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In this paper, we explore the asymmetry observed between the effects of photon–phonon coupling (nested-dressing) and a crystal field (CF) on the fine structure of fluorescence (FL) and spontaneous four-wave mixing (SFWM) in Eu3+: BiPO4 and Eu3+: NaYF4. The competition between the CF and the strong photon–phonon dressing leads to dynamic splitting in two directions. The CF leads to static splitting in one direction under weak phonon dressing. The evolution from strong dressing to weak dressing results in spectral asymmetry. This spectral asymmetry includes out-of-phase FL and in-phase SFWM. Further, the large ratio between the dressing Rabi frequency and the de-phase rate leads to strong FL and SFWM asymmetry due to photon–phonon constructive dressing. Moreover, the experimental results suggest the analogy of a spectra asymmetry router with a channel equalization ratio of 96.6%. [ABSTRACT FROM AUTHOR]

Long afterglow phosphor Y2O2S:Gd,Eu,Ti,Mg was synthesized by a gas absorption method and the effect of Ti4+ and Mg2+ ions doping on the luminescent properties was also investigated. Single phase Y2O2S can be obtained by calcining the oxide mixture in a graphite crucible absorbed with sulfur. Ti4+ and Mg2+ ions decrease the luminescent intensity of the phosphor, but either Ti4+ or Mg2+ ion doping results in red long afterglow. A strong thermoluminescence peak appears when codoping Ti4+ and Mg2+ ions in the phosphor. [Copyright &y& Elsevier]

A new phosphor Ca12Al14O33:Nd,Eu was synthesized by a traditional solid-state reaction method and the luminescent properties were investigated. The phosphors are well crystallized by calcination at 1200 °C. The excitation and the emission spectra show the characteristic broadband of the Eu2+ ion and the emission light is indigo. Doping Nd3+ ion in the phosphor results in indigo long afterglow phosphorescence (the time for the phosphorescence intensity to decrease to 10% of its initial value is about 50 s) when the excitation light is cut off. The emission intensity decreases with the increase of Nd3+ ion concentration. Whereas, the phosphorescence intensity and afterglow time improve when the concentration of Nd3+ ion increases. [Copyright &y& Elsevier]

In this work, the conditions for the preparation of stable nanometer zirconia slurries with high solids content for the production of aqueous-gel-tape-casting objects with improved properties are identified. Influences of the powder and dispersant on the rheological properties were investigated. The result indicated the polyelectrolyte dispersant greatly affected the surface charge of nanometer tetragonal zirconia powder and the rheological behavior of nanoparticles zirconia’s suspensions. For each factor there exists an optimum range in which low viscosity was achieved for a slurry of high solid content. The proper content of the dispersant is between 0.8 and 1.2 wt.%. The rheology character of high solid loading slurries is non-Newtonian flow—‘shear-thinning’ character as the shear rate is increased. The viscosity of the 77 wt.% powder loading slurry with about 1.0 wt.% polyelectrolyte (based on the powder) was 0.35 Pa s at the shear rate of 110 s−1. The slurry at the optimum conditions met the demands of aqueous-gel-tape-casting process. [Copyright &y& Elsevier]

The aim of the present work was to identify the conditions for the preparation of stable zirconia slurries with high solids content for the production of aqueous gel tape casting objects with improved properties. Influences of the powder and dispersant on the rheological properties were investigated. High stable low-viscosity nanoparticles zirconia suspensions were achieved. Nanometer-sized tetragonal polycrystal zirconia powder was synthesized by a new low-temperature environment-benign method. The oxide powders were confirmed to be 3Y-TZP single phase with tetragonal structure measured by X-ray diffraction analysis. Acryl amide (AM) and N,N′-methylene bisacrylamide (MBAM) have been used as organic monomer and cross-linker of the process, respectively. NH4PAA (M=5000–8000) has been used as polyelectrolyte dispersant. The electrokinetic behavior of nanometer-sized zirconia suspensions stabilized by various dispersant contents was studied. The result indicated the dispersant concentration greatly affected the surface charge of nanometer tetragonal zirconia powder. The isoelectric point (IEP) obviously changed from 8.1 to about 4.7 because of the addition of polyelectrolyte dispersant. To acquire stable low-viscosity slurries, the influences of several parameters on rheological behavior of nanosized tetragonal zirconia suspensions were investigated. It was found that for each factor, there exists an optimum range in which low viscosity was achieved for a slurry with high solid loading. For the slurry of 77 wt.% powder concentration with about 1.0 wt.% polyelectrolyte (based on the powder), the viscosity was 350 mPa s at the shear rate of 110 s−1. The slurry at the optimum conditions met the demands of aqueous gel tape casting process. [Copyright &y& Elsevier]

Eu3+-activated Y2O2S phosphors co-doped with Ti and Mg ions were prepared. The effect of various sintering atmospheric conditions on the crystalline phases and luminescent properties of the products were investigated in detail. Red and orange long afterglow was observed after phosphors were excited with 365 nm ultraviolet light. The main emission peaks were ascribed to Eu3+ ions transition from 5DJ (J=0,1) to 7FJ (J=0,1,2,3,4), and the phosphorescence lasted for nearly 3 h in the light perception of the dark-adapted human eye (0.32 mcd m−2). The phosphorescence mechanism was also investigated. [Copyright &y& Elsevier]

