The use of carbonized wood in various functional devices is attracting considerable attention due to its low cost,vertical channels,and high electrical conduction.However,the conventional carbonization method requires...The use of carbonized wood in various functional devices is attracting considerable attention due to its low cost,vertical channels,and high electrical conduction.However,the conventional carbonization method requires a long processing time and an inert atmosphere.Here,a microwave-assisted ultrafast carbonization technique was developed that carbonizes natural wood in seconds without the need for an inert atmosphere,and the obtained aligned-porous carbonized wood provided an excellent electrochemical performance as an anode material for lithium-ion batteries.This ultrafast carbonization technique simultaneously produced ZnO nanoparticles during the carbonization process that were uniformly distributed on the alignedporous carbon.The hierarchical structure of carbonized wood functionalized with ZnO nanoparticles was used as a host for achieving high-performance lithium-sulfur batteries:the highly conductive carbonized wood framework with vertical channels provided good electron transport pathways,and the homogeneously dispersed ZnO nanoparticles effectively adsorbed lithium polysulfide and catalyzed its conversion reactions.In summary,a new method was developed to realize the ultrafast carbonization of biomass materials with decorated metal oxide nanoparticles.展开更多
Understanding how defect chemistry of oxide material influences the thermal stability of noble metal dopant ions plays an important role in designing high-performance heterogeneous catalytic systems.Here we use in-sit...Understanding how defect chemistry of oxide material influences the thermal stability of noble metal dopant ions plays an important role in designing high-performance heterogeneous catalytic systems.Here we use in-situ ambient-pressure X-ray photoemission spectroscopy(APXPS)to experimentally determine the role of grain boundary in the thermal stability of platinum doped cerium oxide(Pt/CeO_(2)).The grain boundaries were introduced in Pt/CeO_(2)thin films by pulsed laser deposition without significantly change of the surface microstructure.The defect level was tuned by the strain field obtained using a highly/low mismatched substrate.The Pt/CeO_(2)thin film models having well defined crystallographic properties but different grain boundary structural defect levels provide an ideal platform for exploring the evolution of Pt–O–Ce bond with changing the temperature in reducing conditions.We have direct demonstration and explanation of the role of Ce^(3+)induced by grain boundaries in enhancing Pt2+stability.We observe that the Pt^(2+)–O–Ce^(3+)bond provides an ideal coordinated site for anchoring of Pt^(2+)ions and limits the further formation of oxygen vacancies during the reduction with H_(2).Our findings demonstrate the importance of grain boundary in the atomic-scale design of thermally stable catalytic active sites.展开更多
Garnet-type oxide solid electrolytes are the critical materials for all-solid-state lithium ion batteries.Nanoscale spectroscopic analysis on solid electrolytes plays a key role in bridging the gap between microstruct...Garnet-type oxide solid electrolytes are the critical materials for all-solid-state lithium ion batteries.Nanoscale spectroscopic analysis on solid electrolytes plays a key role in bridging the gap between microstructure and properties.In this work,Auger electron spectroscopy(AES),which can directly detect lithium element and distinguish its valence state,was applied to characterize the garnet-type Li_(6.4)La_(3)Zr_(1.4)Ta_(0.6O12)(LLZTO).Different spectroscopy parameters were evaluated and optimal acquisition conditions were provided.Electron induced precipitation of lithium metal from LLZTO was observed.By exploring the influence factors of precipitation and combining transmission electron microscopy(TEM)and focused ion beam(FIB)experiments,the underlying mechanism of the phenomenon was revealed and previous controversy was resolved.The analysis method was also extended to other types of solid electrolytes,and this work provides a reference for future in-depth research on the structure-property relationship of solid electrolytes using AES.展开更多
Garnet-type oxide is one of the most promising solid-state electrolytes(SSEs)for solid-state lithium-metal batteries(SSLMBs).However,the Li dendrite formation in garnet oxides obstructs the further development of the ...Garnet-type oxide is one of the most promising solid-state electrolytes(SSEs)for solid-state lithium-metal batteries(SSLMBs).However,the Li dendrite formation in garnet oxides obstructs the further development of the SSLMBs seriously.Here,we report a high-performance garnet oxide by using AlN as a sintering additive and Li as an anode interface layer.AlN with high thermal conductivity can promote the sintering activity of the garnet oxides,resulting in larger particle size and higher relative density.Moreover,Li3N with high ionic conductivity formed at grain boundaries and interface can also improve Li-ion transport kinetics.As a result,the garnet oxide electrolytes with AlN show enhanced thermal conductivity,improved ionic conductivity,reduced electronic conductivity,and increased critical current density(CCD),compared with the counterpart using Al_(2)O_(3) sintering aid.In addition,Li symmetric cells and Li|LiFePO_(4)(Li|LFP)half cells using the garnet electrolyte with the AlN additive exhibit good electrochemical performances.This work provides a simple and effective strategy for high-performance SSEs.展开更多
