Facile preparation of core-shell Si@Li4Ti5O12 nanocomposite as large-capacity lithium-ion battery anode

As a promising alternative anode material,silicon(Si)presents a larger capacity than the commercial anode to achieve large capacity lithium-ion batteries.However,the application of pure Si as anode is hampered by limitations such as volume expansion,low conductivity and unstable solid electrolyte interphase.To break through these limitations,the core-shell Si@Li4Ti5O12nanocomposite,which was prepared via in-situ self-assembly reaction and decompressive boiling fast concentration method,was proposed in this work.This anode combines the advantages of nano-sized Si particle and pure Li4Ti5O12(LTO)coating layer,improving the performance of the lithium-ion batteries.The Si@Li4Ti5O12 anode displays a high initial discharge/charge specific capacity of 1756/1383 m Ahg^-1 at 500 mAg^-1(representing high initial coulombic efficiency of 78.8%),a large rate capability(specific capacity of 620 mAhg^-1 at4000 mAg^-1),an outstanding cycling stability(reversible specific capacity of 883 mAhg^-1 after 150 cycles)and a low volume expansion rate(only 3.3% after 150 cycles).Moreover,the synthesis process shows the merits of efficiency,simplicity,and economy,providing a reliable method to fabricate large capacity Si@Li4Ti5O12nanocomposite anode materials for practical lithium-ion batteries.

A Local Reference Frame Construction Method Based on the Signed Surface Variation

A fast local reference frame(LRF)construction method based on the signed surface variation is proposed,which can adapt to the real-time applications such as self-driving,face recognition,object detection.The z-axis of the LRF is generated based on the concavity of the local surface of keypoint.The x-axis is constructed by the weighted vector sum of a set of projection vectors of the local neighborhoods around keypoint.The performance of the proposed LRF is evaluated on six standard datasets and compared with six state-of-the-art LRF construction methods(e.g.,BOARD,FLARE,SHOT,RoPS and TOLDI).Experimental results validate the high repeatability,robustness,universality and time efficiency of our method.

In-situ construction of all-scale hierarchical microstructure and thermoelectric properties of(Sr_(0.25)Ca_(0.25)Ba_(0.25)La_(0.25))TiO_(3)/Pb@Bi composite oxide ceramics

SrTiO_(3)-based oxides have been investigated as a promising n-type thermoelectric material at high temperatures;however,the relatively high thermal conductivity results in inferior thermoelectric performance.The lattice thermal conductivity can be significantly reduced by high-entropy engineering via severe lattice distortion.However,high configuration entropy also causes the deterioration of carrier mobility and restrains electron transport resulting in low electrical conductivity.In this work,the low lattice thermal conductivity of 1.7 W/(m·K)at 1073 K and significantly improved electrical conductivity of 112 S/cm from 60 S/cm can be achieved in n-type(Sr_(0.25)Ca_(0.25)Ba_(0.25)La_(0.25))TiO_(3)/Pb@Bi composites ceramics with core-shell grains of all-scale hierarchical microstructure.The effects of the complex microstructure of core-shell grains as well as the precipitated Pb@Bi particles on electrons and phonons transport properties were systematically explored.ZTmax of 0.18 was obtained for the SPS-1200,which was 1.5 times that of pure high-entropy(Ca_(0.2)Sr_(0.2)Ba_(0.2)La_(0.2)Pb_(0.2))TiO_(3)samples prepared by a solid-state method.This improvement in thermoelectric performance contributes to the addition of Bi_(2)O_(3)into the high-entropy(Sr_(0.2)Ca_(0.2)Ba_(0.2)Pb_(0.2)La_(0.2))TiO_(3)matrix resulting in multiphase core-shell grain structure combined with well-dispersed nano-sized metal Pb@Bi precipitates in the matrix.This feasible strategy of in-situ constructing all-scale hierarchical nanostructures can also be applied to enhance the performance of other thermoelectric systems.

