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Abstract Searching for advanced anode materials with exceptional electrochemical performance is essential for next-generation rechargeable batteries. The selection and structural design of anode materials are pivotal in the development of high-performance batteries. Herein, we demonstrate the preparation of uniform NiCo 2 O 4 nanotubes via a simple and cost-effective electrospinning technique followed by calcination in the air. Impressively, the advantages and importance of NiCo 2 O 4 nanotubes as an anode in lithium-ion batteries (LIBs) is demonstrated, which surpass their respective monometallic oxides in terms of electrochemical performance. Encouragingly, the as-obtained NiCo 2 O 4 nanotubes as an anode for sodium-ion batteries (SIBs) exhibit appealing electrochemical performance, such as high initial discharge capacity (879 mAh g−1 at 100 mA g−1), good rate capability, and excellent cycling stability. Moreover, a reversible capacity of 420 mAh g−1 at a current density of 100 mA g−1 can be maintained even after 100 cycles, corresponding to around 72% of the second cycle discharge capacity (584 mAh g−1). It is worth noting that this facile technique may provide a feasible way for the preparation of other functional materials with tube-like architectures for application in energy-storage device. Graphical abstract An advanced NiCo 2 O 4 nanotubes anode has been successfully prepared through a simple and cost-effective electrospinning technique followed by calcination in air. The as-obtained NiCo 2 O 4 nanotubes exhibits appealing electrochemical performance, such as high initial discharge capacity, good rate capability, and excellent cycling stability. Image 1 Highlights • NiCo 2 O 4 nanotubes are prepared through an electrospinning technique. • The NiCo 2 O 4 nanotubes surpass their respective monometallic oxides in terms of electrochemical performance in LIBs. • The NiCo 2 O 4 nanotubes as anode for SIBs present excellent electrochemical properties. • The electrospinning technique can be extended to prepare other functional materials in energy-storage devices. [ABSTRACT FROM AUTHOR]

Novel Pr 3+ , Ho 3+ , and Er 3+ single-doped Ca X Sr Y Ba 1−X−Y WO 4 phosphors were successfully prepared via a facile hydrothermal method. The hydrothermal process was conducted in aqueous condition without the use of any organic solvent, surfactant, or catalyst. The effects of doping-host composition and RE 3+ doping concentration on the emission intensity were investigated to optimize the luminescent properties of Ca X Sr Y Ba 1−X−Y WO 4 :RE 3+ phosphors. Experimental results demonstrate that the morphologies of the products vary gradually and regularly with the change of the host composition, in which the anisotropic growth played a key role. Moreover, the down-conversion emissions of Pr 3+ , Ho 3+ , and Er 3+ in Ca X Sr Y Ba 1−X−Y WO 4 host were successfully realized. After optimizing the luminescent properties, Ca 0.4 Sr 0.6 WO 4 :0.01Pr 3+ , Ca 0.8 Sr 0.2 WO 4 :0.01Ho 3+ , and Ca 0.6 Sr 0.4 WO 4 :0.005Er 3+ exhibited optimal luminescent property, with orange, yellowish-green, and green emissions, respectively. [ABSTRACT FROM AUTHOR]

Abstract: Eu3+ and Tb3+ co-doped NaLa(MoO4)2 phosphors with various shapes have been synthesized by a simple conventional hydrothermal method. The morphology of the materials was found to be manipulated by changing the pH value of the precursor hydrothermal media. Uniform NaLa(MoO4)2 3D microspheres could be trapped at pH 5 and the spindle-like NaLa(MoO4)2 microstructures were obtained at pH 7. When the pH value was adjusted to 9, the flower-like NaLa(MoO4)2 microstructures were obtained. The luminescent properties of the NaLa(MoO4)2:Eu3+/Tb3+ samples with different morphologies prepared at different starting pH values were studied. The results show that the emission intensity of the product obtained at pH 5 is the strongest. Besides, under ultraviolet excitation the luminescence colors of NaLa(MoO4)2 samples co-doped with Eu3+ and Tb3+ can be tuned from red, through yellow and green–yellow, to green by simply adjusting the relative doping concentrations of the activator ions. This merit of multicolor emissions in the visible region endows the as-prepared products with potential application in the fields of light-display systems and optoelectronic devices. [Copyright &y& Elsevier]

