Ameliorating the interfacial issues of all-solid-state lithium metal batteries by constructing polymer/inorganic composite electrolyte

Lithium metal is one of the most promising anodes for next-generation batteries due to its high capacity and low reduction potential.However,the notorious Li dendrites can cause the short life span and safety issues,hindering the extensive application of lithium batteries.Herein,Li_(7)La_(3)Zr_(2)O_(12)(LLZO)ceramics are integrated into polyethylene oxide(PEO)to construct a facile polymer/inorganic composite solid-state electrolyte(CSSE)to inhibit the growth of Li dendrites and widen the electrochemical stability window.Given the feasibility of our strategy,the designed PEO-LLZO-LiTFSI composite solid-state electrolyte(PLLCSSE)exhibits an outstanding cycling property of 134.2 mAh g^(-1) after 500 cycles and the Coulombic efficiency of 99.1%after 1000 cycles at 1 C in LiFePO_(4)-Li cell.When cooperated with LiNi_(0.6)Co_(0.2)Mn_(0.2)O_(2)(NCM622)cathode,the PLL-CSSE renders a capacity retention of 82.4%after 200 cycles at 0.2 C.More importantly,the uniform dispersion of LLZO in PEO matrix is tentative tested via Raman and FT-IR spectra and should be responsible for the improved electrochemical performance.The same conclusion can be drawn from the interface investigation after cycling.This work presents an intriguing solid-state electrolyte with high electrochemical performance,which will boost the development of all-solid-state lithium batteries with high energy density.

Modeling the effect of uniform and nonuniform dispersion of nanofillers on electrical tree propagation in polyethylene dielectric

A phase-field model is developed in this paper based on the similarity between mechanical fracture and dielectric breakdown.Electrical treeing is associated with the dielectric breakdown in solid dielectrics by the application of high voltages.Instead of explicitly tracing the propagation of conductive channel,this model initializes a continuous phase field to characterize the extent of damage.So far,limited research has been conducted for simulating the effect of nanofiller dispersion on electrical treeing.No study has modeled the effect of uniform and nonuniform dispersion of nanofillers with varying filler concentration on treeing.Since electrical treeing tends to decrease the breakdown strength of solid dielectrics therefore,nanofillers are widely used to distract the tree from a straight channel to distribute its energy in multiple paths.Diverting a straight treeing channel into mul-tiple paths reduces the chances of its propagation from live to dead-end hence,improving the breakdown strength.The physical and chemical nature of nanofillers has a crucial impact on increasing the resistance to treeing.In this paper,phase-field model is developed and used to simulate electrical treeing in polyethylene for varying concentrations of alumina nanofiller using COM-SOL Multiphysics.Tree inception time,tree-growth patterns,and corresponding changes in dielectric strength is studied for both dispersions.Electrical treeing under different concentrations of alumina nanofillers with uniform and nonuniform dispersion is investigated in polyethylene as a base material.It is observed that fillers with uniform dispersion increases the resistance to tree-ing and tree inception time.Highest resistance to treeing is observed by adding 1%nanoalumina uniformly in raw polyethylene.Moreover,in uniform dispersion the tree deflects into multiple branches earlier than nonuniform dispersion impeding the damage speed as well.

Construction of Fe/Ag galvanic couple by mechanochemical in-situ reduced Ag to accelerate the degradation of Fe-based implant

Orthopedic applications of Fe have been hindered by the insufficient degradation rate.Alloying with noble elements(such as Ag,Au,and Pt)to generate galvanic couples is a feasible approach.However,the direct preparation of homogenous alloys by mechanical alloying or metallurgy is difficult because of the differences in strength,density,and toughness.In this study,Ag_(2)O was selected as the precursor phase for incorporation into Fe to achieve a homogeneous distribution of Ag,which was then reduced in situ to Ag via a mechanochemical reduction reaction during mechanical alloying.The composite powders were printed as implants by selective laser melting,where a fast cooling rate contributed to the retention of the phase distribution of the obtained powder.The electrochemical tests showed that the Fe-Ag_(2)O implant had a high corrosion current density(21.88±0.12μA/cm^(2))and instantaneous corrosion rate(0.23±0.05 mm/year).Moreover,the implant exhibited a faster degradation rate(0.22 mm/year)than Fe(0.15 mm/year)and Fe-Ag(0.21 mm/year)after immersion for 28 d.The acceleration mechanism of the implant could be attributed to the uniformly distributed Ag particles triggering many galvanic couples with the Fe grains,which was confirmed by the observation of the corrosion surface.In addition,the composite implants exhibited good biocompatibility and antibacterial properties.