BaMgAl10O17:Eu powder was synthesized using a sol–gel process by dissolving BaCO3, Mg(OH)2·4MgCO3·6H2O, Eu2O3 and active Al(OH)3 in citric acid. By tracing the formation process of the sol–gel, it is found that decreasing the amount of NO3− in the solution is necessary for the formation of transparent sol and gel. Results from X-ray diffractionmeter (XRD), thermogravimetry (TG)–differential thermal analysis (DTA) and IR spectra show that BaMgAl10O17 crystallizes completely when the dry gel is sintered at 1300 °C. The phosphor particle takes the form of plates if the dry gel is sintered directly, while the particle is more regular when the dry gel is calcined and ground before sintering, and the crystallite size is in the range between 1 and 5 μm. The emission intensity of the phosphor is slightly higher than that prepared by solid-state reaction. [Copyright &y& Elsevier]

Metal nitrate aqueous solution was mixed with citric acid to synthesize the red-emission Y2O3:Eu phosphor by sol–gel processing. The samples remained amorphous below 600 °C and crystallized completely at 700 °C. Calcining and grinding were necessary to obtain phosphor with a particle size in the range between 0.5 and 2 μm of regular shape. The emission intensity increased with increasing sintering temperature and the intensity of the phosphor sintered after calcining and grounding decreased in comparison with that obtained by sintering the dry gel directly. [Copyright &y& Elsevier]

Nitrogen dioxide (NO2) is the major reason for acid rain and respiratory illness in humans. Therefore, rapid, portable, and effective detection of NO2 is essential. Herein, a novel and simple method to construct a ZnO-SnO2 heterojunction is fabricated by pyrolysis of bimetallic metal organic frameworks. The sensitivity of ZnO-SnO2 heterojunction towards 0.2 ppm NO2 under 180 °C is 37, which is 3 times that of pure ZnO and SnO2. The construction of heterojunction speeds up the response-recovery process, and this kind of material exhibits lower detection limit. The construction of heterojunction can significantly improve the NO2 sensitivity. The selectivity, stability, and moisture resistance of ZnO-SnO2 heterojunction are carried out. This could enable the realization of highly selective and sensitive portable detection of NO2. [ABSTRACT FROM AUTHOR]

Oxide solid electrolytes are attractive for the implementation of solid‐state Li‐ion batteries. However, constrained by the large ion‐transport hindrance inside the densely packed lattice, their Li‐ion conductivity can hardly reach the level of liquid electrolytes. A strategy of introducing confined water into the lattice paves a new way for enhancing the Li‐ion transport, which has been reported in the previous studies. To further verify the universality of this strategy and unravel the facilitation mechanism, here this work establishes an ideal model using Li‐H‐Cl‐O quaternary compounds with a wide electrochemical stability window. As a major kind of confined water, the content and type of ─OH groups are crucial parameters affecting the Li‐ion conductivity. Through a controllable dehydration technique, the hydrogen‐bonded ─OH groups can be mostly removed, leaving the free ─OH groups in lattice, which is beneficial to the increase of free volume and acceleration of rotation response. The 1–2 orders of magnitude enhancement of Li‐ion conductivity ensures full cells good rate and cycling performance. This work not only addresses the controversy in Li‐H‐Cl‐O about the hydrogen effect on Li‐ion transport, but also provides detailed theoretical insights for the rational design of solid electrolytes. [ABSTRACT FROM AUTHOR]

Tin disulfide nanostructured material has become a new gas sensing material thanks to its unique sensing properties. However, the mechanism of gas sensing of SnS 2 via the adsorption and desorption of gas molecules is not well understood yet. Herein we investigate the sensing behavior of nanosheets-assembled SnS 2 nanoflowers prepared by a simple hydrothermal method. The results showed that SnS 2 nanoflowers exhibited an excellent response to ppb of NO 2 (R g /R a =5.7 to 100 ppb and 25.4 to 500 ppb) at 120 °C, which makes them a promising candidate for high-performance low temperature sensing. It was also found that the sample had even higher response to NO 2 at N 2 atmosphere, which is different from the conventional chemisorption oxygen model where the presence of oxygen is essential. [ABSTRACT FROM AUTHOR]

To obtain high-performance spinel LiMn 2 O 4 , various types of hydrated layered-spinel lithium manganate composites have been controllably synthesized through the hydrothermal process. It is found that the composition and morphology of these intermediate products can be tuned by the concentration of LiOH: Li + act as the template and OH - provide the required alkaline environment. In particular, the nanostructure varies from nanowires to nanosheets at different levels, depending on the phase ratio of the spinel phase ranging from 0% to 100%. Phase purity and the corresponding electrochemical properties of the as-prepared LiMn 2 O 4 products are further tailored through the subsequent heat treatment. With the optimized LiOH concentration of 0.08 M, the resulting LiMn 2 O 4 cathode material exhibits the best electrochemical performance with the initial discharge capacity of 121.7 mA h g −1 at 1 C and 117.8 mA h g −1 at 30 C, while a retention over 90% can be achieved after 1500 cycles. This study will help deepen understanding of the function mechanisms and further direct the novel synthesis from hydrated layered-spinel lithium manganate composites to high-performance spinel LiMn 2 O 4 cathode materials. [ABSTRACT FROM AUTHOR]

Regulating the interlayer spacing of vanadium oxides by various pillars has commonly been used for improving zinc‐ion storage performance. However, most of the reported pillars are large and rigid, which sacrifices interlayer free volume, increases the steric hindrance, and results in large volume change. Herein, a layered vanadium oxide with –OH pillars by controllable heat treatment of layered vanadium oxide with rigid NH4+ pillars is prepared. Although the –OH pillars are small‐sized, they can firmly support the interlayers through the covalent bond. In addition, the rotatable –OH pillars can promote Zn‐ion diffusion and accommodate lattice deformation. Compared to the layered vanadium oxide with rigid pillars, the one with rotatable pillars shows a higher rate capability (321 mAh g−1 at 0.5 A g−1 and 83 mAh g−1 at 20 A g−1) and a better cyclability (93% capacity retention over 2000 cycles at 5 A g−1). Further mechanism studies demonstrate that the rotatable pillars show low‐hindrance and high‐stability to regulate the interlayer structure. It is emphasized that the interlayer microenvironment can not be neglected, but is crucial for advanced electrodes of aqueous zinc‐ion batteries, rather than pursuing larger interlayer spacing. [ABSTRACT FROM AUTHOR]

