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Gradient boosting decision tree (GBDT) machine learning (ML) method was adopted for the first time to automatically recognize and conduct quantitative statistical analysis of boundaries in bainitic microstructure using electron back-scatter diffraction (EBSD) data. In spite of lack of large sets of EBSD data, we were successful in achieving the desired accuracy and accomplishing the objective of recognizing the boundaries. Compared with a low model accuracy of 40°) was ∼97 %, and block boundary was ∼96 %. The derived outcomes of ML were used to obtain insights into the ductile-to-brittle transition (DBTT) behavior. Interestingly, ML modeling approach suggested that DBTT was not determined by the density of high angle grain boundaries, but significantly influenced by the density of PAG and packet boundaries. The study underscores that ML has a great potential in detailed recognition of complex multi-hierarchical microstructure such as bainite and martensite and relates to material performance.

Here, the light-induced changes of the core antenna complex chlorophyll protein 43 (CP43) isolated from PSII of spinach were assessed using infrared and terahertz (THz) spectroscopy. We found that the collective vibrational modes at low frequencies and the secondary structures of CP43 were altered upon illumination. The helix changed more than any other secondary structure. CP43 is more easily damaged by illumination than PSII. Infrared and THz spectroscopy have different functions in protein studies. THz spectroscopy has potential in evaluating the stability of proteins.

Highly conductive cathode material with enhanced Na+ diffusion kinetics is of great importance in the exploration of sodium ion batteries. In this work, Na0.91MnO2 porous microcube which is coated with highly conductive polypyrrole (PPy) is obtained. The high Na content in the layered sodium manganate oxide brings about wider interlayer distance resulting in high capacity and electrochemical kinetics. The higher sodium content of Na0.91MO2 makes capacity increase up to 50 mAh g-1 compared with Na0.7MnO2.05. Furthermore, the well-designed combination between porous structure and conductive PPy coating exhibits fast ion/electron transfer inside the electrode and high cycling stability. The PPy coated Na0.91MnO2 delivers a high initial capacity of 208 mAh g-1, encouraging capacity retention and rate capability. Based on the porous Na0.91MnO2@PPy cathode, the sodium ion full cells with puffed millet porous carbon anode show remarkably stable cycling and high-rate performances.

Tin oxide (SnO2) has been widely used as an anode material for sodium-ion storage because of its high theoretical capacity. However, it suffers from large volume expansion and poor conductivity. To overcome these limitations, in this study, we have designed and prepared Mo-doped SnO2 nanoflake arrays anchored on carbon foam (Mo-SnO2@C-foam with 38.41 wt% SnO2 and 3.7 wt% Mo content) by a facile hydrothermal method. The carbon foam serves as a three-dimensional conductive network and a buffer skeleton, contributing to improved rate performance and cycling stability. In addition, Mo doping enhances the kinetics of sodium-ion transfer, and the interlaced SnO2 nanoflake arrays is beneficial to promote the conversion reactions during the charge/discharge process. The as-prepared composite with a unique structure demonstrate a high initial capacity of 1017.1 mAh g−1 at 0.1 A g−1, with a capacity retention over three times higher than that of the control sample (SnO2@C-foam) at 1 A g−1, indicating a remarkable rate performance.

The structure stability, diffusion behavior of interstitial hydrogen, and its influence on the elastic properties of stoichiometric ZrC bulk are investigated by first-principles calculations. The interstitial hydrogen in stoichiometric ZrC bulk prefers to be trapped by the C atom with C-H distance of 1.15 A, and its formation energy is 1.30 eV after ZPE correction. The interstitial hydrogen promotes the formation of Zr/C vacancy in ZrC bulk due to the electron localization effects and the effect on the C vacancy is more significant. A new energetically favorable diffusion path of hydrogen in ZrC bulk is predicted as from one center C-H site in the Zr/C cube to the other neighboring one by climbing the metastable Zr/C cubic center site with an energy barrier of 0.64 eV, and then followed by twice rotations around the nearest neighboring C atom with an energy barrier of 0.26 eV. A high hydrogen resistance can be expected on the ZrC ceramic due to the extremely low hydrogen diffusivity and the insignificant effects of hydrogen on the elastic properties.

A compositive synthesis of gel polymer electrolytes by blending poly(propylene carbonate) (PPC) into poly(vinylidene fluoride-hexafluoropropylene) (PVDF-HFP) as a polymer host is proposed. The blending polymer is produced by a facile solution casting method and ester groups of PPC are successful introduced into PVDF-HFP. The gel polymer electrolyte displays an excellent ion conductivity of 1.18 × 10−3 S cm−1, broad electrochemical window up to 4.8 V (vs. Li/Li+) and outstanding electrochemical stability within rechargeable lithium batteries at room temperature. The improvement of ion conductivity is attributed to the decrease of polymer crystallizability and the increase of micro pores. The strategy of blending is promising for the modification of PVDF-HFP electrolyte and foreground application in next-generation solid energy conversion devices.

A UV-light polymerized three-dimensional (3D) network gel polymer electrolyte (GPE) is designed and fabricated for solid-state lithium-sulfur (Li-S) batteries. The GPE exhibits wide electrochemical window up to 5.05 V (vs. Li+/Li), outstanding thermostability and mechanical property. Besides, the GPE effectively suppresses the extension of lithium dendrite and the electron-donating groups in GPE inhibit the shuttle of lithium polysulfides. The assembled solid-state Li-S batteries with the 3D network GPE show high specific capacity retention of 69.1% after 300 cycles at 0.5 C. With the consideration of these, the GPE in this report undoubtedly provides an effective technique to design high performance solid-state Li-S batteries.