Core-shelled NiFe 2 O 4 /NiO@Fe 2 O 3 nanocubes were synthesized based on Prussian blue analogues. The core-shelled structure was built through ion-exchange process in aqueous solution, and was remained after calcination. Different concentrations of ferrous affect the size and surface states of PBA precursors and its successor. Fabricated core-shelled NiFe 2 O 4 /NiO@Fe 2 O 3 nanocubes produced with the PBA precursor that soaked in the solution of ferrous ion with the highest concentration in this work appears the most stable capacity during cycles, because of its more homogeneous Fe 2 O 3 layer surface and more complete crystal. At the current density of 100 mA/g, it offers an initial capacity of 1587.96 mA h/g, and the second capacity of 967.91 mA h/g, that was remained as 806.1 mA h/g after 50 cyles. At 500 mA/g, it performs a capacity of 472.5 mA h/g after 500 cycles with a strong stability. • Core-shelled structure is built through ion exchange process. • Ion concentrations in ion exchange process sever different surfaces. • Complete Fe 2 O 3 shell layer permits more stability during cycling. • Suitable calcined temperature is detected for high performance material. [ABSTRACT FROM AUTHOR]

A facile two-step method is developed to synthesize three dimensional (3D) hierarchical CaCo 2 O 4 architectures as high-performance electrode materials for lithium ion batteries (LIBs) and oxygen evolution reaction (OER). Our strategy involves a simple poly(vinylpyrolidone) (PVP)-assisted hydrothermal route and subsequent thermal treatment to produce flowerlike CaCo 2 O 4 nanostructures with a size of ∼500 nm, which is constructed by some neighboring vertical nanoplates. Whereas, the absence of PVP results in the formation of CaCo 2 O 4 microspheres, further indicating the vital role of PVP in favor of the oriented crystal growth of Co-based oxides. Benefited from the unique structural features, the resultant CaCo 2 O 4 nanoflower presents excellent cycling stability (∼560 mAh g−1 after 100 cycles at 50 mA g−1) and remarkable rate capability. Apart from superior lithium storage properties, more strikingly, CaCo 2 O 4 nanoflower demonstrates a promising candidate as a noble metal-free electrocatalyst for oxygen evolution reaction, which will spur us to find more novel functional nanomaterials for wide applications. • 3D hierarchical CaCo 2 O 4 architectures have been synthesized. • CaCo 2 O 4 nanoflower presents high lithium-storage performance. • CaCo 2 O 4 nanoflower presents high oxygen evolution reaction performance. [ABSTRACT FROM AUTHOR]

With K + as charge compensator, a series of KSr 4 (BO 3 ) 3 :Dy 3+ , Tb 3+ phosphors were successfully synthesized by solid–state reaction process. Under near-ultraviolet excitation (389 nm), the green emission of Tb 3+ is observed in Dy 3+ /Tb 3+ codoped samples due to the efficient energy transfer from Dy 3+ to Tb 3+ . The energy transfer efficiency, average donor-acceptor distance, as well as transfer mechanism were also studied. The energy transfer efficiency of KSr 4 (BO 3 ) 3 :Dy 3+ , xTb 3+ increased gradually and reached about 60% when the concentration of Tb 3+ was 0.030. And the critical distance R Dy-Tb was calculated to be 15.36 Å. Moreover, the energy transfer mechanism from Dy 3+ to Tb 3+ in KSr 4 (BO 3 ) 3 host was demonstrated to be dipole–dipole interaction. In addition, the emitting colors of Dy 3+ /Tb 3+ codoped samples can be adjusted from the edge of white area to green via tuning the Tb 3+ doped concentration. [ABSTRACT FROM AUTHOR]