Dopamine (polydopamine) is an excellent and facile agent for achieving effective full carbon coating owing to its strong adhesive capability. Herein, polydopamine-derived carbon coating on LiMnPO 4 has been reported for the first time. Detailed investigations indicate that full carbon coating with the suitable thickness can significantly enhance the electrochemical performance of LiMnPO 4 /C composite by balancing the electronic conduction and lithium-ion transportation. Benefiting from the thin full carbon coating with a relatively uniform thickness of 3-5 nm, the as-obtained LiMnPO 4 /C composite with 6.84 wt.% carbon exhibits a high reversible capacity of 118 mAh g −1 at 5 C and 106 mAh g −1 at 10 C, respectively, and a remarkable stable capacity retention of ∼91.5% after 100 cycles at 0.5 C. Moreover, attractive electrochemical properties can also be obtained for LiMnPO 4 /C composite with reduced carbon content of 3.41 wt.%. The above results are competitive among the low carbon coated LiMnPO 4 based materials. [ABSTRACT FROM AUTHOR]

Abstract: Mesoporous lithium aluminate (α-LiAlO2) hollow spheres with the diameter of 3–4μm and the shell thickness of about 500nm have been successfully synthesized by a hydrothermal method with template-assisted. Many mesopores were found on the surface of the spherical shell. Nitrogen sorption measurement reveals that obtained products exhibited high BET specific surface area up to 322.8m2/g and pore volume of 0.72cm3/g. The formation mechanism of the mesoporous shell structure was proposed as a core-shell-surfactant-water model. [Copyright &y& Elsevier]

Abstract: Lithium aluminate (α-LiAlO2) nanobelts with the length of 1–2 μm and the thickness of about 25 nm have been successfully synthesized by a hydrothermal method with template assisted. The structure and morphology of the as-prepared products are characterized by X-ray diffraction, scanning electron microscopy, and transmission electron microscopy. Each nanobelt is single crystal structure, and many mesopores are discovered on the surface of the nanobelts. Nitrogen sorption measurements reveal that obtained products exhibited high BET specific surface area up to 224 m2/g and pore volume of 0.72 cm3/g. The growth mechanism of the nanobelts is proposed and the influence of pH value on the morphology is discussed. [Copyright &y& Elsevier]

Abstract: Mesoporous materials, due to its potential for advanced applications in catalysis and nanoscience, have attracted much attention in the past decade. In this work, mesoporous lithium aluminate (next called MLA) nanosheets with high specific surface area were prepared by a hydrothermal method using hex-adecyltrimethyl ammonium bromide (CTAB) as the template. A novel PEO-based composite polymer electrolyte has been developed by using MLA powders as the filler. The electrochemical impedance showed that the conductivity was improved simultaneously. A high conductivity of 2.24×10−5 Scm−1 at 25°C was obtained. The lithium polymer battery using this novel composite polymer electrolyte and with lithium metal and LiFePO4 employed as anode and cathode, respectively, showed high discharge capacity (more than 140mAhg−1 at 60°C) and excellent cycling stability as revealed by galvanostastically charge/discharge cycling tests. The excellent electrochemical performances at low temperature of the cells were obtained, which was attributed to the high surface area and channels structure of the filler. The excellent properties of the solid-state lithium battery suggested that, PEO16–LiClO4–MLA composite polymer electrolyte can be used as a candidate material for lithium polymer batteries. [Copyright &y& Elsevier]

Abstract: Mesoporous α-LiAlO2 powders have been successfully prepared by a hydrothermal route based on using the surfactant CTAB as the template. The structure and morphology of the products were characterized by X-ray diffraction (XRD) and transmission electron microscopy (TEM). The crystallization transition process of the precursor after hydrothermal reaction was investigated by thermal gravity analysis. The prepared lithium aluminate had a morphology of two-dimensionally mesoporous nanoflakes with single crystal structure. A high specific surface area up to 124 m2/g was obtained by this method. [Copyright &y& Elsevier]

Abstract: The electrochemical kinetics of lithium intercalation in hydrogen titanate nanotubes was investigated by detailed cyclic voltammetric methods. The results show pseudocapacitive faradaic characteristic of lithium storage in these nanotubes. The microstructure and morphology of electrode lamina before and after galvanostatic cycles were characterized by scanning electron microscopy. No obvious microsturcture changes were observed after 50 cycles, which was in well accordance with the excellent galvanostatic cycling stability. The pseudocapacitive behaviors of lithium storage in these nanotubes are ascribed to the open-end and layered scrolling cross-section with much larger inter-layer spacing than normal lithium intercalation materials. [Copyright &y& Elsevier]

Abstract: Phase pure, well-crystallized and homogeneous LiFePO4 powder with inverse opal structure was obtained by calcining the precursors of Li+, Fe2+ and PO4 3− in the presence of organic template of poly(styrene-methyl methacrylate-acrylic acid) latex micro-spheres under nitrogen atmosphere. The resultant products were characterized by X-ray powder diffraction (XRD), scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), chemical titration, Fourier transform infrared (FTIR) and Land 2001A electrochemical measurement system. Results indicated that after the decomposition of organic template, inverse opal structure and conductive carbon were left in the resultant products. With the large specific surface area resulting from inverse opal structure and with the conductive carbon, the products delivered satisfactory capacity and superior rate capability at room temperature, i.e., over 100mAh/g at the high current density of 5.9C. [Copyright &y& Elsevier]