The poor interfacial contact between electrode materials and electrolyte has become a major obstacle to the development and application of solid-state batteries. In this work, we report a facile method to realize interfacial modification with the help of in-situ ultraviolet solidified gel polymer electrolyte, which is completely compatible with commercial LiFePO4 and cellulose membrane forming stable composite cathode and cellulose membrane-gel polymer electrolyte. Two intimate interfaces between LiFePO4 and gel polymer electrolyte as well as composite cathode and cellulose membrane-based composite electrolyte are achieved to facilitate fast transfer of lithium ions at the interface. The assembled solid-state cell exhibits lower interfacial resistance, reduced polarization, higher rate capability, and more stable cycling performance than other routine counterparts. This work provides a new way for fabrication of novel advanced solid-state electrolytes and electrodes for applications in solid-state batteries.

All-solid-state lithium batteries (ASSLIBs) employed inorganic solid electrolytes are attracting increasing interest for electrochemical energy storage devices due to their advantages of high safety, high energy density, wide operating temperature range and long cycle life. However, the large interfacial resistance originated from the insufficient solid-solid contact at electrolyte/electrode interface hinders the development of all-solid-state batteries. In addition, the interfacial compatibility and stability also greatly affect the electrochemical performance of batteries. This review summarizes the challenges and progress for the studies of interface problems in ASSLIBs. Based on the review, we attempt to propose alternative approaches to the issue and prospective developments of ASSLIBs.

High-quality solid electrolyte is essential for the growing need of lithium ion batteries. Herein, we report a novel organic-inorganic composite electrolyte based on Li7La3Zr2O12 ceramic powder incorporated into PVDF-HFP through a simple combined method. At room temperature, the composite polymer electrolyte (CPE) possesses a good ionic transmission improvement of 3.71 × 10−4 S cm−1. The CPE behaves a fine lithium ion transference number of 0.58 and an electrochemical window of up to 4.65 V. CPEs display meliorative electrochemical stability compared to pure PVDF-HFP electrolyte. The cathode presents an excellent initial discharge capacity of 163.1 mAh g−1 at 0.2 C in Li/CPE/LiFePO4 cell. The cell with CPE displays much better capacity retention than that with pure PVDF-HFP electrolyte. The Li7La3Zr2O12 modified PVDF-HFP is a promising electrolyte for lithium ion batteries.

Large interfacial resistance between electrode and electrolyte limits the development of high-performance all-solid-state batteries. Herein we report a uniform coating of Li7P3S11 solid electrolyte on MoS2 to form a MoS2/Li7P3S11 composite electrode for all-solid-state lithium ion batteries. The as-synthesized Li7P3S11 processes a high ionic of 2.0 mS cm−1 at room temperature. Due to homogeneous union and reduced interfacial resistance, the assembled all-solid-state batteries with the MoS2/Li7P3S11 composite electrode exhibit higher reversible capacity of 547.1 mAh g−1 at 0.1 C and better cycling stability than the counterpart based on untreated MoS2. Our study provides a new reference for design/fabrication of advanced electrode materials for high-performance all-solid-state batteries.

Lithium metal has always been considered as a “Holy Grail” of anode materials for high-energy-density batteries owing to its extremely high theoretical gravimetric capacity of 3860 mAh g −1 and the lowest electrochemical potential of −3.04 V. Unfortunately, huge challenges including unlimited dendrite growth and complex interfacial reaction accompanied with relatively low Coulombic efficiency have extremely restricted its practical applications for decades. In this review, we discuss recently exciting achievements in modifying Li metal anodes, particularly regarding porous structure design, surface modification, heterogeneous seed strategy, potential substitutes including Li powder, and pre-lithiated composite. Although each improvement method has its own advantage, we believe appropriate combination of them will yield more promising results. Finally, we discuss core issues and potential opportunities of Li metal anode, expecting to shed new light on future research in this field.

High-performance lithium ion batteries (LIBs) with high energy/power density are always the persistent pursuit of people. High-quality anode is the key point for the performance improvement of LIBs. In this work, a facile combined strategy is proposed to construct integrated TNO/AOSC electrode, in which Aspergillus Oryzae Spore Carbon (AOSC) conductive matrix is employed to hold Ti2Nb10O29 (TNO) nanoparticles. The TNO/AOSC not only shortens electron/ion transfer pathway on account of the nanostructure of TNO, but also provides better chemical stability from AOSC skeleton. Accordingly, the preeminent rate capacity (135.2 mA h g−1 at 10C) and relatively superior cycle stability (a capacity of 149.8 mA h g−1 after 200 cycles at 1C) are obtained for the TNO/AOSC, much better than TNO counterpart. The superior performance of the TNO/AOSC can be ascribed to the beneficial synergistic factors on enhanced electronic conductivity and solider structure from AOSC substrate. This intriguing design strategy may trigger interest for design of other high-quality electrodes in LIBs.

In this work, IGZO ink was prepared by dissolving gallium chloride, indium chloride, zinc acetate dihydrate and monoethanolamine (MEA) in 2-methoxyethanol. Five types of IGZO ink were prepared with different molar ratios of In:Ga:Zn: A(10:1:10), B(10:3:10), C(10:5:10), D(10:7:10), E(10:9:10). Based on the above-prepared ink, IGZO films were printed by a FujiFilm Dimatix printer (DMP-2831) on the glass, and then annealed with differenYut temperatures. The film samples with different Ga concentrations and annealing temperatures were investigated to study the uniformity, optical transmittance and electron mobility.

