查看更多>>摘要：Silicon oxide(SiOx)has received remarkable attention as a next-generation battery material;however,the sudden decrease in the cycling retention constitutes a significant challenge in facilitating its application.Tris(2,2,2-trifluoroethyl)phosphite(TTFP),which can control parasitic reactions such as the pulverization of SiOx anode materials and electrolyte decomposition,has been proposed to improve the lifespan of the cell.The electro-chemical reduction of TTFP results in solid-electrolyte interphase(SEI)layers that are mainly composed of LiF,which occur at a higher potential than the working potential of the SiOx anode and carbonate-based solvents.The electrolyte with TTFP exhibited a substantial improvement in cycling retention after 100 cycles,whereas the standard electrolyte showed acutely decreased retention.The thickness of the SiOx anode with TTFP also changed only slightly without any considerable delamination spots,whereas the SiOx anode without TTFP was prominently deformed by an enormous volume expansion with several internal cracks.The cycled SiOx anode with TTFP exhib-ited less increase in resistance after cycling than that in the absence of TTFP,in addition to fewer decomposition adducts in corresponding X-ray photoelectron spectroscopy(XPS)analyses between the cycled SiOx anodes.These results demonstrate that TTFP formed SEI layers at the SiOx interface,which substantially reduced the pulveriza-tion of the SiOx anode materials;in addition,electrolyte decomposition at the interface decreased,which led to improved cycling retention.
查看更多>>摘要：Co3V2O8/Co3O4/Ti3C2Tx composite was easily synthesized via one-step succinct-operated hydrothermal process.The interconnected Co3V2O8/Co3O4 nanowires network can in-situ grow and anchor on the surface of Ti3C2Tx via the strong Co-F bonds and contribute tremendously to depress Ti3C2Tx self-restacking.Profiting from the synergistically interplayed effect among the multiple interfaces and high conductivity of Ti3C2Tx as well as outstanding stability of the as-designed nanostruc-ture,the optimum Co3V2O8/Co3O4/Ti3C2Tx electrode reaches a commendable specific capacitance(up to 3800 mF·cm-2),great rate capability(80％capacitance retention after 20-times current increasing),and preeminent cycling stability(95.4％/85.5％retention at 7000th/20,000th cycle).Moreover,the all-solid-state asymmetric supercapacitor based on Co3V2O8/Co3O4/Ti3C2Tx and active carbon can deliver a high energy density of 84.0 pWh·cm-2 at the power energy of 3.2 mW·cm-2,and excellent cycling durability with 87.0％of initial capacitance retention upon 20,000 loops.This work pro-vides a practicable pathway to tailor MXene-based com-posites for high-performance supercapacitor.
查看更多>>摘要：Garnet-type solid-state batteries(SSBs)are con-sidered to be one of the most promising candidates to realize next-generation lithium metal batteries with high energy density and safety.However,the dendrite-induced short-cir-cuit and the poor interfacial contact impeded the practical application.Herein,interface engineering to achieve low interfacial resistance without high temperature calcination was developed,which Li6.4La3Zr1.4Ta0.6O12(LLZTO)was simply coated with complex hydride(Li4(BH4)3I(3L1L))in various mass ratios n(Li4(BH4)3I)-(100-n)LLZTO(10 ≤ n≤ 40).The interfacial conductivity increases by more than three orders of magnitude from 8.29 × 10-6 S·cm-1 to 1.10 × 10-2 S.cm-1.Symmetric Li cells exhibit a high critical current density(CCD)of 4.0 mA·cm-2 and an excellent cycling stability for 200 h at 4.0 mA·cm-2.SSBs with polymeric sulfur-polyacrylonitrile(SPAN)cathode achieve a high discharge capacity of 1149 mAh·g-1 with a capacity retention of 91％after 100 cycles(0.2 C).This attempt guides a simple yet efficient strategy for obtaining a stable Li/LLZTO interface,which would promote the devel-opment of solid-state batteries.