Abstract: Novel spinel Li4Ti5O12 with nanotubes/nanowires morphology and high surface area has been prepared by a low temperature hydrothermal lithium ion exchange processing from hydrogen titanate nanotubes/nanowires precursors. The shape and morphology of spinel Li4Ti5O12 are controllable by varying the hydrogen titanate precursors (nanotube, nanowire, nanorod and nanobelt) from alkaline-hydrothermal approach. The crystal structure and morphology of the as-prepared lithium titanate nanotubes/nanowires have been investigated by TEM, HRTEM and XRD, respectively. The formation temperature of spinel Li4Ti5O12 nanotubes/nanowires is lower than that of bulk materials counterpart prepared by solid-state reaction or by sol–gel processing. The well reversible cyclic voltammetric results of both electrodes indicate enhanced electrochemical kinetics for lithium insertion. These novel one-dimensional nanostructured materials may find promising applications in lithium ion batteries and electrochemical cells. [Copyright &y& Elsevier]

Abstract: Nanostructured electrodes have been shown to exhibit enhanced rate capability and large discharge/charge capacity for lithium intercalation and extraction. In this paper, electrode made of H-titanate nanotubes show large lithium intercalation capacity, high discharge/charge rate capabilities and excellent cycling stabilities. A facile way is adopted to fabricate well-dispersed nanostructured electrode film by in situ ultrasonic dispersion in N-methyl pyrrolidone. The electrode film containing H-titanate nanotubes, conductive black and polyvinylidene fluoride binder is coated on aluminum foil. The material exhibits an initial discharge capacity of 282.2 mAh/g at a current density of 0.24 A/g, and keeps a stable cycling discharge capacity of 210, 185.7 and 165.9 mAh/g at current density of 0.24, 1.0 and 2.0 A/g, respectively, demonstrating large reversible capacity and excellent rate capabilities. An about 100% of coulombic efficiency implies the perfect reversibility of lithium intercalation into and release from the H-titanate nanotubes and thus the extraordinary cycling stability. The results indicate that this layered, open ended nanotubes may become a candidate for novel lithium storage material with high capacity, high rate capability and excellent cycling stability. [Copyright &y& Elsevier]

The n-type semiconducting BaTiO3-based positive temperature coefficient of resistivity (PTCR) ceramics is a potential CO gas sensing material with its high temperature NTCR region. The impedance spectroscopy was employed to analyze the resistance evolution of grain and grain boundary in atmospheres for the PTCR ceramics with various Curie point. The XPS studies were carried out at the temperatures from room temperature to 340 °C to understand the sensing characterization of BaTiO3-based PTCR ceramics. It is indicated that the sensing mechanism for the PTC–CO gas sensor is due to oxygen desorption at the grain boundary or an increase in charge carrier density and related chemical defects, which are based on the fluctuation of the potential barrier of the grain boundary. [Copyright &y& Elsevier]

Pure and Sr/Mg doped LaGaO3 were synthesized by standard ceramic process. Their electrical conductivity and crystal symmetry were investigated by dc four-probe and Raman spectroscopy, respectively. Raman analysis revealed rhombohedral structure in La0.9Sr0.1Ga0.9Mg0.1O2.9 (LSGM1010) and LaGa0.8Mg0.2O2.9 (LGM20), while detected orthorhombic symmetry in La0.8Sr0.2GaO2.9 (LSG20) and pure LaGaO3. Electrical measurement found that LSGM1010 and LGM20 have similar ionic conductivity, which is higher than that of LSG20. The experimental results strongly indicate that high ionic conductivity prefer high symmetry in doped LaGaO3. An attempted explanation was offered to illustrate the interesting phenomena based on XPS study. [Copyright &y& Elsevier]

The aim of the present work was to identify the conditions for the preparation of stable zirconia slurries with high solid loading for the production of aqueous-gel-tape-casting objects with improved properties. Influences of the powder and dispersant on the rheological properties were investigated. The result indicated that the polyelectrolyte dispersant greatly affected the surface charge of nanometer tetragonal zirconia particle and the rheological behavior of nanometer sized polycrystal zirconia suspensions. For each factor there exists an optimum range in which low viscosity was achieved for slurry of high solid loading. The proper dispersant content is between 0.8 and 1.2 wt.%. The rheological behavior of high solid loading slurries is non-Newtonian flow-‘shear-thinning’ character as the shear rate is increased. The viscosity of the 77 wt.% powder loading slurry with ≈1.0 wt.% polyelectrolyte (based on the powder) was 750 mPa s at the shear rate of 48 s−1. The slurry at the optimum conditions met the demands of the aqueous-gel-tape-casting process. [Copyright &y& Elsevier]

2∼3.5 mol%Y2O3 stabilized zirconia powders were prepared by mixing pure zirconia and Y(NO3)3 solution. The sintering ability of these powders was investigated. The results show that with the increasing amount of yttria, the grain size decreases while the density and the (t+c)-ZrO2 phase fraction increase. It is not sufficient in stabilizing all the zirconia when the doped yttria is less than 2.5 mol%. Several experimental rules about the microstructure and phase content developing with sintering temperature and soaking time are presented. The critical grain size for the retention of high-temperature tetragonal phase in 3Y-TZP is about 0.5 μm. A 3Y-TZP sample with grain size about 0.3 μm, relative density higher than 99%, (t+c)-ZrO2 phase fraction more than 90%, was obtained when it was sintered at 1450 °C for 2 h in air. [Copyright &y& Elsevier]

