In recent years,aqueous aluminum ion batteries have been widely studied owing to their abundant energy storage and high theo retical capacity.An in-depth study of vanadium oxide materials is necessary to address the p...In recent years,aqueous aluminum ion batteries have been widely studied owing to their abundant energy storage and high theo retical capacity.An in-depth study of vanadium oxide materials is necessary to address the precipitation of insoluble products covered cathode surface and the slow reaction kinetics.Therefore,a method using a simple one-step hydrothermal preparation and oxalic acid to regulate oxygen vacancies has been reported.A high starting capacity(400 mAh g^(-1))can be achieved by Ov-V2O5,and it is capable of undergoing 200 cycles at 0.4 A g^(-1),with a termination discharge capacity of103 mAh g^(-1).Mechanism analysis demonstrated that metastable structures(AlxV2O5and HxV2O5)were constructed through the insertion of Al^(3+)/H^(+)during discharging,which existed in the lattice intercalation with V2O5.The incorporation of oxygen vacancies lowers the reaction energy barrier while improving the ion transport efficiency.In addition,the metastable structure allows the electrostatic interaction between Al3+and the main backbone to establish protection and optimize the transport channel.In parallel,this work exploits ex-situ characterization and DFT to obtain a profound insight into the instrumental effect of oxygen vacancies in the construction of metastable structures during in-situ electrochemical activation,with a view to better understanding the mechanism of the synergistic participation of Al3+and H+in the reaction.This work not only reports a method for cathode materials to modulate oxygen vacancies,but also lays the foundation for a deeper understanding of the metastable structure of vanadium oxides.展开更多
Surface structures and properties of Sn islands grown on superconducting substrate 2H-NbSe2（0001）are studied using low temperature scanning tunneling microscopy or spectroscopy.The pure face-centered cubic（fee）str...Surface structures and properties of Sn islands grown on superconducting substrate 2H-NbSe2（0001）are studied using low temperature scanning tunneling microscopy or spectroscopy.The pure face-centered cubic（fee）structure of Sn surface is obtained.Superconductivity is also detected on the fcc-Sn（111）surface,and the size of superconducting gap on the Sn surface is nearly the same as that on the superconducting substrate.Furthermore,phase transition occurs from fcc-Sn（111）toβ-Sn（001）by keeping the sample at room temperature for a certain time.Due to the strain relaxation on theβ-Sn islands,both the in-plane unit cell and out-of-plane structures distort,and the height of surface atoms varies periodically to form a universal ripple structure.展开更多
Tunable light-matter interactions are exhibited by organic low-dimensional crystals,making these crystals a promising platform for organic photonics.However,the precise synthesis of organic low-dimensional crystals re...Tunable light-matter interactions are exhibited by organic low-dimensional crystals,making these crystals a promising platform for organic photonics.However,the precise synthesis of organic low-dimensional crystals remains challenging due to the stochastic nature of molecular nucleation processes.Herein,the directed nucleation process is driven by the introduction of metastable seed-crystals as the trunk,which ultimately leads to branched-array organic heterostructures.The successful formation of organic heterostructures with high-density branched arrays is attributed to the highest attachment energy(E_(att)(023)=-104.25 kcal mol^(-1))of the exposed(023)crystal plane during the seed-crystal growth route.Significantly,these as-prepared heterostructures inherently have an ultralow lattice mismatch ratioηof 0.7%between trunk and branch,which contributes to the multi-channel photon transportation.Therefore,this work provides valuable insights into a versatile synthetic strategy for accessing low-dimensional heterostructures for integrated optoelectronics.展开更多
The main drawbacks of vanadium oxide as a cathode material are its low conductivity, low practical capacity and poor cycling stability. Adding Cr can improve its conductivity and a metastable amorphous state may provi...The main drawbacks of vanadium oxide as a cathode material are its low conductivity, low practical capacity and poor cycling stability. Adding Cr can improve its conductivity and a metastable amorphous state may provide higher capacity and stability. In this work, metastable amorphous Cr-V-O nano- particles have been successfully prepared through a facile co-precipitation reaction followed by annealing treatment. As a cathode material for lithium batteries, the metastable amorphous Cr-V-O nanoparticles exhibit high capacity （260 mAh/g at 100 mA/g between 1.5-4 V）, low capacity loss （more than 80% was retained after 200 cycles at 100 mA/g） and high rate capability （up to 3 A/g）.展开更多
基金financially supported by the National Natural Science Foundation of China(52102233)Science and Technology Project of Hebei Education Department(QN2023019).