Despite the unique properties of bismuth(Bi),there is a lack of two-dimensional(2D)heterostructures between Bi and other functional 2D materials.Here,a coherent strategy is reported to simultaneously synthesize rhombo...Despite the unique properties of bismuth(Bi),there is a lack of two-dimensional(2D)heterostructures between Bi and other functional 2D materials.Here,a coherent strategy is reported to simultaneously synthesize rhombohedral phase Bi nanoflakes and bismuth oxychloride(BiOCI)nanosheets.The delicate balance between several reactions is mediated mainly for the reduction and chlorination in the chemical vapor transport(CVT)process.The Bi-BiOCI lateral heterostructures have been constructed via the coalescence of the two different 2D nanostructures.The characteristics of ambipolar conducting Bi and insulator-like BiOCI are elaborated by scanning microwave impedance microscopy(sMIM).This work demonstrates a way to construct a 2D Bi nanostructure in junction with its oxyhalide.展开更多
基金supported by the National Natural Science Foundation of China (No.52222311)the Shanghai RisingStar Program (20QA1406600)+2 种基金ChEM,SPST of Shanghai Tech University (#EM02161943)Shanghai Science and Technology Plan (21DZ2260400)Double First-Class Initiative Fund of Shanghai Tech University for supporting
文摘The use of carbonized wood in various functional devices is attracting considerable attention due to its low cost,vertical channels,and high electrical conduction.However,the conventional carbonization method requires a long processing time and an inert atmosphere.Here,a microwave-assisted ultrafast carbonization technique was developed that carbonizes natural wood in seconds without the need for an inert atmosphere,and the obtained aligned-porous carbonized wood provided an excellent electrochemical performance as an anode material for lithium-ion batteries.This ultrafast carbonization technique simultaneously produced ZnO nanoparticles during the carbonization process that were uniformly distributed on the alignedporous carbon.The hierarchical structure of carbonized wood functionalized with ZnO nanoparticles was used as a host for achieving high-performance lithium-sulfur batteries:the highly conductive carbonized wood framework with vertical channels provided good electron transport pathways,and the homogeneously dispersed ZnO nanoparticles effectively adsorbed lithium polysulfide and catalyzed its conversion reactions.In summary,a new method was developed to realize the ultrafast carbonization of biomass materials with decorated metal oxide nanoparticles.
基金partially supported by Shanghai Rising-Star Program(20QA1406600)the Centre for High-resolution Electron Microscopy(CℏEM)+2 种基金School of Physical Science and Technology,ShanghaiTech University(EM02161943)Shanghai Science and Technology Plan(21DZ2260400)Double-Class Initiative Fund of ShanghaiTech University for support。
基金The APXPS experiments were performed at BL02B01 of SSRF with the approval of the Proposal Assessing Committee of SiP.ME2 platform project(Proposal No.2019-SSRF-PT-011613)the Natural Science Foundation of China(No.11227902)the Shanghai Key Research Program(No.20ZR1436700).
文摘Understanding how defect chemistry of oxide material influences the thermal stability of noble metal dopant ions plays an important role in designing high-performance heterogeneous catalytic systems.Here we use in-situ ambient-pressure X-ray photoemission spectroscopy(APXPS)to experimentally determine the role of grain boundary in the thermal stability of platinum doped cerium oxide(Pt/CeO_(2)).The grain boundaries were introduced in Pt/CeO_(2)thin films by pulsed laser deposition without significantly change of the surface microstructure.The defect level was tuned by the strain field obtained using a highly/low mismatched substrate.The Pt/CeO_(2)thin film models having well defined crystallographic properties but different grain boundary structural defect levels provide an ideal platform for exploring the evolution of Pt–O–Ce bond with changing the temperature in reducing conditions.We have direct demonstration and explanation of the role of Ce^(3+)induced by grain boundaries in enhancing Pt2+stability.We observe that the Pt^(2+)–O–Ce^(3+)bond provides an ideal coordinated site for anchoring of Pt^(2+)ions and limits the further formation of oxygen vacancies during the reduction with H_(2).Our findings demonstrate the importance of grain boundary in the atomic-scale design of thermally stable catalytic active sites.