Long afterglow R3MgSi2O8:Eu2+, Dy3+ (R=Ca, Sr, Ba) phosphors were prepared at high temperature and weak reductive atmosphere. The excitation and emission spectra of these phosphors showed that all are broadband due to 4f7–4f65d transitions of Eu2+, and the main emission peaks at 471.3, 458.2 and 439.1 nm, respectively. The decay curves indicated that all of these phosphors have long afterglow features, and the Sr3MgSi2O8-based phosphor has better afterglow properties than the other phosphors. [Copyright &y& Elsevier]

CaAl2O4: Eu, RE3+ (RE: Dy, Nd, La) photoluminescent materials with high brightness and long afterglow are prepared by sintering at high temperature and in a reductive atmosphere. The influence of co-doping rare earth ions (Dy, La and Nd) on the luminescence of CaAl2O4: Eu was studied. The excitation and emission spectra of these three kinds of phosphors are very similar to that of CaAl2O4: Eu phosphor, and all of them have long afterglow phenomenon except for CaAl2O4: Eu. Both of initial brightness and persistent afterglow time of CaAl2O4: Eu, Nd is better than those of CaAl2O4: Eu, Dy, and CaAl2O4: Eu, La, which is agreement with the results of thermoluminescence curves. The low temperature photoluminescent spectra indicate that Eu ions occupied only one kind of Ca site in CaAl2O4 crystal lattice. [ABSTRACT FROM AUTHOR]

Oil flotation is a separation process that has widely been utilized in the separation and purification of minerals from raw ores. In the current study, this process was combined with coprecipitation process to prepare nanosized 8 mol% yttria-stabilized zirconia (8YSZ) powder. One of the most attractive characteristics of the oil flotation-assisted process is that highly hydrophilic hydroxide precipitate can be transformed to hydrophobic and directly be extracted from aqueous phase to oil phase with the help of SPAN80 (flotation reagent). After laundering with water, the precipitate was dried to recover oil and fired to oxide at 800 °C. [Copyright &y& Elsevier]

Metal nitrate aqueous solution was mixed with citric acid to synthesize the red emission nanometer Y2O3:Eu phosphor by simple sol–gel processing. Structure characterization of the phosphor was carried out by XRD and TEM. The samples are mostly amorphous when the dry gel is calcined below 500 °C and crystallize completely at 600 °C, and the crystallity increases with increasing calcining temperature. The mean particle size increases from about 10 to 50 nm when the calcining temperature increases from 600 to 900 °C, while that calcined at 1250 °C is about 100 nm. The luminescence property of the phosphor was analyzed by measuring the excitation and emission spectra. The luminescence intensity increases when the calcining temperature increases and luminescence intensity is higher than that prepared by solid-state reaction method when the concentration of Eu3+ and the calcining temperature are the same. [Copyright &y& Elsevier]

Li1.03Mn1.97O4 spinel material was coated with a thin layer of SiO2 by a sol–gel method. The surface modification was found to reduce the Mn2+ dissolution into the electrolyte according to the inductively coupled plasma (ICP) analysis results and improve the capacity retention of the Li1.03Mn1.97O4 spinel. The structure and properties of the coating materials were also investigated by X-ray photoelectron spectra (XPS) analysis, X-ray diffraction (XRD) patterns and Transmission electron microscope (TEM). [Copyright &y& Elsevier]

[Display omitted] • −OH content in anti-perovskites is regulated through simple heat treatment. • The ionic conductivity of Li 2 (OH)Cl at 30 °C is significantly enhanced. • The cubic phase appears and the phase transition temperature decreases. • Calculations demonstrate significant decrease in diffusion barrier. • This work advances the practical application of anti-perovskites in ASSLBs. Anti-perovskite materials such as Li 2 (OH)Cl have garnered considerable interest as solid electrolytes due to their numerous advantages. However, the low ionic conductivity of the orthorhombic Li 2 (OH)Cl near room temperature presents a significant challenge for the application. In this study, we intricately modulate the −OH content in Li 2 (OH)Cl through a controlled heat treatment process. This method effectively increases the cubic phase content and lowers the phase transition temperature, thereby enhancing the ionic conductivity at 30 °C by more than an order of magnitude. Theoretical calculations illustrate that the removal of −OH content significantly reduces the barrier for phase transition, leading to substantial alterations in the Li-ion transport pathway and migration barrier. Furthermore, LiHClO-600 demonstrates exceptional resistance to lithium reduction and is compatible with lithium metal and LiFePO 4 , rendering it a viable solid electrolyte for batteries. Both experimental findings and theoretical calculations cohesively highlight the pivotal role of −OH content in driving phase transition and facilitating Li-ion transport in anti-perovskite solid electrolytes, paving the way for their potential utilization in all-solid-state batteries. [ABSTRACT FROM AUTHOR]

• The SnO 2 @SnS 2 sensor based on the hollow structure and visible light assistant for highly sensitive detection of ppb-level NO 2 at room temperature (25 °C). • The underlying sensing mechanism of the SnO 2 @SnS 2 based NO 2 sensor under the visible light irradiation was discussed. • The different effects of humidity on the responses of the SnO 2 @SnS 2 sensor to different concentrations of NO 2 were studied and explained. SnS 2 is a promising candidate for NO 2 sensing applications due to its suitable band gap and large electronegativity. However, SnS 2 based gas sensors are still restricted to detect NO 2 gas at room temperature due to their giant resistance and poor recovery. Here, we report hollow SnO 2 @SnS 2 nanostructures prepared by a one-step hydrothermal method. The SnO 2 @SnS 2 based sensor showed high response and good recovery to ppb-level NO 2 under visible illumination at room temperature (25 °C). The superior sensing performance of the SnO 2 @SnS 2 sensor was attributed to the hollow porous heterojunction structure beneficial for gas diffusion, as well as visible light assistant facilitating charge transfer and gas desorption. This work systematically studied the influence of oxygen concentration in background gas on the NO 2 sensing performance of the SnO 2 @SnS 2 sensor, and proposed a physical adsorption model for the NO 2 sensing mechanism of the SnO 2 @SnS 2 sensor under visible light at room temperature. In addition, the effect of humidity on the gas sensing performance of the SnO 2 @SnS 2 sensor to different concentrations of NO 2 was also discussed. [ABSTRACT FROM AUTHOR]