Sphere-like and cauliflower-like hexagonal-vaterite LuBO 3 have been successfully synthesized for the first time via a chemical conversion route using Lu(OH)CO 3 colloid spheres as sacrificial precursor and H 3 BO 3 as boron source without any additional surfactant. FTIR analysis provides an additional evidence of the formation of vaterite-type LuBO 3 in this method. It was found that, an appropriate amount ethanol in the hydrothermal process has a great effect on the products' morphology and crystallinity. Time-dependent experiments indicate that the formation of LuBO 3 crystals went through a two-stage growth process, which involves a fast nucleation of primary particles followed by a slow aggregation and crystallization of primary particles. An investigation on the photoluminescence (PL) properties of LuBO 3 :Eu 3+ phosphors with different morphologies indicates that their PL intensity are dependent on their crystallinity. The effect of Eu 3+ and Tb 3+ doping concentration on PL intensity were also investigated and the quenching concentration of LuBO 3 :Eu 3+ and LuBO 3 :Tb 3+ is 0.25 and 0.20, respectively. Moreover, for Eu 3+ /Tb 3+ doped LuBO 3 phosphors, the color tones can be tuned from green, through green–yellow and yellow, and then to red by simply adjusting the relative doping concentrations of the Tb 3+ and Eu 3+ ions. [ABSTRACT FROM AUTHOR]

Lightweight equipment in aerospace and other fields urgently requires magnesium (Mg) alloys components with high-strength plasticity. For this reason, in this study, a gradient heterogeneous structure containing nanocrystallines was constructed successfully using a severe shear deformation process that combines severe plastic deformation techniques and torsional deformation characteristics. The evolution of the microstructure and hardness of Mg-12.12Gd-4.2Y-2.28Zn-0.36Zr (wt%) alloys prepared by severe shear deformation with changes in deformation temperature were investigated. The gradient heterogeneous structure of the alloys formed naturally under high hydrostatic pressure and severe shear stress, and its thickness increased with the deformation temperature. With the application of shear stress, a large amount of rotational dynamic recrystallization (RDRX) behavior occurs in the alloys, refining the coarse initial grains (∼126.3 µm) into fine grains (∼2.03 µm) or even ultrafine grains (∼1 µm). During the RDRX process, low angle grain boundaries (LAGBs) began to form at high distorted grain boundaries and unique lamellar structures, followed by a rapid expansion into the interior of the grains, which ultimately results in the grains being completely covered by subgrains. Meanwhile, the continuously broken long-period stacking-ordered (LPSO) phase and the precipitated bright rare earth rich (RE-rich) phase provide a large number of nucleation sites, further promoting the refinement process of the grains. Subsequently, the grains were further refined to nanocrystallines through the formation and rotation of subgrains under continuous loading of stress. The massive formation of nano-precipitated phases (β phases) along grain boundaries were accompanied by the complete disappearance of other types of second phases. The sources of β phases formation include the layer-by-layer decomposition of the cellular phases and the dissolution/re-precipitation of the LPSO phases. In addition, the introduction of shear stress promotes the random orientation of the DRXed grains through the extensive activation of pyramidal and pyramidal slip. The hardness of the alloys gradually decreased as the cumulative strain decreased at different deformation temperature conditions. When the deformation temperature was 440°C, the alloys reached a maximum hardness of 127.67 HV, which was nearly 43.5% higher than homogenized alloys. The ultra-high hardness of the alloys prepared by severe shear deformation is mainly attributed to grain boundary hardening, diffusion hardening and hetero-deformation induced (HDI) hardening. • Gradient heterostructures can be naturally constructed by severe shear deformation and the intense plastic deformation zone can reach 2.4 mm. • A large number of NM particles are obtained by the layer-by-layer decomposition of the cellular phase and dissolution/re-precipitation of the LPSO phase, which are pinned at nanograin boundaries to inhibit grain growth. • The introduction of shear stress promoted the random orientation of grains through the extensive activation of pyramidal and pyramidal slip. • The significant increase in hardness is mainly due to grain boundary hardening, diffusion hardening and HDI hardening. [ABSTRACT FROM AUTHOR]