查看更多>>摘要：Using coal gangue(CG)as raw material,a new type of all solid-waste-based 13-X molecular sieve material was controllably prepared by alkali fusion-hydrothermal method.The synthetic molecular sieve was used as a solid adsorbent to treat Cd2+-containing wastewater,and its adsorption behavior on Cd2+in aqueous solution was studied and analyzed.The microstructure and morphology of the molecular sieve were investigated by X-ray diffraction(XRD),field emission scanning electron microscopy(FESEM)and specific surface area analyzer.The results show that the synthesized 13-X molecular sieve has higher Brunauer-Emmett-Teller(BET)specific sur-face area with higher crystallinity and higher adsorption capacity for the heavy metal Cd2+.The adsorption process of Cd2+by molecular sieve conforms to the Langmuir isotherm adsorption equation and Lagergren pseudo-sec-ond-order rate equation.Combined with thermodynamic calculation,it can be concluded that the adsorption process is physically monolayer,spontaneous and exothermic.In this study,a low-cost and naturally available synthesis method of 13-X molecular sieve is reported.Combined with its adsorption mechanism for Cd2+,it provides a feasible and general method for removing heavy metal ions from coal gangue and also provides a new way for the utilization of coal gangue with high added value.
查看更多>>摘要：Paper-based sensing platform is a point of need analytical toolkit for safety testing.However,the sensi-tivity,specificity,and simplicity are still challenging.Herein,we report a novel strategy(Au/δ-MnO2 hollow nanosphere and 3,3',5,5'-tetramethylbenzidine(TMB)induced test strips for signal-on detection)that can be utilized for hexavalent chromium(Cr6+)detection.Inter-estingly,Cr6+(CrO42-)as a smart switch can remarkably enhance the oxidase-like activity of Au/δ-MnO2 hollow nanosphere.The presence of Cr6+can regulate the surface electronic redistribution of Au/δ-MnO2 and adjust the geometric configuration,which leads to the improvement in oxidase-like activity of Au/δ-MnO2.As a proof-of-concept application,a visual paper-based sensing platform of Cr6+along with quantitative analysis by the test strips was successfully constructed.This paper-based sensing platform exhibits a linear range with excellent selectivity for other interfering substances and lower limit of detection of 0.09 μmol·L-1,providing a promising toolkit at-home Cr6+measurement and environmental monitoring.
查看更多>>摘要：Chiral metamaterials(CMs)composed by arti-ficial chiral resonators have attracted great attentions in the recent decades due to their strong chiroptical resonance and identifiable interaction with chiral materials,facilitating practical applications in chiral biosensing,chiral emission,and display technology.However,the complex geometry of CMs improves the fabrication difficulty and hinders their scalable fabrication for practical applications,espe-cially in the visible and ultraviolet wavelengths.One potential strategy is the colloidal lithography that enables parallel fabrication for scalable and various planar struc-tures.Here,we demonstrate a stepwise colloidal lithogra-phy technique that uses sequential deposition from multiple CMs and expand their variety and complexity.The geometry and optical chirality of building blocks from single deposition are systematically investigated,and their combination enables a significant extension of the range of chiral patterns by multiple-step depositions.This approach resulted in a myriad of complex designs with different characteristic sizes,compositions,and shapes,which are particularly beneficial for the development of nanophotonic materials.In addition,we designed a flexible chiral device based on PDMS,which exhibits a good CD value and excellent stability even after multiple inward and outward bendings.The excellent compatibility to various substrates makes the planar CMs more flexible in practical applica-tions in microfluidic biosensing.
查看更多>>摘要：A red-emitting phosphor Ca2.91Si2O7∶0.09Eu3+with partial Al3+/P5+substitution on Si4+was synthesized via a simple solid-state method,and the effects of the introduction of the M3+/5+(M=Al,P)ions on the crystal structure and photoluminescence performance of Ca2.91Si2-xMxO7∶0.09Eu3+phosphors were investigated.The X-ray diffraction(XRD),energy-dispersive X-ray spectroscopy(EDS),and X-ray photoelectron spectroscopy(XPS)results revealed that the structure of Ca3Si2O7 remained the same after the introduction of Al3+and P5+ions.The characteristic emission of Eu3+-doped Ca3Si2_xMxO7 phosphors exhibited two main peaks at 617 nm(red)and 593 nm(orange)under excitation at 394 nm,which originated from the 5D0 → 7F2 and 5D0 → 7F1 electron transitions of Eu3+ions.After the partial substitution of Al3+and P5+,the red emission intensities of the Ca2.91Si2O7∶0.09Eu3+phosphors were significantly enhanced by 1.88-and 1.42-fold,respectively,which is attributed to the crystal-field effect around Eu3+.Meanwhile,the luminescence intensities of the Ca2.91Si1.96 Al0.04O7∶0.09Eu3+and Ca2.91Si1.94P0.06O7∶0.09Eu3+phos-phors at 210 ℃ were 79.36％and 77.53％of those at 30 ℃,respectively,indicating their excellent thermal sta-bility.Moreover,the as-prepared Ca2.91Si1.96A-l0.04O7∶0.09Eu3+and Ca2.91Si1.94P0.06O7∶0.09Eu3+red-emitting phosphors were combined with a near-ultraviolet chip of 395 nm to fabricate red-light-emitting diode(LED)and white(w)-LED devices with excellent chromaticity features.In summary,Al3+/P5+-substituted Ca2.91Si2O7∶0.09Eu3+can serve as red-emitting phosphors for appli-cations in w-LEDs.