• WS 2 nanosheets with edge size about 10 nm were synthesized by the sulfurization of the WO 3 nanomesh. • The sensor based on WS 2 nanosheets exhibited p-type sensing properties and excellent selectivity to NO 2 gas at a low temperature of 160 °C. • The different sensing mechanisms of WS 2 nanosheets for NO 2 and H 2 S sensing were proposed based on the experimental results. Due to their high intrinsic conductivity and narrow band gap, nanostructured metal sulfides have attracted considerable attention as promising gas sensing materials. Here, we report the WS 2 nanosheets with edge size only about 10 nm synthesized by sulfurization of the WO 3 nanomesh. The WS 2 nanosheets exhibit p-type sensing characteristics and excellent selectivity to NO 2 at a low temperature of 160 °C, which can be attributed to the strong physical affinity of the WS 2 nanosheets to the NO 2 gas molecules. Importantly, by designing sensing experiments under different background gases, we found that WS 2 nanosheets do not require oxygen for NO 2 sensing, while oxygen is required for H 2 S sensing. Therefore, based on the adsorption and desorption and charge transfer between WS 2 nanosheets and adsorbed gas molecules, we propose different sensing mechanisms of WS 2 nanosheets for NO 2 and H 2 S sensing. [ABSTRACT FROM AUTHOR]

Sr[sub 4]Al[sub 14]O[sub 25]:Eu, Dy material with an extraordinarily long afterglow was synthesized via a traditional ceramic processing. Such a long afterglow observed can last over 20 h at recognizable intensity level (0.32 mcd/m²), which is attributed to energy exchange between the traps and emission states resulting from Dy and Eu doping. When the Eu[sup 2+] concentration doped in the host is less than 1.2 mol%, the emission spectra of Sr[sub 4]Al[sub 14]O[sub 25]:Eu, Dy show two main peaks at 407 and 494 nm, ascribed to two types of Eu[sup 2+] centers existing in the Sr[sub 4]Al[sub 14]O[sub 25] host. The emission peak at 407 nm disappears slowly with increasing concentration of Eu[sup 2+] due to the energy exchange between two types of Eu[sup 2+] centers. [ABSTRACT FROM AUTHOR]

The emergence of nanomaterials in the past decades has greatly advanced modern energy storage devices. Nanomaterials can offer high capacity and fast kinetics yet are prone to rapid morphological evolution and degradation. As a result, they are often hybridized with a stable framework in order to gain stability and fully utilize its advantages. However, candidates for such framework materials are rather limited, with carbon, conductive polymers, and Ti‐based oxides being the only choices; note these are all inactive or intercalation compounds. Conventionally, alloying‐/conversion‐type electrodes, which are thought to be electrochemically unstable by themselves, have never been considered as framework materials. This concept is challenged. Successful application of conversion‐type MnO nanorod as a anode framework for high‐capacity Mo2C/MoOx nanoparticles has been demonstrated in sodium‐ion batteries. Surprisingly, it can stably deliver 110 mAh g−1 under extremely high rate of 8000 mA g−1 (≈70 C) over 40 000 cycles with no capacity decay. More generally, this is considered as a proof of concept and much more alloying‐/conversion‐type materials are expected to be explored for such applications. [ABSTRACT FROM AUTHOR]

Discusses the use of plasma pyrolysis technology to prepare nanometer zinc oxide (ZnO). Technology's advantages for the preparation of various oxide powders; Characterization of the particle size, specific surface area and phase composition of the nanometer ZnO powders.

Abstract Multi-phase integration and structural hydration are effective material design strategies for advanced electrode materials with high capacity and fast lithiation. Herein, a novel layered-spinel lithium manganite hydrate is successfully synthesized through a one-step hydrothermal lithiation process. Structure characterizations, electrochemical properties, reaction mechanisms and kinetic analysis are investigated in detail. The layered-spinel coexistence, stable intercalated water, abundant interfaces/defects and mesoporous architectures comprising 2D nanosheets help to shorten the Li-ion transport pathway, promote electronic/ion conductivity, increase Li storage sites and maintain structural stability. With combined diffusion-controlled and pseudocapacitive reaction mechanisms, the layered-spinel lithium manganite hydrate exhibits superior electrochemical behaviors, showing great potentials for high-capability and ultrafast lithium storage. The comprehensive utilization of multi-phase integration and structural hydration promotes the diversity of material and structure systems, and further paves new way for the design of other high-performance electrode materials. Graphical abstract Image 1 Highlights • Lithium manganite hydrate exhibits high-capacity and ultrafast lithium storage. • The layered phase stabilized by interlayer water improves ionic transport kinetic. • The spinel phase with strong structural framework contributes to cycling stability. • Phase interfaces and structural disordering enhance capacity and cyclability. • Diffusion-controlled and pseudocapacitive reaction mechanisms are combined. [ABSTRACT FROM AUTHOR]