The ZrN/Zr/a-C multilayered coatings were deposited onto Ti6Al4V and Si substrates using a closed field unbalanced magnetron sputtering. The morphology and microstructure of the multilayers were performed by scanning electron microscopy (SEM), atomic force microscopy (AFM) and transmission electron microscopy (TEM). The multilayer consists of a-C layers, Zr layers and ZrN layers. The Zr interlayers can improve the weak adhesion between a-C layers and ZrN layers. The multilayer exhibits a low residual stress of − 0.5 GPa and a hardness of 18.7 GPa. The tribological properties were evaluated by a ball-on-disk tribometer. The friction coefficient and wear rate of the multilayer in fetal bovine serum (FBS) kept very low values during sliding at an applied load of 2 N, which indicated excellent long-term wear resistance. What is more, the multilayer also presented a low wear rate in FBS even at a high applied load of 10 N. Additionally, the corrosion resistance of Ti6Al4V in Hank's solution is significantly improved by the multilayer. This study demonstrates that the ZrN/Zr/a-C multilayer exhibits excellent performance including low residual stress, high corrosion resistance as well as good bio-tribological properties and it is proper to protect Ti6Al4V alloy.

Biomedical Ti6Al4V alloy exhibits excellent mechanical and anti-corrosion properties but poor wear resistance. In order to improve the combination performance of Ti6Al4V alloy, Zr-doped graphite-like carbon (GLC) nanomultilayer and nanocomposite coatings are deposited by magnetron sputtering. The microstructures of the coatings are characterized by transmission electron microscopy (TEM) and Raman spectroscopy. The Zr-doped GLC nanomultilayer shows low friction coefficient and wear rate at applied loads of 1 N and 3 N in Hank's solution. In addition, both the Zr-doped GLC nanomultilayer and nanocomposite coatings present high corrosion resistance, which results from the corrosion-resistant GLC and zirconium oxide. Compared to the Zr-doped GLC nanocomposite, the nanomultilayer is more promising in the applications under simultaneously tribological and corrosive conditions.

Ultra-high purity CrO 2 was prepared by decomposing CrO 3 in O 2 with gas pressures up to 40 MPa, which were maintained throughout the decomposition process of CrO 3 to prevent the formation of any other phases of chromium oxides. Our method is different from the traditional methods that start from or under ambient pressures. The high oxygen pressure makes the meta-stable CrO 2 stable from the initial stage of preparation. As a result, the purity of the as-prepared CrO 2 is improved, and this has been further proved by the highest magnetization of the samples. The as-prepared CrO 2 particles show very large grains with flat surfaces, octagonal cross-section, and straight edges, owing to the high mobility of Cr ions in CrO 2 at temperatures above its melting point. The lattice parameters of CrO 2 are a = 4.4176 A and c = 2.9144 A. The maximum value of the magnetic entropy change of the high purity CrO 2 particles is ∼2.83 J/kg·K for an applied field of 1.5 T. The preparation of pure CrO 2 is important for studying its intrinsic properties and for applications in spintronic devices.

Amorphous carbon (a-C) film is deposited with a gradient designed bias voltage on the ultrahigh molecular weight polyethylene (UHMWPE) substrates and Si3N4 balls via a closed field unbalanced magnetron sputtering. The designed bias voltage continuously increases from − 40 V to − 80 V with two different increasing rate. The film with a thickness of approximately 1000 nm is made up of equiaxed grains with size of around 20 nm. Nanoindentation tests show that the hardness of the UHMWPE increases from 44 MPa to 2.16 GPa after deposition of a-C film with gradient designed bias voltage. The wear rate and friction coefficient of the a-C film sliding against a-C films coated on Si3N4 balls is tested in air and Hank's solution by means of a reciprocating tribometer. The a-C film deposited with gradient bias voltage exhibits superior adhesion and tribological performance, compared with those deposited with balanced bias voltage. The a-C film wearing against Si3N4 balls with a-C film coating shows a lower wear rate, compared with a-C films wearing against uncoated balls, decreasing from 1.95 × 10− 15 m3 N− 1 m− 1 to 1.23 × 10− 15 m3 N− 1 m− 1. There is a further enhancement of the anti-wear performance in Hank's solution.

Improving the insulating nature of sulfur and retaining the soluble polysulfides in sulfur cathodes are crucial for realizing the practical application of lithium–sulfur batteries (LSBs). Biomass-based carbon is becoming increasingly popular for fabricating economical and efficient cathodes for LSBs owing to its unique structure. Herein, we report a facile strategy to transform bovine bone with an organic–inorganic structure into cellular hierarchical porous carbon via carbonization and KOH activation, followed by CoS2 modification through hydrothermal treatment. The synthesized composite can load abundant sulfur and produce a dual effect of “physical confinement and chemical entrapment” on polysulfides. The conductive carbon frame with the developed porous structure provides adequate space to accommodate sulfur and physically suppress the shuttle effect of polysulfides. The embedded half-metallic CoS2 sites can chemically anchor the polysulfides and enhance the electrochemical reaction activity as well. Owing to the multifunctional structure and dual restraint effect, the designed electrode exhibits enhanced electrochemical properties including high initial capacity (1230.9 mAh g−1 at 0.2 C), improved cycling stability and enhanced rate capability.

In this work, multilayer composites composed of ethylene-propylene-diene monomer (EPDM) foams and EPDM perforated plates were proposed to improve sound absorption properties at medium and low frequency. Models of composites with variable section cavities were designed and explored the influence of structural parameters on sound absorption coefficient. Numeral calculations results showed that the sound absorption curves of multilayer composites usually have two peaks in 300–1300 Hz. Compared with the other, the composite composed of one perforated board with variable section cavities and two foams (VFF) shows best sound absorption capacities in low frequency. Two optimization algorithms: artificial fish swarm algorithm (AFSA) and improved particle swarm optimization (I-PSO) were presented to optimize structural parameters of VFF. It is found that the optimization results of I-PSO are better that of AFSA for improving the absorption properties at low medium and frequency. This work provide a simple method and a new idea to improve sound absorption properties of multilayer composites.

