Based on the experimental results, the possible relationship among alloying elements, microstructure and properties has been established in these Zr-2.5Nb-1X alloys. Graphical abstract

Spent hydrogenation catalysts are important secondary resources due to richness in the valuable metals of Ni, Mo and V. Recovery of valuable metals from spent catalysts has high economic value and environmental benefits since they are hazardous wastes as well. Traditional recycling processes including hydrometallurgical leaching and soda roasting-leaching have disadvantages such as generating large amounts of wastewater, long process, and low recovery efficiency of valuable metals. Thus, this paper proposed synergistic enrichment of Ni, Mo and V via pyrometallurgical reduction at 1400–1500 °C. The melting temperature and viscosity of slag were reduced through slag designing by software FactSage 7.1. The phase diagram of Al2O3-CaO-SiO2-Na2O-B2O3 was drawn, and low-temperature region (≤ 1300 °C) was selected as target slag composition. Ni, Mo, and V can be collaborative captured and recovered through the mutual solubility at molten state. Increasing the melting temperature and the amount of CaO, Na2O and C were conducive to improving the metals recovery rates. The kilogram-scale experiments were carried out, and the recovery efficiencies of Ni, Mo and V were 98.3%, 95.3% and 97.9% under optimized conditions: at 1500 °C, with the basicity of 1.0, 13.1 wt% SiO2, 7.0 wt% B2O3, 7.7 wt% Na2O and 20.0 wt% C. The distribution behavior of valuable metals was clarified by investigating the melting process of slag and the reduction in valuable metals. Ni was preferentially reduced and acted as a capturing agent, which captured other metals to form NiMoV alloys.Graphical abstract

Metal anodes based on plating/stripping electrochemistry, for instance, common alkaline metal lithium (Li), sodium (Na), potassium (K), polyvalent metal magnesium (Mg), aluminum (Al), calcium (Ca) and zinc (Zn) are imminently evoked and increasingly researched for future generation high-energy-density rechargeable batteries due to their large theoretical capacity, low electrochemical potential, and superior electronic conductivity in recent years. However, the uncontrolled dendrite formation issue induces low Coulombic efficiency, short lifespan, and hazardous security risks, hindering the actual applications of metal batteries. Among various solutions, the utilization of ferro-/piezoelectric materials for metal anodes displays active effects on decreasing local current density, suppressing dendrite growth, and tolerating volume expansion benefits from the unique ferro-/piezoelectric polarization effect. This review presents the research progress of ferro-/piezoelectric polarization effect for regulating the dendritic growth of metal anodes for the first time. First, the current challenges and strategies of metal anodes are proposed. Then, ferro-/piezoelectric materials and their working principle are discussed. Finally, the recent research progress of ferroelectric and piezoelectric materials on dynamic regulation of dendrite growth is summarized, and the future perspectives are prospected. We hope this review could draw more attention in designing metal anodes with self-polarization materials and promoting their practical applications.Graphical abstract

Ni-rich cathode materials will be primarily used as next-generation high-specific energy cathode materials in lithium-ion batteries. However, residual Li formation and cracking considerably restrict the wide application of these materials. To address the issues related to cracking, micro-sized single-crystal cathode materials without internal grain boundaries are proposed. In this study, we constructed a thin LiBO2 layer on the single-crystal LiNi0.83Co0.07Mn0.10O2 particles by solvent-free H3BO3 modification. The residual Li on the material surface decreased by 14% through the reaction of LiOH/Li2CO3 and H3BO3. The coated materials exhibited higher initial Coulombic efficiency (88.44%), higher reversible capacity (213.4 mAh·g−1 at 0.1C), and better cycling performance (91.31% retention over 50 cycles within 3.0–4.3 V at 1.0C) than the unmodified materials. Using the galvanostatic intermittent titration technique, electrochemical impedance spectroscopy (EIS), and inductively coupled plasma-optical emission spectroscopy (ICP-OES), we reveal the mechanism by which the electrochemical properties are improved upon H3BO3 modification. The superior electrochemical performances are associated with increased Li+ conductivity, lower charge transfer impedance, and suppressed transition metal dissolution. Therefore, this study demonstrates the importance of surface modification in obtaining Ni-rich single-crystal materials with enhanced performance.Graphical Abstract