查看更多>>摘要：The ceria-zirconia compound oxide-supported noble metal Pd(Pd@CZ)is widely used in three-way catalyst.Moreover,the surface structure of CZ plays an important role in catalytic activity of Pd.However,how to regulate the surface structure of CZ and clarify the struc-ture-activity relationship is still a challenge.In this paper,a strategy is proposed to develop high activity Pd@CZ nanocatalysts by tuning Y doping sites in CZ.The pre-cipitate-deposition method is developed to prepare the novel Ce0.485Zr0.485Y0.03O2 composite with surface doping of Y(CZ-Y-S).In addition,the Pd@CZ-Y-S(Pd supported on CZ-Y-S)exhibits superior catalytic activity for HC,CO,and NO oxide,wherein,for CO and C3H6 oxidation,the low-temperature activity of Pd@CZ-Y-S is still 20％higher than that of Pd@CZ-Y-B(Y bulk doping)and commercial Pd@CZ after 1000 ℃/4 h aging.The effect mechanism is further studied by density functional theory(DFT)calculation.Compared with Pd@CZ-Y-B,Pd@CZ-Y-S shows the lower CO oxide reaction energy barriers due to the weaker adsorption strength of O2.The Y surface doping strategy could provide valuable insights for the development of highly efficient Pd@CZ catalyst with extensive applications.
查看更多>>摘要：Developing fluorescence porous probe for detecting and eliminating Cu2+contamination in water or biosystem is an essential research project that has attracted considerable attention.However,improving the fluores-cence detecting efficiency while enhancing the adsorption capacity of the porous probe is of great challenge.Herein,a bifunctional two-dimensional imine-based porous covalent organic framework(TTP-COF)probe was designed and synthesized from 1,3,5-tris(4-aminophenyl)benzene(TAPB)and 2,4,6-Triformylphloroglucinol(TP)ligand.TTP-COF displayed rapid detection of Cu2+(limit of detection(LOD)=10 nmol·L-1 while achieving a high adsorption capacity of 214 mg·g-1(pH=6)at room temperature with high reusability(＞5 cycles).The key roles and contributions of high π-conjugate and delocalized electrons in TABP and functional-OH groups in TP were proved.More importantly,the fluorescence quenching mechanism of TTP-COF was studied by density functional theory theoretical calculations,revealing the crucial role of intramolecular hydrogen bonds among C=N and-OH groups and the blocking of the excited state intramolecular proton transfer process in detecting process of Cu2+.
查看更多>>摘要：The urgent demand of extreme(ultra-high/low)thermal conductivity materials is triggered by the high-power device,where exploring the theories and mecha-nisms of regulating thermal transport properties plays a key role.Herein,we elaborately investigate the effect of ver-tical(out-of-plane)piezoelectric characteristics on thermal transport,which is historically undiscovered.The different stacking-order(AA and AB)bilayer boron nitride(Bi-BN)in two-dimensional(2D)materials are selected as study cases.By performing state-of-the-art first-principles cal-culations,it is found that the polarization charge along the out-of-plane orientation ascends significantly with the increasing piezoelectric response in AB stacked Bi-BN(Bi-BN-AB)followed by the enhanced interlayer B-N atomic interactions.Consequently,the amplitude of pho-non anharmonicity in Bi-BN-AB increases larger than that in the AA stacked Bi-BN(Bi-BN-AA),resulting in the dramatic weakening of the thermal conductivity by 20.34％under 18％strain.Our research reveals the significant role of the vertical(out-of-plane)piezoelectric characteristic in regulating thermal transport and provides new insight into accurately exploring the thermal transport performance of 2D van der Waals materials.
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