Aqueous zinc-ion battery is a low-cost, non-toxic, and high-safety energy storage system, which has received extensive attention in recent years. However, the Zn anode with high theoretical capacity often suffers from severe corrosion and dendrite growth during the Zn plating/stripping process, leading to severe polarization and eventually short circuits. These knotty problems severely impede further practical applications of Zn-based batteries. Herein, a robust and homogeneous metallic tin (Sn) coating is in situ built on the surface of Zn to form Zn|Sn by a facile chemical vapor deposition method to enhance reaction reversibility. The as-prepared Sn coating not only affords more robust nucleation sites of Zn and higher hydrogen evolution reaction potential, but also effectively decreases the nucleation overpotential of Zn. Accordingly, the symmetric cells with Zn|Sn anode can stably maintain an extremely low-voltage hysteresis (50 mV) in a 500 h of plating/stripping cycles. Even at a high current density of 50 mA cm−2, the symmetric Zn|Sn cell still can operate well for 50 h. Moreover, this stable Zn|Sn anode also enables a full Zn-ion battery with outstanding rate and cyclic stability.

Amorphous carbon (a-C) and Ta- or Ti-doped a-C multilayer films are deposited onto Ti6Al4V alloy by an industrial closed field unbalanced magnetron sputtering. The corrosion and tribocorrosion performances of these films are investigated in Hank's solution at 37 °C. The a-C film exhibits enhanced wear and corrosion resistance compared with the bare Ti6Al4V alloy, but the cracks propagate during the tribocorrosion process, which leads to serious breakage. Interestingly, the tribocorrosion resistance of a-C film is improved by introducing Ta- or Ti-doped multilayered structure. The high mechanical properties (high hardness and low residual stress), good corrosion, and wear resistance of Ta- and Ti-doped a-C multilayer films make them excellent protective materials for artificial joints.

Integral construction of lithium sulfide (Li 2 S) cathode is indispensable and vital for developing high-performance lithium-sulfur (Li-S) batteries. Herein we have demonstrated a facile strategy for fabricating free-standing carbon paper supported Li 2 S@C (P-Li 2 S@C) integrated cathode. The P-Li 2 S@C cathode is synthesized through simple pyrolysis of low-cost lithium sulfate (Li 2 SO 4 ) and chitosan, and embedded in the double carbon matrixes with carbon paper support and outer CVD-carbon layer. Li 2 S nanoparticles are homogeneously dispersed in the above designed double carbon matrixes. The P-Li 2 S@C cathode exhibits an initial discharge capacity of 820 mAh g −1 at 0.1 C and still maintains 430 mAh g −1 after 100 cycles, superior to the P-Li 2 S counterpart (480 mAh g −1 at 0.1 C and 150 mAh g −1 after 100 cycles). Our research verifies the effectiveness of double carbon modification on the Li 2 S, especially, the outer carbon coating not only improves the electrical conductivity of electrode, but also further prohibits the “shuttle effect” of polysulfides.

To meet the requirements for high-rate battery with desirable performance, a self-supported Ni 2 P@Ni sponge electrode is synthesized via simple steps, in which the Ni sponge substrate is synthesized by a one-pot hydrothermal method and the Ni 2 P nanosheets grown on the novel substrate are converted from Ni(OH) 2 via a phosphorization reaction. This hybrid composite combines the 3D porous structure of Ni sponge and high capacity of Ni 2 P nanosheets, which exhibits lightweight, flexible and highly-conductive properties, resulting in an excellent specific capacity of 430.3 mAh g −1 at a current density of 1 A g −1 and remaining as high as 77.0% capacity even at 40 A g −1 . More importantly, the Ni 2 P@Ni sponge//C cell exhibits the maximum energy density of 182.1 W h kg −1 at a power density of 205 W kg −1 along with superior capacity retention of 85.2% after 3000 cycles. It is suggested that the Ni 2 P nanosheet@ Ni sponge composite is a promising electrode material for high-rate batteries.

To meet the design requirements for high-rate battery electrodes, self-supporting hierarchical rGO@Ni nanosheet@Co3O4 nanowire array film with light weight is synthesized via a series of controllable fabrication processes. Due to modifying the highly conductive nickel nanosheets onto the surface of rGO film, the energy storage performance of this hybrid film is enhanced, especially in rate capability. The whole high-rate battery, which is fabricated by using this film as the positive electrode, manifests the maximum energy density of 20.3 Wh kg−1 at a power density of 326 W kg−1 along with excellent capacity retention of 81.4% after 5000 cycles. Therefore, the rGO-Ni-Co3O4 hybrid film is a promising electrode material for flexible long-life cycling high-rate batteries.

Surface conductive engineering on Li 2 S is critical for construction of advanced cathodes of lithium-sulfur batteries. Herein, we construct a high-performance Li 2 S-based composite cathode with the help of three-dimensional reduced graphene oxide (3D-rGO) network and outer carbon coating. Typically, the Li 2 S@C particles are uniformly embedded into 3D-rGO to form a binder-free 3D-rGO-Li 2 S@C cathode by the combination of a liquid solution-evaporation coating and PVP (Polyvinyl Pyrrolidone) carbonization. The 3D-rGO-Li 2 S@C cathode exhibits a high initial discharge capacity of 856 mAh g −1 at 0.1C, superior cycling stability with a capacity of 388.4 mAh g −1 after 200 cycles at 1C, corresponding to a low capacity fading rate. It is demonstrated that the outer conductive coating is effective and necessary for electrochemical enhancement of Li 2 S cathodes by improving electrical conductivity and prohibiting polysulfide from shuttling during cycling.