Molybdenum dioxide has aroused a wide concern as anode material for lithium-ion batteries (LIBs) due to its high theoretical capacity and high density. However, it still faces the problems of large volume changes and low electronic conductivities, which limits its practical application. Herein, necklace-like N-doped carbon nanofibers encapsulating MoO2 nanospheres (MoO2@NCNFs) with Mo–C bonding have been designed to address these issues. The rational design carbon coating structure can not only enhance the electron transfer, but also markedly strengthen structural stability. As expected, the as-prepared electrode showed superior lithium storage capacity, including a high specific capacity of 1120 mAh·g−1 at 0.1 A·g−1, and good rate performance of 502 mAh·g−1 at 4.0 A·g−1 and a prolonged cycling stability of 490 mAh·g−1 capacity retention over 3000 cycles at 4.0 A·g−1.Graphical abstract

Potassium-ion hybrid capacitors (PIHCs) reconcile the advantages of batteries and supercapacitors, exhibiting both good energy density and high-power density. However, the low-rate performance and poor cycle stability of battery-type anodes hinder their practical application. Herein, phosphorus/nitrogen co-doped hollow carbon fibers (P-HCNFs) are prepared by a facile template method. The stable grape-like structure with continuous and interconnected cavity structure is an ideal scaffold for shortening the ion transport and relieving volume expansion, while the introduction of P atoms and intrinsic N atoms can create abundant extrinsic/intrinsic defects and additional active sites, reducing the K+ diffusion barrier and improving the capacitive-controlled capacity. The P-HCNFs delivers a high specific capacity of 310 mAh·g−1 at 0.1 A·g−1 with remarkable ultra-high-rate performance (140 mAh·g−1 at 50 A·g−1) and retains an impressive capacity retention of 87% after 10,000 cycles at 10 A·g−1. As expected, the as-assembled PIHCs present a high energy density (115.8 Wh·kg−1 at 378.0 W·kg−1) and excellent capacity retention of 91% after 20,000 cycles. This work not only shows great potential for utilizing heteroatom-doping and structural design strategies to boost potassium storage, but also paves the way for advancing the practicality of high-energy PIHCs devices.Graphical abstract

All-solid-state lithium-sulfur (Li-S) battery is regarded as next-generation high energy density and safety battery system. The key challenge is to develop a compatible high-performance solid-state electrolyte. Herein, a two birds with one stone strategy is proposed to simultaneously enhance Li+ conductivity and polysulfide adsorptivity of poly(ethylene oxide) (PEO)-based polymer electrolyte via the integration of Nb2CTx MXene. Moreover, the sheet size of Nb2CTx MXene is crucial for the enhancement of Li+ conductivity and polysulfide adsorptivity, attributing to the difference in a specific surface area related to the percolation effect. By tuning the sheet size of Nb2CTx MXene from 500–300 nm to below 100 nm, the ionic conductivity of the PEO electrolyte is increased to 2.62 × 10−4 S·cm−1 with improved Li+ transference number of 0.37 at 60 °C. Furthermore, theoretical calculation and X-ray photoelectron spectroscopy (XPS) conjointly prove that polysulfides could be effectively adsorbed by Nb2CTx nanosheets via forming Nb−S bonding to inhibit their shuttle in the PEO framework. As a result, the all-solid-state Li-S cell exhibits an initial capacity of 1149 mAh·g−1 at 0.5C and good cycling stability with 491 mAh·g−1 after 200 cycles. The results demonstrate the necessity of polysulfide inhibition and the application of Nb2CTx MXene in PEO-based electrolytes for all-solid-state Li-S batteries.Graphic Abstract

The dissolution performance of black aluminum dross (BAD) in cryolite electrolyte is key to its recovery by molten salt electrolysis. The stable operation of the electrolyzer depends mainly on the rapid dissolution of BAD in Na3AlF6-AlF3-Al2O3 electrolyte system. In this paper, the dissolution performance and behavior of BAD and its main components in the cryolite system were studied, and the saturation solubility of aluminum nitride in this system was determined. The dissolution performance of BAD in cryolite electrolyte before and after denitration was compared, and the effects of temperature, cryolite ratio, and the doping ratio of BAD and alumina on the dissolution rate were investigated. The obtained results showed that aluminum nitride was the main factor affecting the dissolution performance of BAD in the electrolyte. Aluminum nitride was partly converted to α-Al2O3 after addition to the electrolyte, and the converted α-Al2O3 was partially dissolved in the cryolite electrolyte, while the remaining precipitated and accumulated at the bottom with aluminum nitride. Aluminum nitride was almost insoluble in the cryolite electrolyte, with 0.0022% solubility. A higher proportion of α-Al2O3 in BAD was negatively influenced its solubility in the cryolite electrolyte. The dissolution rate of BAD in cryolite electrolytes was effectively improved by mixing BAD with γ-Al2O3.Graphical abstract