Ultra-fast charge-discharge and high-energy storage performance realized in K_(0.5)Na_(0.5)NbO_(3)-Bi(Mn_(0.5)Ni_(0.5))O_(3) ceramics

Lead-free relaxor ceramics(1−x)K_(0.5)Na_(0.5)NbO_(3)−xBi(Mn_(0.5)Ni_(0.5))O_(3)((1−x)KNN-xBMN)with considerable charge-discharge characteristics and energy storage properties were prepared by a solid state method.Remarkable,a BMN doping level of 0.04,0.96KNN-0.04BMN ceramic obtained good energy storage performance with acceptable energy storage density Wrec of 1.826 J/cm^(3) and energy storage efficiencyηof 77.4%,as well as good frequency stability(1-500 Hz)and fatigue resistance(1-5000 cycles).Meanwhile,a satisfactory charge-discharge performance with power density PD~98.90 MW/cm^(3),discharge time t0.9<70 ns and temperature stability(30-180°C)was obtained in 0.96KNN-0.04BMN ceramic.The small grain size(~150 nm)and the high polarizability of Bi3+are directly related to its good energy storage capacity.This work proposes a feasible approach for lead-free KNN-based ceramics to achieve high-energy storage and ultra-fast charge-discharge performance as well as candidate materials for the application of advanced high-temperature pulse capacitors.

Liver Stiffness Measurement Can Reflect the Active Liver Necroinflammation in Population with Chronic Liver Disease:A Real-world Evidence Study

Background and Aims: Non-invasive evaluation of liver nec-roinflammation in patients with chronic liver disease is an un-met need in clinical practice.The diagnostic accuracy of transient elastography-based liver stiffness measurement(LSM)for liver fibrosis could be affected by liver necroinflam-mation,the latter of which could intensify stiffness of the liver.Such results have prompted us to explore the diagnosis potential of LSM for liver inflammation.Methods: Three cross-sectional cohorts of liver biopsy-proven chronic liver dis-ease patients were enrolled,including 1417 chronic hepatitis B(CHB)patients from 10 different medical centers,106 non-al-coholic steatohepatitis patients,and 143 patients with auto-immune-related liver diseases.Another longitudinal cohort of 14 entecavir treatment patients was also included.The re-ceiver operating characteristic(ROC)curve was employed to explore the diagnostic value of LSM.Results: In CHB patients,LSM value ascended with the increased severity of liver nec-roinflammation in patients with the same fibrosis stage.Such positive correlation between LSM and liver necroinflammation was also found in non-alcoholic steatohepatitis and autoim-mune-related liver diseases populations.Furthermore,the ROC curve exhibited that LSM could identify moderate and se-vere inflammation in CHB patients(area under the ROC curve as 0.779 and 0.838)and in non-alcoholic steatohepatitis pa-tients(area under the ROC curve as 0.826 and 0.871),respec-tively.Such moderate diagnostic value was also found in autoimmune-related liver diseases patients.In addition,in the longitudinal entecavir treated CHB cohort,a decline of LSM values was observed in parallel with the control of inflam-matory activity in liver.Conclusions: Our study implicates a diagnostic potential of LSM to evaluate the severity of liver necroinflammation in chronic liver disease patients.

Low temperature catalytic oxidation of NO over different-shaped CeO2

To investigate the effect of CeOnanomaterial morphology on its performance for NO catalytic oxidation.Three kinds of CeOnanomaterials including CeOnanorods,nanospheres and nanoparticles were prepared by hydrothermal method and used for catalytic oxidation of NO at low temperature. The experimental results show that CeOnanorods are of the best catalytic performance. Characterization techniques including TEM, XRD, H-TPR, NO-TPD and XPS were used to determine the relationship between the morphology of CeOnanomaterial and its catalytic performance. TEM images show that CeOnanorods predominantly exposed(110) and(10 0) planes, while CeOnanospheres and CeOnanoparticles predominantly exposed(111) plane. The excellent catalytic performance of CeOnanorods could be ascribed to the low crystallinity, high reducibility, strong NO adsorption ability and the presence of more surface chemisorbed oxygen.

PHASE-FIELD SIMULATION FOR MICROSTRUCTURAL DEVELOPMENT OF TEXTURED CERAMICS PREPARED BY REACTION TEMPLATED GRAIN GROWTH

A modified model using phase-field method in order to describe the microstructural development for the reaction templated grain growth process was developed.The current model well expressed anisotropic enlargement of the template particles.The initial parameters such as the matrix particles size,the template particles size,fraction,aspect ratio of the template particles and porosity were examined.The simulation results show that the fraction of oriented grains increases with decreasing the matrix particles size and porosity,and increasing the fraction of the initial template particles.An increase for the aspect ratio of template particles gives rise to the anisotropic microstructure development.The study suggests that the simulation results would give a guiding principle in terms of the initial preparation conditions for the textured ceramics having both a large fraction of oriented grains and anisotropic microstructure.