基金supported by the Shanghai Science and Technology Plan(No.21DZ2260400)the startup funding from ShanghaiTech University.The electron microscopy characterization was supported by the Center for High-resolution Electron Microscopy(CћEM)at ShanghaiTech University。
文摘Garnet-type oxide solid electrolytes are the critical materials for all-solid-state lithium ion batteries.Nanoscale spectroscopic analysis on solid electrolytes plays a key role in bridging the gap between microstructure and properties.In this work,Auger electron spectroscopy(AES),which can directly detect lithium element and distinguish its valence state,was applied to characterize the garnet-type Li_(6.4)La_(3)Zr_(1.4)Ta_(0.6O12)(LLZTO).Different spectroscopy parameters were evaluated and optimal acquisition conditions were provided.Electron induced precipitation of lithium metal from LLZTO was observed.By exploring the influence factors of precipitation and combining transmission electron microscopy(TEM)and focused ion beam(FIB)experiments,the underlying mechanism of the phenomenon was revealed and previous controversy was resolved.The analysis method was also extended to other types of solid electrolytes,and this work provides a reference for future in-depth research on the structure-property relationship of solid electrolytes using AES.
基金the National Key R&D Program of China(No.2019YFA0210600)the National Natural Science Foundation of China(No.21805185)+2 种基金Shanghai Science and Technology Plan(No.21DZ2260400)Shanghai Rising-Star Program(No.20QA1406600)Center for High-resolution Electron Microscopy,SPST of ShanghaiTech University(No.EM02161943)for support.
文摘Garnet-type oxide is one of the most promising solid-state electrolytes(SSEs)for solid-state lithium-metal batteries(SSLMBs).However,the Li dendrite formation in garnet oxides obstructs the further development of the SSLMBs seriously.Here,we report a high-performance garnet oxide by using AlN as a sintering additive and Li as an anode interface layer.AlN with high thermal conductivity can promote the sintering activity of the garnet oxides,resulting in larger particle size and higher relative density.Moreover,Li3N with high ionic conductivity formed at grain boundaries and interface can also improve Li-ion transport kinetics.As a result,the garnet oxide electrolytes with AlN show enhanced thermal conductivity,improved ionic conductivity,reduced electronic conductivity,and increased critical current density(CCD),compared with the counterpart using Al_(2)O_(3) sintering aid.In addition,Li symmetric cells and Li|LiFePO_(4)(Li|LFP)half cells using the garnet electrolyte with the AlN additive exhibit good electrochemical performances.This work provides a simple and effective strategy for high-performance SSEs.
基金the major research-based facility platforms at ShanghaiTech University,including the Analytical Instrum entation Center(SPST-AIC10112914)the Centre for High-Resolution Electron Microscopy(CnEM-EM02161943)Soft Matter Nanofab(SMN180827).We acknowledged Prof.Xue(ShanghaiTech,SPST)for the MoS_(2) sample.This work was funded by ShanghaiTech University(Wang start-up and SM N180827).
文摘Despite the unique properties of bismuth(Bi),there is a lack of two-dimensional(2D)heterostructures between Bi and other functional 2D materials.Here,a coherent strategy is reported to simultaneously synthesize rhombohedral phase Bi nanoflakes and bismuth oxychloride(BiOCI)nanosheets.The delicate balance between several reactions is mediated mainly for the reduction and chlorination in the chemical vapor transport(CVT)process.The Bi-BiOCI lateral heterostructures have been constructed via the coalescence of the two different 2D nanostructures.The characteristics of ambipolar conducting Bi and insulator-like BiOCI are elaborated by scanning microwave impedance microscopy(sMIM).This work demonstrates a way to construct a 2D Bi nanostructure in junction with its oxyhalide.
