Silicon-based carbon composites are believed as promising anodes in the near future due to their outstanding specific capacity and relatively lower volume effect compared to pure silicon anodes.Herein,a multilayer sph...Silicon-based carbon composites are believed as promising anodes in the near future due to their outstanding specific capacity and relatively lower volume effect compared to pure silicon anodes.Herein,a multilayer spherical core-shell(M-SCS)electrode with a graphite framework prepared with Si@O-MCMB/C nanoparticles is developed,which aims to realize chemically/mechanically stability during the lithiation/delithiation process with high specific capacity.An electrochemical-/mechanical-coupling model for the M-SCS structure is established with various chemical/mechanical boundary conditions.The simulation of finite difference method(FDM)has been conducted based on the proposed coupling model,by which the diffusion-induced stress along both the radial and the circumferential directions is determined.Moreover,factors that influence the diffusion-induced stress of the M-SCS structure have been discussed and analyzed in detail.展开更多
For organnoboron co mpounds,the substituents on boron atoms are very important because they not only impact on the molecular stability but also significantly modulate the electronic structu res and prope rties.In this...For organnoboron co mpounds,the substituents on boron atoms are very important because they not only impact on the molecular stability but also significantly modulate the electronic structu res and prope rties.In this manuscript,we synthesized two new B←N-co ntaining azaacenes with propynyl groups on boron atoms through one-step Grignard reaction.Replacing fluorine atoms by propynyl groups greatly impacts on the electronic energy levels,especially enhancing the HOMO levels,thus leading to the narrowed HOMO-LUMO bandgaps.These B←N-containing azaacenes exhibit the NIR light-absorption(λabs=706 nm for 2 a and 762 nm for 2 b)and fluorescence properties(λem=740 nm for 2 a and802 nm for 2 b),as well as multiple reversible redox behaviors,which are significantly different from the analogs with fluorine atoms.This study thus provides a functional substituent of boron atom,which may lead to new organoboron materials with fascinating properties.展开更多
基金Project supported by the National Natural Science Foundation of China(Grant Nos.12072229 and 11602167).
文摘Silicon-based carbon composites are believed as promising anodes in the near future due to their outstanding specific capacity and relatively lower volume effect compared to pure silicon anodes.Herein,a multilayer spherical core-shell(M-SCS)electrode with a graphite framework prepared with Si@O-MCMB/C nanoparticles is developed,which aims to realize chemically/mechanically stability during the lithiation/delithiation process with high specific capacity.An electrochemical-/mechanical-coupling model for the M-SCS structure is established with various chemical/mechanical boundary conditions.The simulation of finite difference method(FDM)has been conducted based on the proposed coupling model,by which the diffusion-induced stress along both the radial and the circumferential directions is determined.Moreover,factors that influence the diffusion-induced stress of the M-SCS structure have been discussed and analyzed in detail.
基金supported by the National Natural Science Foundation of China(Nos.21822507,21625403,21761132020)National Key Research and Development Program of China(No.2018YFE0100600)founded by MOST,Youth Innovation Promotion Association of Chinese Academy of Sciences(No.2017265)。
文摘For organnoboron co mpounds,the substituents on boron atoms are very important because they not only impact on the molecular stability but also significantly modulate the electronic structu res and prope rties.In this manuscript,we synthesized two new B←N-co ntaining azaacenes with propynyl groups on boron atoms through one-step Grignard reaction.Replacing fluorine atoms by propynyl groups greatly impacts on the electronic energy levels,especially enhancing the HOMO levels,thus leading to the narrowed HOMO-LUMO bandgaps.These B←N-containing azaacenes exhibit the NIR light-absorption(λabs=706 nm for 2 a and 762 nm for 2 b)and fluorescence properties(λem=740 nm for 2 a and802 nm for 2 b),as well as multiple reversible redox behaviors,which are significantly different from the analogs with fluorine atoms.This study thus provides a functional substituent of boron atom,which may lead to new organoboron materials with fascinating properties.