Herein, we successfully prepare highly dispersed and uniform small nano-size nickel nanoparticles embedded on core–shell carbon spheres by confined-deposition method. The mesoporous silica layer containing surfactant coated on the surface of the polymer sphere provides confined space and effectively controls the growth of nickel nanoparticles during pyrolysis. At the same time, the introduction of nickel species has an impact on structure of the obtained carbon spheres, and it can promote the deposition of carbon to realize the adjustment from hollow to core–shell and then to solid spheres. Owing to the uniform distribution of Ni nanoparticles with small size, mesoporous structure, N-doping groups, high specified surface areas, and core–shell structure, the obtained catalyst shows exciting ability for the production of CO by reduction of CO2 with a maximum CO Faradaic efficiency of 98%, indicating its promising prospect in electro-reduction of CO2.Graphical Abstract

In this paper, the metastable β TB8 titanium alloy with nanocrystalline α phase is achieved by electric pulse treatment. The morphology evolution and variant selection of nanocrystalline α phase in metastable β TB8 titanium alloy were investigated by using scanning electron microscope (SEM), electron backscattered diffraction (EBSD) and transmission electron microscope (TEM) analysis. The results indicated that the morphologies of the nanocrystalline α phase were mainly triangular clusters and needle-like at the pressure of 0 MPa. With increasing pressure from 20 to 50 MPa, the volume fraction of needle-like α phase decreased, and a large amount of V-shaped α phase formed in the interior of β grains. Based on the EBSD data, the parent β phase was reconstructed by MTEX software. In the interior of the β grains, 12 variants can form for the samples electric pulse treated at 0 and 20 MPa, while only 3 and 6 variants can form for the samples electric pulse treated at 30 and 50 MPa. In the grain boundary of the β grains, one or more grain boundary α variants can be generated for the samples electric pulse treated at different pressures as long as one of the neighbor β grains follows the Burgers orientation relationship.Graphical abstract

To obtain environmentally friendly, integrated and miniaturized gas sensors for the increasing request for the Internet of Things industry and other relative areas, the ultra-thin CoOx/ZnO heterogeneous film with active interfacial sites was in-situ deposited on micro-electro-mechanical systems (MEMS) as H2S sensor. Atomic layer deposition (ALD) was employed to in-situ fabricate the uniform ZnO thin film. ALD CoOx was deposited on ZnO surface to obtain CoOx/ZnO heterojunction and active interfacial sites. The ultra-thin film (20 nm) with 50 ALD CoOx decorated on 250 ALD ZnO displays excellent sensing performance, including very high response (4.45@200 × 10−9) and selectivity to H2S with a limit of detection (LOD) of 0.38 × 10−9, long-term sensing stability, high response/recovery performance (7.5 s/15.7 s) and mechanical strength at 230 °C. Reasons for the high sensing performance of CoOx/ZnO have been confirmed by series of characterizations and density functional theory (DFT) calculation. Heterojunction film thickness with Debye length, the oxygen vacancies and the synergistic effect of active interfacial sites are main reasons for the high sensing performance. The strategy by fabrication of CoOx/ZnO heterogeneous film within Debye length and employing synergistic effect of active interfacial sites offers a promising route for the design of environmentally friendly gas sensors. Furthermore, the ALD technique offers a facile in-situ strategy and high-throughput fabrication of MEMS gas sensors.Graphical Abstract