Physical modelling of particle transport phenomenon and vibration behavior of converter with bottom powder injection

A cold model of top-bottom blown converter was set up to study the particle transport phenomenon and vibration performance of converter with bottom powder injection.The effect of bottom blowing flow rates,tuyere diameters,arrangements,and powder to gas mass ratios on powder distribution and furnace body vibration was investigated.The results show that the bottom injection parameters and modes have significant effects on the particle transport behavior and furnace vibration.The powder dispersion uniformity and furnace vibration increase with the increase in bottom blowing tuyere diameters.In the lower range of bottom blowing flow rates and powder to gas mass ratios,the powder dispersion uniformity is improved with the increase in them.However,in the higher range,the excessive furnace vibration leads to reduction in uniformity in powder dispersion.When the bottom blowing tuyeres arrange at double arrangement of 0.5R(R refers to the radius of the bottom)distance between tuyere and center of bath bottom,the converter has optimal particle transport behavior and vibration performance.The vibration law of converter with bottom powder injection was revealed by deducing the empirical formulas of furnace vibration maximum amplitude.The vibration intensity is affected by Froude number,powder to gas mass ratio,and tuyere arrangement.

Enhanced photoluminescence property of sulfate ions modified YAG:Ce^(3+) phosphor by co-precipitation method

The sulfate ions modified YAG：Ce^（3＋） phosphors were prepared by co-precipitation method and characterized by X-ray diffraction,transmission electron microscopy,and photoluminescence.Effects of sulfate ions on the photoluminescence（PL） property of the as-prepared YAG：Ce^（3＋） phosphors were studied,with sodium dodecyl sulfate（SDS） being added to R^（3＋）（Ce^（3＋）,Y^（3＋）,Al^（3＋）） ions.Results indicated that pure YAG：Ce^（3＋） phosphors with different ratios of sulfate ions could be easily obtained by calcining the as-synthesized precursor at 950 ℃ for 2 h,the YAG：Ce^（3＋） phosphors with an optimal mass ratio of 3.5 wt.%SDS had the highest emission intensity and the best dispersion behavior,and the fluorescence decay of the as-obtained YAG：Ce^（3＋） phosphors was related to the lattice defect,reabsorption and cross correlation.Furthermore,thermal quenching properties of the YAG：Ce^（3＋） phosphors and the YAG：Ce^（3＋） phosphors with 3.5 wt.%SDS were also discussed,indicating that the YAG：Ce^（3＋） with SDS phosphors could have potential applications in the daylight LEDs or warm white LEDs.

Nanocluster PtNiP supported on graphene as an efficient electrocatalyst for methanol oxidation reaction

In this study,phosphorus doped graphene supported PtNiP nanocluster electrocatalyst(PtNiP/P-graphene)was successfully prepared via a simple hypophosphite-assisted co-reduction method.The improved anchoring force and increased anchoring sites of graphene support result from phosphorus doping as well as size-confined growth effect of NaH_(2)PO_(2) leads to uniform dispersion of ultrafine PtNiP nanoclusters.Doped P also promotes the removal of CO-like intermediate by adjusting Pt electronic structure combining with alloyed Ni via electronic effects.As a result,the as-prepared PtNiP/P-graphene catalyst with more exposed active sites and optimized electronic structure of Pt alloy shows excellent electrocatalytic performances for methanol oxidation reaction(MOR)both in activity and durability in an acidic medium.

Three dimensional microstructures and wear resistance of Al-Bi immiscible alloys with different grain refiners

The three dimensional(3D) microstructures of Al-Bi alloys with different grain refiners(Al-5Ti-B, Al-3B and Al-3Ti) have been studied using synchrotron X-ray microtomography. The relationships between the microstructures and the corresponding wear behavior are verified through the friction and wear tests. The worn surfaces of the samples with grain refiners tested under 15 and 60 N loads are analyzed using Scanning Electron Microscopy(SEM). The results indicate that the addition of grain refiners is beneficial to the size and distribution of the Bi-rich particles in Al-Bi alloys. Compared with Al-5Ti-B and Al-3B grain refiners, the Bi-rich particles are more uniformly distributed and spherical with finer size with the addition of Al-3Ti grain refiner. The refinement renders the Al-20wt%Bi alloy refined by Al-3Ti the superior wear resistance with respect to those refined by Al-5Ti-B and Al-3B grain refiners, corresponding to the microstructures with fine and uniformly distributed Bi-rich particles in the Al matrix.

Structure and photoluminescence properties of InN films grown on porous silicon by MOCVD

In this work, indium nitride(InN) films were successfully grown on porous silicon(PS) using metal oxide chemical vapor deposition(MOCVD) method. Room temperature photoluminescence(PL) and field emission scanning electron microscopy(FESEM) analyses are performed to investigate the optical, structural and morphological properties of the InN/PS nanocomposites. FESEM images show that the pore size of InN/PS nanocomposites is usually less than 4 μm in diameter, and the overall thickness is approximately 40 μm. The InN nanoparticles penetrate uniformly into PS layer and adhere to them very well. Nitrogen(N) and indium(In) can be detected by energy dispersive spectrometer(EDS). An important gradual decrease of the PL intensity for PS occurs with the increase of oxidation time, and the PL intensity of PS is quenched after 24 h oxidization. However, there is a strong PL intensity of InN/PS nanocomposites at 430 nm(2.88 eV), which means that PS substrate can influence the structural and optical properties of the InN, and the grown InN on PS substrate has good optical quality.