A novel electrocatalyst for methanol oxidation reaction in alkaline medium is elaborately fabricated by a sponge-template method involving an electroless plating of amorphous Ni–P on sponge and the following annealing process at 500 °C in air. The electrocatalyst is characterized by NiO nanoparticle/nanoflake grown on the Ni–P alloy tube. The vital annealing process aims to remove templates, crystallize Ni–P, and generate NiO nanostructures on the outside surface of Ni–P tubes, thus leading to the final structure of NiO/Ni–P composites. The tubular Ni–P framework surface is decorated with microspherical NiO (EP-M) or nanoflake NiO (EP-F), which strongly depends on the electroless plating time. For comparison, porous NiO nanoflakes are also synthesized by chemical bath deposition. The EP-M containing ∼83.8 wt.% NiO and ∼16.2 wt.% Ni–P has the largest BET surface area of 210.03 m 2 g −1 among the three samples. Moreover, the EP-M exhibits a high current density (∼467 A g −1 ) and long-term chronoamperometry stability (≥20,000 s) toward methanol oxidation in alkaline solution. The improved catalytic activity of the composite catalyst might be attributed to the strong electronic interaction between NiO and Ni–P as revealed by X-ray photoelectron spectroscopy.

A unique MoS 2 -based composite composed of MoS 2 nanosheets wrapped by a conductive polypyrrole (PPY) layer and closely incorporated within reduced graphene oxide (rGO) nanosheets is prepared by all-solution method. As a free-binder electrode for lithium-ion batteries, the ternary electrode delivers an initial discharge capacity of 1428 mAh g −1 , maintains 1070 mAh g −1 after 400 cycles at a current density of 200 mA g −1 , and also exhibits superior rate capacity of 600 mAh g −1 at a high current density of 2000 A g −1 . The enhanced electrochemical performance is attributed to the advantageous combination of the 3D hierarchically rGO skeleton and in-situ formed conductive PPY coating. This design route represents a new direction for high-performance lithium ion batteries and related energy storage application with advanced nanostructured materials.

Metal-doping is considered to be an effective way for construction of advanced semiconducting metal oxides with tailored physicochemical properties. Herein, Mo-doped WO3 nanowire arrays are rationally fabricated by a sulfate-assisted hydrothermal method. Compared to the pure WO3, the optimized Mo-doped WO3 nanowire arrays exhibit improved electrochromic properties with fast switching speed (3.2 s and 2.6 s for coloration and bleaching, respectively), significant optical modulation (56.7% at 750 nm, 83.0% at 1600 nm and 48.5% at 10 μm), high coloration efficiency (123.5 cm2 C−1) and excellent cycling stability. In addition, as a proof of concept, the Mo-doped WO3 nanowire arrays are demonstrated with electrochemical energy storage monitored by the electrochromism. This electrode design protocol can provide an alternative way for developing high-performance active materials for bi-functional electrochromic batteries.

An amorphous carbon (a-C) film is deposited on the plasma-treated UHMWPE substrate using a closed field unbalanced magnetron sputtering to improve its tribological properties. During the plasma treatment period, a transition layer is prepared by high energy ion bombardment at a bias voltage of −500 V to enhance the adhesion between the a-C film and the substrate. The mechanical and tribological properties of the a-C film were evaluated by nano-indentation and ball-on-disk tribometer. After deposition of a-C film with a thickness 900 nm, the nano-hardness of UHMWPE significantly increases from 47 MPa to 720 MPa and the wear rate decreases from 9.82 × 10 −15 m 3 N −1 m −1 to 4.78 × 10 −15 m 3 N −1 m −1 in bovine calf serum solution. The formation of the transition layer is believed to be the reason why the vertical adhesion between the a-C film and the UHMWPE substrate is enhanced.

In this study, highly crystallized hexagonal prism-like ZnO nanorods with planar tips and pyramid tips were successfully fabricated by hydrothermal method. The morphology and structure of samples were characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), energy dispersive spectrometer (EDS), Brunauer–Emmett–Teller (BET), scanning electron microscope (SEM) and transmission electron microscope (TEM). XRD and XPS analyses indicate Cr3+ ions are successfully doped into the ZnO lattice. In hydrothermal process, Cr ions replace the Zn sites and activate the ±{10 1 ¯ 1} crystal facets. Thus the morphology of ZnO is hexagonal prisms with planar tips, while the morphology of Cr doped ZnO is hexagonal prisms with pyramid tips. Sensing behavior of the sensors is also investigated. The response of Cr–ZnO sensor is 104 to 100 ppm acetone at 300 °C, which is four times higher than that of ZnO sensor. Improved response and selectivity of the sensor is attributed to the increase of electron concentration, which is optimized by Cr doping.

A facile one-pot solvothermal method is proposed to fabricate a new series of Ni-Co-P-O compound-based electrocatalysts for methanol oxidation in alkaline environment. It is found that the chemical composition, surface morphology, as well as the crystallographic structure of the final Ni-Co-P-O composites are largely depends on the Co 2+ /Ni 2+ molar ratios in the reaction system. The sample of NiCoPO-2 possessing an urchin-like architecture and a hybrid composition of nano-scaled Ni/Co phosphides and phosphates was produced at a Co 2+ /Ni 2+ molar ratio of 0.18. A larger specific surface area of 540.5 m 2 g −1 and a bimodal pore size distribution are found in the NiCoPO-2 sample. As a potential catalyst, the NiCoPO-2 delivers a highest oxidation current density (∼1567 A g −1 ) and a good durability (≥20000 s) toward the methanol electrooxidation reaction. The superior catalytic performance of the NiCoPO-2 catalyst should be attributed to its unique microstructure and compositions. It is also supposed that the formation of electron tunneling junctions between the metal phosphides and phosphates could provide new channels for facilitating electron transfer throughout the composite electrocatalysts.