Based on the tungsten hydrate structure model, we report the strategy to fabricate hierarchically structured WO 3 ·0.33H 2 O/graphene composites through a facile hydrothermal approach. The structure characteristics, conversion reaction mechanism as well as the electrochemical properties are carefully investigated. The hierarchical architectures assembled by nanorods or nanobricks of about 20 nm thickness combine the advantages of reduced length scale of Li ion diffusion derived from nanosizes and structural stability guaranteed by hierarchical features. In addition, compared with bare WO 3 ·0.33H 2 O and anhydrous WO 3 , the WO 3 ·0.33H 2 O/graphene composites exhibit the optimal performances with high rate capability and good cycle stability, which is attributed to synergistic effects of structural hydration and graphene: providing a more open charge transfer channel, forming a conductive pathway and accommodating the volume change. Such an improved lithium storage performance makes the graphene-based WO 3 ·0.33H 2 O a promising anode candidate for lithium-ion battery applications. [ABSTRACT FROM AUTHOR]

A new pseudocapacitive nanocomposite is reported in this article. Such amorphous materials were prepared via restacking of Ni-Mn LDH and MnO 2 nanosheets obtained by exfoliation treatments. Synergetic effects of the two components were demonstrated in both alkaline and neutral aqueous electrolytes, as rate capability and cycle stability were both greatly improved compared to each-component samples and mixture. Tests on an activated carbon//nano-composite asymmetric device reveal that the energy density could be about 16 Wh/Kg at a power density of 15 KW/Kg in alkaline electrolytes, while in neutral electrolytes, the value reached about 13 Wh/Kg at a power density of 9 KW/Kg, matching with many other composition technologies. Besides, rather small leakage and self-discharge currents further indicate its promising applications in practical areas. [ABSTRACT FROM AUTHOR]

Spinel LiMn 2 O 4 is a promising cathode candidate for lithium ion batteries whose electrochemical properties strongly depend on the surface orientation. In this work, we have successfully synthesized a high crystalline and well-defined truncated octahedral LiMn 2 O 4 through the hydrothermal and heat treatment. The main {111} facets are aligned along the orientations mitigating Mn dissolution while the truncated {100} and {110} facets are along those facilitating Li + diffusion. Benefiting from the unique structure, the octahedral LiMn 2 O 4 delivers 143.4 mAh g −1 (close to the theoretical capacity of 148 mAh g −1 ) at 0.2 C and over 120 mAh g −1 at 30 C (discharged within 2 min) at 55 °C. Moreover, the fabricated LiMn 2 O 4 /Li 4 Ti 5 O 12 -TiO 2 full cell demonstrates 121.6 mAh g −1 at 1 C and 56.0 mAh g −1 at 30 C with ∼81.2% capacity retention following 1000 cycles. The facilely synthesized truncated octahedral LiMn 2 O 4 shows great potentials in practical applications for ultrafast and long-life lithium-ion batteries. [ABSTRACT FROM AUTHOR]

It is known that the exposed facet and defect state are crucial to the photocatalytic performance. Here, we report that the exposed facets of the building blocks in the tungsten oxide hierarchical nanostructures could be controlled by adjusting the amount of formamide in the hydrothermal precursor solution and the oxygen vacancies were successfully introduced through the post-air annealing. It is found that exposing high percentage (020) facet is unbeneficial for the photocatalytic performance and (200) and (002) facets should be the photocatalytic active facets of the hexagonal tungsten oxide. The hexagonal tungsten oxide with oxygen vacancies and maximum (200) and (002) facets archives highest photocatalytic performance in degrading rhodamine B under simulated solar light irradiation, which the rate constant per specific surface area (k/SBET) is 7.3 times as high as the sample without oxygen vacancies and minimum (200) and (002) facets. Both introducing oxygen vacancies and exposing (200) and (002) facets can enhance the separation efficiency of photo-generated charges, thus improving the photocatalytic performance. [ABSTRACT FROM AUTHOR]

The common one dimensional (1D) core-shell phase junction usually cannot fully utilize the separated charges because one phase is encapsulated inside, which leads to the incomplete release of the electrons or holes. Here, a unique vertical 1D/1D tungsten oxide phase junction constructed by orthorhombic WO 3 ·0.33H 2 O (o-WO 3 ·0.33H 2 O) nanorods and hexagonal WO 3 (h-WO 3 ) nanowires in the sunflower-like structure was fabricated via a facile one-step hydrothermal method. The nanorods and the nanowires vertically intersect at the endpoint to construct the vertical 1D/1D phase junction with another end exposed outside. This structure ensures that both two phases can contact the pollutants, so as to fully release the holes and electrons that accumulate on the o-WO 3 ·0.33H 2 O and h-WO 3 phase, respectively. Furthermore, the two phases are both single crystals, substantially decreasing the impediments of defects to the transport of the photogenerated charges. This novel hierarchical structure with vertical 1D o-WO 3 ·0.33H 2 O/h-WO 3 phase junction can significantly improve the utilization efficiency of the separated photogenerated charges and thus effectively enhance the photocatalytic performance. [ABSTRACT FROM AUTHOR]

A unique reduced graphene oxide (RGO) three-dimensionally wrapped WO 3 (WO 3 @RGO) composite was synthesized via a facile one-step hydrothermal method. In this composite, the building blocks of the WO 3 hierarchical structure, the nanobelts, were intimately wrapped by a layer of RGO. Due to the synergistic effect of the hierarchical structure of WO 3 and intimately wrapped RGO on the surface of the nanobelts, the WO 3 @RGO showed much higher photocatalytic performance in degrading rhodamine B and phenol under simulated solar light irradiation than the bare WO 3 and other composites in which only the mainframe of WO 3 was wrapped by RGO. Moreover, the photocatalytic activity was significantly influenced by the loading amount of RGO. The optimal performance was found in the 1.2% WO 3 @RGO, which was about 2.50 times that of the bare WO 3 . Conclusively, using graphene to wrap the building blocks rather than only the mainframe of semiconductors is anticipated to be a promising method to achieve high-performance photocatalysts for solar energy conversion. [ABSTRACT FROM AUTHOR]