Polycrystalline Ni-rich layered oxide (LiNixCoyMnzO2 (NCM), x > 0.8) cathode material with high specific capacity and low cost is considered as one of the most promising candidate materials for lithium-ion batteries (LIBs). However, it suffers from severe structural and capacity degradation during practical cycling, especially under harsh operation condition (ultrahigh cutoff voltage and elevated temperature, etc.). One promising approach to mitigate these issues is to develop a single-crystal Ni-rich NCM cathode, which could enhance structural integrity and improve capacity retention, due to its robust and stable micro-sized primary particles. However, the improved cyclic stability comes at the expense of reversible capacity and rate capability, owing to the relatively low Li+ diffusion efficiency for its micron-sized primary particles. Moreover, the structural degradation and exacerbation of interfacial reactions for the Ni-rich NCM cathode under high-voltage (≥ 4.5 V) would quickly trigger the poor electrochemical performance, limiting its practical applications. Herein, LiNi0.827Co0.11Zr0.003Mn0.06O2 (Zr@SC-N83) cathode material was successfully synthesized via the in situ doping strategy. It could not only effectively maintain the reversibility of phase transition between H2 and H3 after long-term cycling at high voltage (4.6 V), but also enhance lithium-ion diffusion, thus improving the cycling performance and good rate performance for the Zr@SC-N83 cathode. As a result, 0.3 wt% Zr-doping cathode delivers an initial discharging capacity of 200.1 mAh·g−1 at 1.0C and at the high cutoff voltage of 4.6 V, exhibiting the satisfactory capacity retention of 85.5% after 100 cycles. It provides an effective route toward low-cost and higher energy density for lithium-ion batteries with Ni-rich cathode.Graphical Abstract

Fascinating with high specific capacity and moderate lithiation potential, SnOx-based materials have been intensively investigated as one of the most promising anodes for lithium-ion batteries. However, due to poor cycling stability, sluggish reaction kinetics, and limited electrochemical reaction reversibility, the development of SnOx-based anodes has been hindered. And the current preparation and modification routes for SnOx-based anodes lack direct and specific illustration. Herein, modification routes for SnOx-based anodes have been emphasized. Firstly, to provide more direct instructions, the tuning routes of morphological structure for SnOx-based electrodes (including slurry-based and self-supported) have been thoroughly discussed from the preparation perspective. Secondly, according to the properties of SnOx-based anodes, the phase structure design ideas have also been properly classified and organized for addressing chemical reaction kinetics or thermodynamic issues. Finally, for future-oriented studies, new insights into the development and commercialization prospects of SnOx-based anodes are also provided. This review, with comprehensive information on SnOx-based anodes, aims to bring more specific guidance and valuable inspiration for peer researchers who are promoting the application of SnOx-based materials for energy conversion and storage devicesGraphical Abstract

Electrochemical tests and surface analysis were applied to study the corrosion behavior and passive film characteristics of three-dimensional-printed NiTi shape memory alloys fabricated by laser-powder bed fusion (L-PBF) in artificial saliva at 37 °C. The passivity of L-PBF NiTi shows to be influenced by the process parameters and resulting morphological and physicochemical surface properties. The results show that the defects at the surface of L-PBF NiTi can promote the passivation rate in the early stages of exposure but a slowly formed passive film shows the best corrosion protection. The thickness of the passive film is positively correlated with its corrosion protective performance. The L-PBF NiTi alloy prepared at a linear energy density of 0.2 J·m−1 and volumetric energy density of 56 J·mm−3 shows the least defects and best corrosion protection. An outer Ti-rich and inner Ni-rich dense passive film could be also obtained showing higher corrosion resistance.Graphic Abstract

AbstractA study of the phase transformation process of a Fe-Ni-B-Si-P-Nb metallic glass using a suite of advanced characterization tools is reported. Transmission electron microscopy (TEM) and small angle neutron scattering (SANS) experiments show that the as-spun metallic glass ribbon has a dual-phase structure with bcc nanoclusters of a size of 2–3 nm. In situ high-energy X-ray diffraction (XRD) reveals a three-stage crystallization process when heating the metallic glass into supercooled liquid states. The isothermal annealing experiment shows the nanoclusters grow instantly without incubation. The easy formation and phase stability of the nanoclusters are due to the low interfacial energy between the amorphous matrix and clusters, as real space analysis shows that the nanoclusters and the amorphous matrix share similar short-to-medium-range orders. We further find that the dual-phase structure reduces local magneto-anisotropy and enhances effective magnetic permeability, resulting in an excellent stress-impedance effect without sacrificing coercivity. Our work sheds light on the structure-property engineering of soft magnetic metallic glasses and provides a foundation for developing novel magnetic functional materials with nanostructured dual-phases.Graphical Abstract