The flowerlike Sn doped ZnO nanostructures were synthesized by a cetyltrimethylammonium bromide (CTAB)-assisted hydrothermal process at low temperature (150 °C). The morphology and structure of sample were characterized by XRD, EDS, XPS, SEM and TEM analysis. The results indicate that the sample is well crystallized wurtzite hexagonal phase of ZnO, and preferentially grows up along [0001] direction. The possible formation mechanism of flowerlike ZnO nanostructures is proposed. Moreover, the sensor based on flowerlike ZnO nanostructures exhibits enhanced sensing performances to acetone at 300 °C. The response is up to 600 when the sensor is exposed to 100 ppm acetone. The response and recovery times are about 24 and 8 s, respectively. These results demonstrate that the Sn doped ZnO nanoflowers can be used as the sensing materials for fabricating high performance acetone sensor.

The structure stability, hydrogen trapping behaviour, and adhesion properties of the Zr(0001) ZrC(100) interface are investigated by first-principle calculations. Periodically distributed distortion and stress-relaxed regions with lengths of 16.6 A are formed to relax the lattice mismatch at the Zr(0001) ZrC(100) interface. Homogeneous covalent 3Zr C bonds are formed in the distortion region. The interfacial sinking effect exists only in the interface stress-relaxed region where the interstitial hydrogen has a considerably lower formation energy of −0.61 eV after the zero-point energy correction, than those in the interface distortion region, Zr, and ZrC bulk of 0.95, −0.10, and 1.30 eV, respectively. After the interstitial sites in the interface stress-relaxed region are fully occupied by hydrogen, the interface energy is significantly reduced from 2.34 to 1.52 J/m2. The work of separation Wsep along the interface is approximately 3.78–3.91 J/m2, while the brittle fracture of the Zr(0001) ZrC(100) interface always occurs at the Zr matrix (along the Zr1 layer) with the lowest Wsep of 3.18–2.95 J/m2. Hydrogen-induced electron localisation exists at the interface, which reduces the interface structure stability. In addition, a hydrogen passivation layer forms owing to the formation of Zr H and C H bonds at the interface.

Exploring high performance cathode materials is of great means for the development of bi-functional electrochromic energy storage devices. Herein, Nb-doped WO3 mesoporous films as integrated high-quality cathode are successfully constructed via a facile sol-gel method. Chemical state and crystallinity of the WO3 based films are significantly influenced by doping concentration. Compared with the pure WO3, the optimal Nb-doped film shows improved optical-electrochemical properties with high specific capacity (74.4 mAh g−1 at 2 A g−1), excellent high-rate capability, large optical contrast (61.7% at 633 nm), and ultra-fast switching speed (3.6 s and 2.1 s for coloring and bleaching process, respectively). These positive features suggest the potential application of Nb-doped WO3 mesoporous cathode. Our research paves the way for the development of multifunctional photoelectrochemical energy devices.

Epitaxial Fe $[ 0.25 +\mathrm {x}]$ Pt[0.75 – x] layers can be either antiferromagnetic (AF) or ferromagnetic (FM) depending on the degree of chemical ordering controlled by the deposition temperature. Our neutron diffraction studies were the first to study AF phase transitions in these thin films [1] and we have also shown using PNR that a mixed AF-FM film is exchange biased with itself [2]. In AF-FM exchange-biased superlattices with a modulated chemical order parameter, PNR shows the magnetization can be modulated through the film thickness with no composition modulations [3]. Our recent results reveal that He+ ion bombardment and annealing can be applied toward controlling magnetic phases in epitaxial Fe[0.25]Pt[0.75] layers [4].

The construction of advanced cathode materials is indispensable and vital for developing high-performance lithium–sulfur batteries. Herein, we develop a facile in-situ route to synthesize three-dimensional reduced graphene oxide supported Li 2 S/carbon composite (3D-rGO-Li 2 S/C). The Li 2 S/C nanoparticles are intimately anchored on the surface of 3D-rGO forming an integrated 3D porous composite. Due to the improved conductivity and reduced polysulfide dissolution, the 3D-rGO-Li 2 S/C cathode exhibits enhanced electrochemical performances with a high initial capacity of 819 mAh g −1 at 0.1C, as well as good cycling stability with a capacity retention of 415 mAh g −1 after 100 cycles at 1C. The integrated 3D conductive network is responsible for the enhancement of the electrochemical properties by providing fast ion/electron transfer and high mechanical stability.

Scrupulous design and fabrication of advanced anode materials are of great importance for developing high-performance lithium ion batteries. Herein, we report a facile strategy for construction of free-standing and free-binder 3D porous carbon coated MoS 2 /nitrogen-doped graphene (C-MoS 2 /N-G) integrated electrode via a hydrothermal-induced self-assembly process. The preformed carbon coated MoS 2 is strongly anchored on the porous nitrogen-doped graphene aerogel architecture. As an anode for lithium ion batteries, the C-MoS 2 /N-G electrode delivers a high first discharge capacity of 1600 mAh g −1 and maintains 900 mAh g −1 after 500 cycles at a current density of 200 mA g −1 . Impressively, superior high-rate capability is achieved for the C-MoS 2 /N-G with a reversible capacity of 500 mAh g −1 at a high current density of 4000 mA g −1 . Furthermore, the lithium storage mechanism of the obtained integrated electrode is investigated by ex-situ X-ray photoelectron spectroscopy and transmission electron microscopy in detail.