A novel, fast and simple method was developed to synthesize the undoped and lanthanide-doped yttrium oxide hollow nanospheres (Y 2 O 3 ⋅HNSs) with multicolored downconversion emission under mild conditions by employing poly (acrylic acid sodium salt) microspheres (PAAS MSs) as active templates followed by a subsequent calcination process. The structure, morphology, formation process, and fluorescent properties are well investigated using various techniques. The results show that the samples can be well indexed to the pure cubic phase of Y 2 O 3 . The possible formation mechanism of the PAAS MSs, PAA-Y precursor, and Y 2 O 3 HNSs are proposed and discussed in detail. Upon ultraviolet excitation, the obtained Y 2 O 3 :Ln 3+ (Ln = Eu, Dy, Er, Tm) HNSs exhibit strong red, yellow–green, blue, yellow emission, respectively. Moreover, a novel single-phased and near-UV-pumped white-light-emitting phosphor Y 2 O 3 :Tm 3+ , Dy 3+ was also successfully fabricated through optimizing the molar ratio among Tm 3+ and Dy 3+ in the Y 2 O 3 host. This material may find potential applications in field-emission display devices and white ultraviolet light-emitting diodes (UV LEDs). Furthermore, this synthesis route may be of great significance in the preparation of other hollow spherical materials. [ABSTRACT FROM AUTHOR]

Abstract: The NaLa(MoO4)2:Ce3+,Tb3+ phosphors were synthesized by a high temperature solid-state reaction. Co-doping of Ce3+ enhances the emission intensity of Tb3+ greatly by transferring its excitation energy to Tb3+. Through an efficient energy transfer process, the obtained phosphors exhibit both a indigo emission of Ce3+ and a yellowish green emission of Tb3+ with considerable intensity under near-ultraviolet excitation (339nm). The energy transfer mechanism from Ce3+ to Tb3+ in NaLa(MoO4)2 host was demonstrated to be dipole–quadrupole interaction. The varied emitted color of the phosphors from indigo to yellow-greenish can be achieved by properly tuning the relative ratio of Ce3+ and Tb3+ through the energy transfer from the Ce3+ to Tb3+ ions. These results indicate that the NaLa(MoO4)2:Ce3+,Tb3+ phosphors have potential applications as an UV-convertible phosphor for white light emitting diodes because of its effective excitation in the near ultraviolet range. [Copyright &y& Elsevier]

N-doped carbon supported MOFs derived P-doped ZnCo 2 O 4 nanosheets (ZCP/NC) with rich oxygen vacancy are rationally designed and synthesized via a chemical heat treatment strategy. In the unique structure, N-doped carbon as a skeleton can provide an electrically conductive 3D continuous network with large surface area for the growth of active materials. P-doped ZnCo 2 O 4 nanosheets are rich in oxygen vacancies and have a large exposure area, which can enhance the charge storage capabilities. Electrochemical measurement displayed that the novel electrodes can deliver a highest specific capacitance of 1581.5 F g−1 at 1 A g−1. An asymmetric supercapacitor (ASC) fabricated by ZCP/NC and activated carbon can reach a high energy density of 47.8 Wh kg−1 at power density of 800 W kg−1. Besides, The ASC also exhibits a cyclic retention of 90.6% for 5000 cycles. The reasons for excellent properties of ZCP/NC are discussed in detail. ga1 3D N-doped carbon supported MOFs derived P-doped ZnCo 2 O 4 nanosheets with rich oxygen vacancies showed a superior electrochemical performance. • 3D N-doped carbon supported MOFs derived P-doped ZnCo 2 O 4 nanosheets are successfully prepared. • P-doped ZnCo 2 O 4 nanosheets are rich in oxygen vacancies can enhance the charge storage capabilities. • The unique electrode displays a high capacitance of 1581.5 F g−1. • The hybrid supercapacitor achieves a high energy density of 47.8 Wh L−1. [ABSTRACT FROM AUTHOR]