Eight typical LiMnPO 4 nanocrystals with tunable morphologies have been controllably synthesized by varying the feeding sequence and the ratio of the reactants in an EG-assisted solvothermal approach. It is found that with the decrease of the OH − concentration induced by the primary LiOH/H 3 PO 4 ratio, the predominately exposed planes of LiMnPO 4 evolve from (010) for nanospindles to (100) for nanoplates in Li–P–Mn feeding sequence, and to both (010) and (100) for nanorods in Mn–P–Li feeding sequence. Further decrease of the OH − concentration hardly affects the formation of pure-phase LiMnPO 4 but results in significant changes in the morphology with distinctly increased particle size. The electrochemical properties of the corresponding LiMnPO 4 /C composites are remarkably dependent on their particle size. By applying the Mn–P–Li sequence and the LiOH/H 3 PO 4 ratio of 2.7–3.0, the as-prepared LiMnPO 4 /C nanorods exhibit superior rate capability (more than 105 mA h g −1 at 10 C) and remarkable cycling stability (a capacity retention of up to 93% after 100 cycles at 0.5 C) among all the samples, owing to their small length of less than 60 nm along the [010] direction. The results also confirm that excess LiOH amount is indeed required to yield LiMnPO 4 crystals with small particle size and attractive electrochemical properties. [ABSTRACT FROM AUTHOR]

Hierarchical tungsten oxide nanostructures, controllably assembled with one-dimensional nanosized building blocks, which exhibit different exposed facets and crystal phases were synthesized via a facile hydrothermal reaction assisted by urea. Systematic and comprehensive investigations indicate that urea plays a significant role in tuning the exposed facets of the building blocks and controlling the crystal phase by effectively regulating the process of nucleation. By adjusting the amount of urea, a suitable crystal phase can be obtained and the exposed facets can be tuned to achieve the highest photocatalytic activity of tungsten oxide. It has been found that (020) is the active facet of orthorhombic WO3·0.33H2O but not of hexagonal WO3. The orthorhombic WO3·0.33H2O exposing the largest amount of (020) facets shows the highest photocatalytic activity for the degradation of rhodamine B under visible light illumination, which is 4.1 times as high as that of the sample exposing the least amount of (020) facets. [ABSTRACT FROM AUTHOR]

Ni-Co layered double hydroxides (LDHs), as typical battery-type materials with high specific capacity and good rate property, have suffered poor cycle stability. In this work, we develop an in-situ synthesis method, which employs Ni foam as the substrate for crystal growth, simply by compensating a certain amount of hydroxyl in precursors before solvothermal reactions. Results prove that the sample prepared with hydroxyl compensation still exhibits relatively high specific capacity, about 170.6 mAh g −1 at 10 A g −1 and good capacity retention, about 63.2% when the current density is increased to 40 A g −1 . Especially, the cycle stability of the electrodes have been improved greatly, with about 99% capacity retention after cycling 3000 times. The improved cycle stability are competitive or superior to those of many other systems with more complicated modifications. Material characterizations indicate that the greatly enhanced cycle stability can be attributed to the strengthened connections between nanosheets and substrates and the inner structure stability of matrix, boned by sufficient hydroxyl. [ABSTRACT FROM AUTHOR]

Abstract: Reducing the particle size and coating conductive materials are both effective ways to improve the performance of LFP (LiFePO4). In this paper, we synthesized LFP/C/CPO (LiFePO4/C/CePO4) composites and investigated the effects of CePO4 modification on the morphologies and electrochemical properties of LFP/C composites. The results demonstrated that introducing CePO4 nanoparticles via in situ method could reduce the particle size significantly and improve the electrochemical properties of LFP/C. [Copyright &y& Elsevier]

Abstract: LiMn1−x Fe x PO4 nanomaterials at low Fe concentration (x = 0, 0.1, 0.2) for lithium-ion batteries have been synthesized with high yield via a facile solvothermal route in a mixed solvent of water and polyethylene glycol (PEG200). SEM and TEM images reveal that all samples are single crystalline with similar rod-like shapes, and XRD characterizations indicate that the crystal lattices decrease with the increasing concentration of Fe. Electrochemical tests show that the best electrochemical properties can be achieved by substituting 20% of Fe at Mn-site. The as-prepared LiMn0.8Fe0.2PO4 sample delivers a high initial discharge capacity of 165.3 mAh g−1 at 0.05C, which is close to the theoretical capacity of LiMnPO4. Moreover, it also demonstrates excellent cycle performance and remarkable rate capability. [Copyright &y& Elsevier]

As a typical metal oxide semiconductor, ZnO has been investigated deeply for the application of gas sensing materials. In this study, an ultrahigh sensitive and selective NO 2 gas sensor based on porous ZnO nanocubes derived from metal organic frameworks (MOFs) was reported. The MOF-derivatives were obtained by precisely control of the subsequent pyrolysis process. The sensitivity of MOF-derivatives toward 1 ppm NO 2 at 200 ºC was 51.41 under 500 ºC pyrolysis treatment. Compared with similar work, the sensitivity has been greatly improved. Furthermore, the fabricated gas sensor demonstrated excellent selectivity to NO 2 over other gases (CO, C 2 H 5 OH, H 2 , H 2 S, NO, NH 3). The ultrahigh sensitivity and selectivity were attributed to the unique structure after pyrolysis, which provides more exposed active sites and connected pore channels. • Porous and hollow ZnO nanocubes were prepared by pyrolysis of MOFs. • The reason for the difference of NO 2 sensitivity of MOF-derivatives at different pyrolysis temperatures was analyzed. • ZnO nanocubes under 500 ºC pyrolysis treatment exhibits excellent selectivity and sensitivity to 1 ppm NO 2 (51.41). [ABSTRACT FROM AUTHOR]