Construction of high-capacity anode is highly important for the development of next-generation high-performance lithium ion batteries (LIBs). Herein we fabricate Si/Ag nanowires/reduced graphene oxide (Si/Ag NWs/rGO) integrated composite film by introducing binary conductive networks (Ag NWs and rGO) into Si active materials with the help of a facile vacuum-filtration method. Active Si nanoparticles are homogeneously encapsulated by binary Ag NWs-rGO conductive network, in which Ag NWs are interwoven among the rGO sheets. The electrochemical properties of the integrated Si/Ag NWs/rGO composite film are thoroughly characterized as anode of LIBs. Compared to the Si/rGO composite film, the integrated Si/Ag NWs/rGO composite film exhibits enhanced electrochemical performances with higher capacity, better high-rate capability and cycling stability (1269 mAh g −1 at 50 mA g −1 up to 50 cycles). The binary conductive network plays a positive role in the enhancement of performance due to its faster ion/electron transfer, and better anti-structure degradation caused by volume expansion during the cycling process.

Adsorption is often time consuming due to slow diffusion kinetic. Sizing he adsorbent down might help to accelerate adsorption. For CoFe spinel oxide, a magnetically separable adsorbent, the preparation of nanosheets faces many challenges including phase separation, grain growth and difficulty in preparing two-dimensional materials. In this work, we prepared porous CoFe oxide nanosheet with chemical formula of Co 2.698 Fe 0.302 O 4 through topochemical transformation of a CoFe precursor, which has a layered double hydroxide (LDH) analogue structure and a large interlayer spacing. The LDH precursor was synthesized from a cheap deep eutectic solvent (DES) system. The calcined Co 2.698 Fe 0.302 O 4 has small grain size (10–20 nm), nanosheet morphology, and porous structure, which contribute to a large specific surface area of 79.5 m 2 g −1 . The Co 2.698 Fe 0.302 O 4 nanosheets show fast removal ability and good adsorption capacity for both organic waste (305 mg g −1 in 5 min for Congo red) and toxic heavy metal ion (5.27 mg g −1 in 30 min for Cr (VI)). Furthermore, the Co 2.698 Fe 0.302 O 4 can be separated magnetically. Considering the precursor can be prepared through a fast, simple, surfactant-free and high-yield synthetic strategy, this work should have practical significance in fabricating adsorbents.

a-C/a-C:Ti multilayer films were deposited on medical Ti6Al4V alloy using a closed field unbalanced magnetron sputtering system with various substrate bias duty cycle. The tribological and corrosion behaviors of the multilayer films in Hank's solution were evaluated by a ball-on-disk tribometer and an electrochemical workshop. The duty cycle has a significant effect on the bonding structure, and mechanical and tribological properties of the films. The polarization resistance of the films on Ti alloy is approximately ten times more than that of Ti6Al4V which indicates that higher corrosion resistance can be achieved in Hank's solution at 37 °C. However, the polarization resistance and corrosion current do not change so much with the variation of duty cycle, implying that its influence on corrosion behavior of these a-C/a-C:Ti multilayer films is not so obvious.

The morphology evolution and hygroscopicity reduction of Y2Mo3O12 crystal are investigated by introducing (LiMg)3+. With increasing the content of (LiMg)3+, the hygroscopicity of Y2Mo3O12 is reduced obviously depending on the XRD, Raman and DSC/TG results, and the morphology of Y2Mo3O12 transforms remarkably from amorphous crystal to octahedra and then rod. The results suggest the effects of (LiMg)3+ on repelling water molecules and improving the growth of Y2Mo3O12 crystal, which could be a reflection of the decrease of micro-channels in the structure. Some (LiMg)3+ substitute Y3+ in Y2Mo3O12 to form solid solutions of (LiMg)2−xYxMo3O12 with octahedra and then rod, and excess (LiMg)3+ leads to the formation of (LiMg)2Mo3O12 due to the difficulty in substituting Y3+ with (LiMg)3+. The substitution of Y3+ for (LiMg)3+ reduces the thermal expansion coefficient of Li-ion battery material of (LiMg)2Mo3O12.

A novel 2Li3V2(PO4)3·LiV3O8 composite with short rod and thin plate shapes is synthesized through sol–gel method followed by hydrothermal and solid–state reaction. LiV3O8 is used as an additive to improve the capacity of Li3V2(PO4)3. In the composite cathode, active impurity phase Li0.3V2O5 is also present, which has little impact on the whole electrochemical properties. The 2Li3V2(PO4)3·LiV3O8 composite delivers a high initial capacity of 162.8 mAh g−1 at a current density of 100 mA g−1 in the voltage range of 2.0–4.3 V. Furthermore, the composite with high crystallinity also shows high electrochemical reversibility and good rate capability. The diffusion coefficient of Li ions in the composite is in the range of 10−11–10−9 cm2 s−1 obtained from galvanostatic intermittent titration technique.