Titanium foam (TiF) as a kind of implantable biomaterials has good mechanical properties and three-dimension (3D) micro-porous structure, which has potential applications in bone tissue engineering. However, their clinical application is technically restricted by their bio-inert property with limited cross-interaction with biological microenvironment and cells. In this work, a facile approach was proposed to construct surface nanostructure and metal ion incorporation for titanium foam to regulate the attachment and osteogenic differentiation of bone marrow derived mesenchymal stem cells (MSCs). This modification was realized by a hydrothermal treatment following a Mg 2+ or Ca 2+ ion-substitution process. The assessment of cell morphology, viability, gene and protein expression of MSCs grown on the surface nanostructured titanium form and different ion corporation showed that the surface nanostructure and Mg 2+ and Ca 2+ incorporation with proper concentration promoted the osteogenic differentiation of MSCs. Once beyond the proper concentration range, the promoting effect of osteogenesis was reduced. It provides a promising method for constructing 3D biomaterial in bone tissue engineering. [ABSTRACT FROM AUTHOR]

• Silicon is obtained from photovoltaic industrial waste through simple purification. • N-doped carbon ensures fast charge transfer and structural stabilization. • Si/NC electrode has a high specific capacity both in half-cell and full-cell. Silicon (Si) is considered to be one of the most promising anode materials for the next generation of lithium-ion batteries (LIBs). However, the practical application of Si anode is still high cost and hindered by huge volume change. It is significant to produce high-performance Si anode of LIBs inexpensively. Herein, we report the Si/N-doped carbon (Si/NC) composite anode materials constructed by recycling Si waste from the photovoltaic industry as raw materials after simple purification and polydopamine (PDA)-derived carbon coating. The Si micro/nano-plates coated with the NC can facilitate electron transfer and inhibit the volume expansion of Si to stabilize the structure of composites. The resulting Si/NC electrode exhibits a high discharge capacity of 1139 mAh g−1 at 1 A g−1 over 200 cycles. Moreover, the full-cell (LiFePO 4 //Si/NC) presents excellent cycling performance (108 mAh g−1 at 0.5 A g−1 over 200 cycles). This work not only offers a reasonable solution for the acquirement of Si anode from the photovoltaic industry but also provides a new strategy for the preparation of anodes for the next generation of LIBs, which may bring great economic benefits. [ABSTRACT FROM AUTHOR]

Two-dimensional (2D) layered materials were widely investigated due to their unique sodium storage properties and rapid ion transport rates. Herein, we synthesized a 2D layered transition metal phosphorus sulfide MnPS 3 by one step high-temperature solid-phase synthesis. After combining with graphene by high-energy ball milling followed by high-temperature argon calcination, the novel 2D/2D heterojunction of extra-thin MnPS 3 /rGO was successfully prepared. The resultant MnPS 3 /rGO hybrid can strengthen the conductivity of the material and ameliorate the volume change during the insertion/extraction process of the sodium-ion storage, compared to the pristine MnPS 3. As a result, the 2D/2D heterojunction of ultra-thin MnPS 3 /rGO composite exhibits high cycling performance (290 mAh g−1 after 150 cycles at 0.2 A g−1), capacity retention rates up to 92%. The superior performance is ascribed to the combination of extra-thin MnPS 3 nanosheets with graphene, which effectively enhances the interface contact area and the electronic transmission rate, greatly improving the adaptability of volume change and interfacial charge transfer abilities. This work provides a novel and promising MnPS 3 /rGO anode for sodium-ion batteries. Image 1 • Two-dimensional (2D) layered structure possesses rapid ion transport rates. • A novel 2D/2D heterojunction of MnPS 3 /rGO composites was synthesized by high-energy ball milling. • The introduction of various carbon species into 2D materials can effectively ameliorate the structure stability of materials. [ABSTRACT FROM AUTHOR]