文摘In recent years,aqueous aluminum ion batteries have been widely studied owing to their abundant energy storage and high theo retical capacity.An in-depth study of vanadium oxide materials is necessary to address the precipitation of insoluble products covered cathode surface and the slow reaction kinetics.Therefore,a method using a simple one-step hydrothermal preparation and oxalic acid to regulate oxygen vacancies has been reported.A high starting capacity(400 mAh g^(-1))can be achieved by Ov-V2O5,and it is capable of undergoing 200 cycles at 0.4 A g^(-1),with a termination discharge capacity of103 mAh g^(-1).Mechanism analysis demonstrated that metastable structures(AlxV2O5and HxV2O5)were constructed through the insertion of Al^(3+)/H^(+)during discharging,which existed in the lattice intercalation with V2O5.The incorporation of oxygen vacancies lowers the reaction energy barrier while improving the ion transport efficiency.In addition,the metastable structure allows the electrostatic interaction between Al3+and the main backbone to establish protection and optimize the transport channel.In parallel,this work exploits ex-situ characterization and DFT to obtain a profound insight into the instrumental effect of oxygen vacancies in the construction of metastable structures during in-situ electrochemical activation,with a view to better understanding the mechanism of the synergistic participation of Al3+and H+in the reaction.This work not only reports a method for cathode materials to modulate oxygen vacancies,but also lays the foundation for a deeper understanding of the metastable structure of vanadium oxides.
基金Supported by the National Key Research and Development Program of China under Grant Nos 2016YFA0301003 and 2016YFA0300403the National Natural Science Foundation of China under Grant Nos 11521404,11634009,U1632102,11504230,11674222,11574202,11674226,11574201 and U1632272
文摘Surface structures and properties of Sn islands grown on superconducting substrate 2H-NbSe2（0001）are studied using low temperature scanning tunneling microscopy or spectroscopy.The pure face-centered cubic（fee）structure of Sn surface is obtained.Superconductivity is also detected on the fcc-Sn（111）surface,and the size of superconducting gap on the Sn surface is nearly the same as that on the superconducting substrate.Furthermore,phase transition occurs from fcc-Sn（111）toβ-Sn（001）by keeping the sample at room temperature for a certain time.Due to the strain relaxation on theβ-Sn islands,both the in-plane unit cell and out-of-plane structures distort,and the height of surface atoms varies periodically to form a universal ripple structure.
基金financial support from the Natural Science Foundation of Jiangsu Province (BK20230010)the National Natural Science Foundation of China (52173177,52473314,22475122)+2 种基金the Natural Science Foundation of Shandong Province (ZR2020MB054)the Training Program for Excellent Young Innovators of Changsha (kq2206026)the Collaborative Innovation Center of Suzhou Nano Science&Technology。
文摘Tunable light-matter interactions are exhibited by organic low-dimensional crystals,making these crystals a promising platform for organic photonics.However,the precise synthesis of organic low-dimensional crystals remains challenging due to the stochastic nature of molecular nucleation processes.Herein,the directed nucleation process is driven by the introduction of metastable seed-crystals as the trunk,which ultimately leads to branched-array organic heterostructures.The successful formation of organic heterostructures with high-density branched arrays is attributed to the highest attachment energy(E_(att)(023)=-104.25 kcal mol^(-1))of the exposed(023)crystal plane during the seed-crystal growth route.Significantly,these as-prepared heterostructures inherently have an ultralow lattice mismatch ratioηof 0.7%between trunk and branch,which contributes to the multi-channel photon transportation.Therefore,this work provides valuable insights into a versatile synthetic strategy for accessing low-dimensional heterostructures for integrated optoelectronics.
文摘The main drawbacks of vanadium oxide as a cathode material are its low conductivity, low practical capacity and poor cycling stability. Adding Cr can improve its conductivity and a metastable amorphous state may provide higher capacity and stability. In this work, metastable amorphous Cr-V-O nano- particles have been successfully prepared through a facile co-precipitation reaction followed by annealing treatment. As a cathode material for lithium batteries, the metastable amorphous Cr-V-O nanoparticles exhibit high capacity （260 mAh/g at 100 mA/g between 1.5-4 V）, low capacity loss （more than 80% was retained after 200 cycles at 100 mA/g） and high rate capability （up to 3 A/g）.
