Alloyed based anode materials with high theoretical specific capacity and low reaction potential are considered to be highly potential high-energy density anode materials for alkali metal ion batteries(AMIBs).Thus,the...Alloyed based anode materials with high theoretical specific capacity and low reaction potential are considered to be highly potential high-energy density anode materials for alkali metal ion batteries(AMIBs).Thus,the design of alloyed based materials with high electrochemical performance has attracted great attention.Among the numerous characterization methods for guiding electrode materials design,in situ transmission electron microscopy(TEM)gradually plays an irreplaceable role due to its high temporal and spatial resolution in directly observing the change of morphology,crystal structure and element evolutions.Herein,we reviewed the two current research hotspots and mainly focused on the structure design of alloyed based electrode material under the guidance of in situ TEM.Specifically,various nanostructure designs of alloyed based electrode materials with guidance of in situ TEM were employed to solve the key scientific issues of the violent volume change during alloying/dealloying processes for enhanced electrochemical performances.Mainly through introducing buffer space in the electrode material to reduce volume change to improve structural stability,including porous structure(0 D),nanotube structure(1 D),simple hollow structure,yolk-shell structure and some hybrid hollow structures(3 D).Furthermore,the direct guidance of in situ TEM is expected for creating new opportunities to nextgeneration electrode material design for AMIBs.展开更多
The hazard of Hg ion pollution triggers the motivation to explore a fast, sensitive, and reliable detection method. Here, we design and fabricate novel 36-nm-thick Ag-Au composite layers alternately deposited on three...The hazard of Hg ion pollution triggers the motivation to explore a fast, sensitive, and reliable detection method. Here, we design and fabricate novel 36-nm-thick Ag-Au composite layers alternately deposited on three-dimensional (3D) periodic SiO2 nanogrids as surface-enhanced Raman scattering (SERS) probes. The SERS effects of the probes depend mainly on the positions and intensities of their localized surface plasmon resonance (LSPR) peaks, which is confirmed by the absorption spectra from finite-difference time-domain (FDTD) calculations. By optimizing the structure and material to maximize the intrinsic electric field enhancement based on the design method of 3D periodic SERS probes proposed, high performance of the Ag-Au/SiO2 nanogrid probes is achieved with the stability further enhanced by annealing. The optimized probes show the outstanding stability with only 4.0% SERS intensity change during 10-day storage, the excellent detection uniformity of 5.78% (RSD), the detection limit of 5.0 × 10-12 M (1 ppt), and superior selectivity for Hg ions. The present study renders it possible to realize the rapid and reliable detection of trace heavy metal ions by developing high- performance 3D periodic structure SERS probes by designing novel 3D structure and optimizing plasmonic material.展开更多
A barcode-like waveguide nanostructure with discretized multilevel pixel lines is designed and optimized by a nonlinear search algorithm. We obtain the design of a one-dimensional multilevel nanostructure with-1.04 d ...A barcode-like waveguide nanostructure with discretized multilevel pixel lines is designed and optimized by a nonlinear search algorithm. We obtain the design of a one-dimensional multilevel nanostructure with-1.04 d B efficiency for surface normal coupling to a standard single-mode fiber. Another design is achieved from the automatic optimization process, which enables polarization-independent coupling to a single-mode fiber. The optimum coupling efficiency is simulated to be-2.83 dB for TE and-3.49 for TM polarization centered near the 1550 nm wavelength. Polarization-dependent loss of less than 1 dB over 45.3 nm is achieved.展开更多
基金supported by the National Natural Science Foundation of China(No.51621001)the National Key Research and Development Program of China(No.2016YFA0202604)Key Laboratory of Resource Chemistry,Ministry of Education Joint International Research Laboratory of Resource Chemistry and the open fund from Hunan Provincial Key Laboratory of Advanced Materials for New Energy Storage and Conversion(No.2018TP1037-202005)。
文摘Alloyed based anode materials with high theoretical specific capacity and low reaction potential are considered to be highly potential high-energy density anode materials for alkali metal ion batteries(AMIBs).Thus,the design of alloyed based materials with high electrochemical performance has attracted great attention.Among the numerous characterization methods for guiding electrode materials design,in situ transmission electron microscopy(TEM)gradually plays an irreplaceable role due to its high temporal and spatial resolution in directly observing the change of morphology,crystal structure and element evolutions.Herein,we reviewed the two current research hotspots and mainly focused on the structure design of alloyed based electrode material under the guidance of in situ TEM.Specifically,various nanostructure designs of alloyed based electrode materials with guidance of in situ TEM were employed to solve the key scientific issues of the violent volume change during alloying/dealloying processes for enhanced electrochemical performances.Mainly through introducing buffer space in the electrode material to reduce volume change to improve structural stability,including porous structure(0 D),nanotube structure(1 D),simple hollow structure,yolk-shell structure and some hybrid hollow structures(3 D).Furthermore,the direct guidance of in situ TEM is expected for creating new opportunities to nextgeneration electrode material design for AMIBs.
基金Project supported by the National Key Research and Development Program of China(Grant No.2017YFA0207104)the Strategic Priority Research Program of the Chinese Academy of Sciences(Grant No.XDA09040101)+2 种基金the National Natural Science Foundation of China(Grant No.Y6061111JJ)the Youth Innovation Promotion Association of Chinese Academy of Sciences(Grant No.2015030)the Key Technology Talent Program of Chinese Academy of Sciences(Grant Nos.Y8482911ZX and Y7602921ZX)
文摘The hazard of Hg ion pollution triggers the motivation to explore a fast, sensitive, and reliable detection method. Here, we design and fabricate novel 36-nm-thick Ag-Au composite layers alternately deposited on three-dimensional (3D) periodic SiO2 nanogrids as surface-enhanced Raman scattering (SERS) probes. The SERS effects of the probes depend mainly on the positions and intensities of their localized surface plasmon resonance (LSPR) peaks, which is confirmed by the absorption spectra from finite-difference time-domain (FDTD) calculations. By optimizing the structure and material to maximize the intrinsic electric field enhancement based on the design method of 3D periodic SERS probes proposed, high performance of the Ag-Au/SiO2 nanogrid probes is achieved with the stability further enhanced by annealing. The optimized probes show the outstanding stability with only 4.0% SERS intensity change during 10-day storage, the excellent detection uniformity of 5.78% (RSD), the detection limit of 5.0 × 10-12 M (1 ppt), and superior selectivity for Hg ions. The present study renders it possible to realize the rapid and reliable detection of trace heavy metal ions by developing high- performance 3D periodic structure SERS probes by designing novel 3D structure and optimizing plasmonic material.
基金National Natural Science Foundation of China(NSFC)(61505039)Shenzhen Municipal Science and Technology Plan Project(JCYJ20150403161923530)
文摘A barcode-like waveguide nanostructure with discretized multilevel pixel lines is designed and optimized by a nonlinear search algorithm. We obtain the design of a one-dimensional multilevel nanostructure with-1.04 d B efficiency for surface normal coupling to a standard single-mode fiber. Another design is achieved from the automatic optimization process, which enables polarization-independent coupling to a single-mode fiber. The optimum coupling efficiency is simulated to be-2.83 dB for TE and-3.49 for TM polarization centered near the 1550 nm wavelength. Polarization-dependent loss of less than 1 dB over 45.3 nm is achieved.