A novel 0.6Li 3 V 2 (PO 4 ) 3 ·0.4Li–V–O composite cathode material is synthesized by sol-gel method followed by solvothermal and solid state reaction. The morphology and structure of the composite are characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD) and X-ray photo-electron spectroscopy (XPS). The composite particles are well-crystallized and present uniform nanoplate alike. Except Li 3 V 2 (PO 4 ) 3 phase, LiV 2 O 5 and VO 2 are also present in the composite. The 0.6Li 3 V 2 (PO 4 ) 3 ·0.4Li–V–O electrode delivers a discharge capacity of 149.3 mAh g −1 at 50 mAg −1 between 2.0 V and 4.3 V, and has higher rate property than Li 3 V 2 (PO 4 ) 3 . The diffusion coefficients of Li ions in the composite are in the range of 10 −9.5 − 10 −7.5 cm 2 s −1 obtained from galvanostatic intermittent titration technique (GITT).

Ti-doped amorphous carbon multilayer films with different Ti content are deposited on medical Ti6Al4V alloy using a closed field unbalanced magnetron sputtering. The microstructure and chemical composition are characterized by high resolution transmission electron microscopy (HRTEM), atomic force microscopy (AFM) and X-ray photoelectron spectroscopy (XPS). The mechanical and tribological properties are evaluated by nanoindentation, Rockwell and scratch tests and ball-on-disk tribometer. The Ti content has a significant influence on the microstructure, mechanical and tribological properties of Ti doped a-C multilayer films. TiC nanocrystallites started to form in the a-C:Ti layer when the Ti target current density was above 2.58 mA cm − 2 during multilayer deposition process. Among these multilayers, the film deposited with a Ti target current density of 4.13 mA cm − 2 displays high hardness (25.2 GPa), high critical load (about 80 N), and low friction coefficient and wear rate in ambient air and in Hank's solution.

Abnormal growth of one-dimensional (1-D) ZnO nanostructures (NSs) have been accomplished with the assistance of polyvinylpyrrolidone (PVP) under a super high alkaline alcoholic solvothermal condition. The products were characterized by transmission electron microscopy (TEM), thermogravimetric analysis (TGA), X-ray diffraction (XRD), Fourier transform infrared (FT-IR) and proton nuclear magnetic resonance (1H NMR) spectroscopy. The effect of synthetic conditions, such as reaction temperature and the addition of PVP, on the morphologies of ZnO products were investigated. The results show that PVP molecules had the significant role in the transformation of morphologies of ZnO NSs ranging from nanorods, nanoparticles to pyramids, as well as flower-like assembly features. The possible growth mechanism of ZnO pyramids was proposed based on ring-opening reaction of PVP.

A Si/porous reduced graphene oxide (rGO) composite film synthesized by evaporation and leavening method are developed as a high-performance anode material for lithium ion batteries. The porous structure as buffer base can effectively release the volume expansion of the silicon particles, increase the electrical conductivity and reduce the transfer resistance of Li ions. The Si/porous rGO composite film presents high specific capacity and good cycling stability (1261 mA h g−1 at 50 mA g−1 up to 70 cycles), as well as enhanced rate capability. This approach to prepare such a unique structure is a low-cost and facile route for the silicon-based anode materials.

As promising battery-type electrode materials, layered single metal hydroxides (LSHs) including α-Ni(OH)2 and α-Co(OH)2 based hybrid supercapacitors exhibit larger operating voltages compared with those that are based on activated carbons and double-layer capacitance mechanisms. This study proposes a novel and facile room-temperature method to fabricate α-Ni(OH)2 and α-Co(OH)2 superstructures by using the double hydrolysis of Ni2+ or Co2+ and NCO− without the presence of any structure directing agent. Two dimensional sheet-like building blocks of the alpha-type metal hydroxide are assembled into various elegant morphologies including a 3D interconnected hierarchical assembly (3D-ICHA), sheet-on-sheet, sheet-on-rod and other nanostructures, which depends on the cation–anion mixing mode. Significantly, the 3D-ICHA α-Ni(OH)2 possesses an ultrahigh specific surface area (320.2 m2 g−1) and robust porous structure. An outstanding initial specific capacity (653.1 C g−1 at 1 A g−1 and 406 C g−1 at 20 A g−1) and an excellent cycling retention (86.2% in 20 000 cycles) were obtained for the 3D-ICHA α-Ni(OH)2, which stands out from most of the state-of-the-art α-Ni(OH)2 powder-based materials. A high-loading asymmetric capacitor with excessive activated carbon (∼10 mg 3D-ICHA α-Ni(OH)2vs. ∼60 mg activated carbon) is demonstrated and it works very steadily even after 20 000 charge/discharge cycles.

Three Ni–P–O compound catalysts with tunable architectures and compositions have been fabricated using a facile one-pot solvothermal method, which are named astrocyte-network Ni–P (Ni–Pan), silkworm cocoon-like Ni–P (Ni–Psc), and microsphere Ni–P (Ni–Pm), respectively. The final architecture of the Ni–P–O catalysts is strongly dependent on the Ni2+/H2PO2− molar ratio in the reaction system, which leads to a delicate balance between kinetic and thermodynamic growth regimes. Three-dimensional ensemble of Ni–Pan with a higher P content is composed of many amorphous Ni–P nanowires with a diameter of about 4 nm, which delivers a significantly larger BET surface area of 500.5 m2 g−1. Moreover, nickel phosphides and nickel phosphates are formed in the three Ni–P–O samples. Ni–Pan exhibits a higher peak current density of ∼1490 A g−1, better electrode accessibility, faster charge-transfer process, and long-term chronoamperometry stability (≥20 000 s) toward methanol oxidation in alkaline solution, which are superior to most state-of-art Ni–P catalysts and the Ni–Psc and Ni–Pm in this case. The superior catalytic performance of the Ni–Pan catalyst is attributed to its unique microstructure and compositions. According to X-ray photoelectron spectroscopy, a strong electronic interaction between nickel phosphides and nickel phosphates might also contribute to the improved catalytic activity of the Ni–Pan catalyst.