High-capacity metal chalcogenides often suffer from low initial coulombic efficiency(ICE)and serious capacity fading owing to the shuttle effect and volumetric expansion.Various carbon-coating and fixing methods were ...High-capacity metal chalcogenides often suffer from low initial coulombic efficiency(ICE)and serious capacity fading owing to the shuttle effect and volumetric expansion.Various carbon-coating and fixing methods were used to improve the above-mentioned performance.However,the synthesis processes of them are complex and time-consuming,limiting their engineering applications.Herein,polar polymer binder sodium polyacrylate(PAANa)is selected as an example to solve the problems of metal chalcogenides(bare micro-sized FeS)without any modification of the active materials.The special function of the polymer binder in the interface between the active material particles and the electrolytes demonstrates that a PAANa-induced network structure on the surface of ion sulfide microparticles not only buffers the mechanical stress of particles during discharging-charging,but also participates in forming a ductile solid electrolyte interphase(SEI)with high interfacial ion transportation and enhanced ICE.The cyclic stability and rate performance can be simultaneously improved.This work not only provides a new understanding of the binder on electrode,but also introduces a new way to improve the performance of batteries.展开更多
The main aim of this work is to study numerically the influence of an external magnetic field on the solidification processes of two-component materials. Based on the continuum model of two-phase flow a mathematical m...The main aim of this work is to study numerically the influence of an external magnetic field on the solidification processes of two-component materials. Based on the continuum model of two-phase flow a mathematical model for the directional solidification of a binary alloy in a magnetic field is presented. The model includes mass, momentum, energy and species mass conservation equations written in compressible form and additional relationships describing the temperature-solute coupling. The geometry under study is a cylindrical mold with adiabatic walls and cooled bottom. The macroscale transport in the solidification of alloys is governed by the progress of the two-phase mushy zone, which is treated by means of a porous medium approach. The volume fraction of liquid and solid phases, respectively, is calculated from a 2D approximation of the phase diagram. The results of calculation are compared with experimental data.展开更多
基金supported by the National Natural Science Foundation of China(U1804129,21771164,21671205 and U1804126)Zhongyuan Youth Talent Support Program of Henan ProvinceZhengzhou University Youth Innovation Program。
文摘High-capacity metal chalcogenides often suffer from low initial coulombic efficiency(ICE)and serious capacity fading owing to the shuttle effect and volumetric expansion.Various carbon-coating and fixing methods were used to improve the above-mentioned performance.However,the synthesis processes of them are complex and time-consuming,limiting their engineering applications.Herein,polar polymer binder sodium polyacrylate(PAANa)is selected as an example to solve the problems of metal chalcogenides(bare micro-sized FeS)without any modification of the active materials.The special function of the polymer binder in the interface between the active material particles and the electrolytes demonstrates that a PAANa-induced network structure on the surface of ion sulfide microparticles not only buffers the mechanical stress of particles during discharging-charging,but also participates in forming a ductile solid electrolyte interphase(SEI)with high interfacial ion transportation and enhanced ICE.The cyclic stability and rate performance can be simultaneously improved.This work not only provides a new understanding of the binder on electrode,but also introduces a new way to improve the performance of batteries.
文摘The main aim of this work is to study numerically the influence of an external magnetic field on the solidification processes of two-component materials. Based on the continuum model of two-phase flow a mathematical model for the directional solidification of a binary alloy in a magnetic field is presented. The model includes mass, momentum, energy and species mass conservation equations written in compressible form and additional relationships describing the temperature-solute coupling. The geometry under study is a cylindrical mold with adiabatic walls and cooled bottom. The macroscale transport in the solidification of alloys is governed by the progress of the two-phase mushy zone, which is treated by means of a porous medium approach. The volume fraction of liquid and solid phases, respectively, is calculated from a 2D approximation of the phase diagram. The results of calculation are compared with experimental data.