Zn3V2O8 was considered as a promising anode material for lithium-ion battery (LIB), because of its high theoretical specific capacity, environmental friendliness, and ease of availability. However, the large volume change and low electronic conductivity of Zn3V2O8 in repeated charge/discharge cycles have severely limited its applications. To solve the above issues, hierarchical Zn3V2O8 microspheres assembled by two-dimensional (2D) nanosheets were successfully synthesized, and carbon nanotubes (CNTs) were further introduced to cross-link the Zn3V2O8 microspheres. The interconnected nature of the three-dimensional (3D) conducting network and the special hierarchical morphology were beneficial for improving the stability and conductivity of the composite, leading to the reduction of the impedance and a significant improvement of the electrochemical performance. The reversible capacity of the as-prepared composite can achieve 1049.5 mAh·g−1 at a current density of 0.2 A·g−1 with a capacity retention of ~ 81% after 100 cycles. It is suggested that morphology modulation coupled with interconnecting CNT network is an effective method to boost the electrochemical performance of the anode materials for lithium-ion batteries.Graphical abstract

0.5 wt% Nb2O5 doped 0.12BiAlO3-0.88BaTiO3 (12BA5N) multilayer ceramic capacitor (MLCC-1) was prepared, which satisfied EIA X7R specification (where X is the minimum temperature, R is the percentage of capacitance variation limit) at 1 kHZ. The distribution of internal electric field under breakdown voltage was simulated by finite element method (FEM), indicating that the electric field strength increased significantly at the terminal of internal electrode. These areas may become the headstream of breakdown for MLCC-1 due to the shape mutation. In order to improve the breakdown performance of MLCC-1, it was optimized by 12BA5N + 2G green sheets (prepared by12BA5N ceramic powder with 2 wt% B-Al-Si glass additive), then MLCC-2 was obtained which satisfied EIA X8R specification. Its BDS rose from 20 to 29.4 kV·mm−1, and the electric field distribution of dielectric layer was also analyzed by FEM. Besides, it was also found that the grain size and the dielectric constants of “core” and “shell” parts for the 12BA5N + 2G dielectric layer both contributed to the enhanced BDS of MLCC-2 according to the simulation results from FEM.Graphical abstract

Film dielectric capacitors enabled with large breakdown field strength and high energy density play a key role for compact and integrated power systems. Nevertheless, the energy storage efficiency is always sacrificed as we tried to increase the energy density. This trade-off between energy density and efficiency means significant energy dissipation and thermal effects, which will lead to a deterioration of the reliability and lifetime of the dielectric capacitors. In the present work, we design a crystalline–amorphous structure based on BaTi0.5Hf0.5O3 films, in which the nano-sized crystalline BaTi0.5Hf0.5O3 matrix contributes to a relatively large polarization, while the amorphous phase is beneficial to the enhanced breakdown field strength and lowered polarization–electric field hysteresis. Thus, such structure simultaneously leads to a high energy storage efficiency of 90.6% and a relatively high energy density of 53 J·cm−3, as well as excellent antifatigue properties. This work provides a feasible route to realize outstanding energy storage performance in dielectric capacitors.Graphical abstract

Selenium (Se) is a promising cathode material for lithium batteries due to its high volumetric energy density (2528 Wh·L−1). However, its practical application is restricted by rapid capacity fading resulting from the shuttle effect and slow reaction kinetics. Herein, a N/Co co-doped three-dimensional porous carbon (Co-NC) is prepared and used as Se host for lithium–selenium batteries (LSeBs). Co-NC displays a high specific surface area of 1201 m2·g−1 which benefits from N and Co doping. The N and Co not only enhance the electrical conductivity of porous carbon but also possess an adsorption effect on polyselenide. Thus, Se/Co-NC electrode exhibits excellent cycling performance (a stable specific capacity of 480 mAh·g−1 after 200 cycles at 1.0C with a much low-capacity decay of 0.028% per cycle) and outstanding rate performance (a high specific capacity of 414 mAh·g−1 at 5.0C). This work inspires highly stable Se cathode design for LSeBs.Graphical abstract

Since the discovery of ferromagnetic morphotropic phase boundary (MPB) in 2010, the connotation and extension of MPB have been becoming more and more abundant. Over the last dozen years, much experimental work has been done to design magnetostrictive materials based on the MPB principle. However, due to the difficulty in direct experimental observations and the complexity of theoretical treatments, the insight into the microstructure property relationships and underlying mechanisms near the ferromagnetic MPB has not been fully revealed. Here, we have reviewed our recent computer simulation work about the super-magnetoelastic behavior near the critical region of several typical materials. Phase-field modeling and simulation are employed to explore the domain configuration and engineering in single crystals as well as the grain size effect in polycrystals. Besides, a general nano-embryonic mechanism for superelasticity is also introduced. Finally, some future perspectives and challenges are presented to stimulate a deeper consideration of the research paradigm between multiscale modeling and material development.Graphical Abstract