Herein,a thermodynamic model aimed at describing deoxidation equilibria in liquid steel was developed.The model provides explicit forms of the activity coefficient of solutes in liquid steel,eliminating the need for t...Herein,a thermodynamic model aimed at describing deoxidation equilibria in liquid steel was developed.The model provides explicit forms of the activity coefficient of solutes in liquid steel,eliminating the need for the minimization of internal Gibbs energy preliminarily when solving deoxidation equilibria.The elimination of internal Gibbs energy minimization is particularly advantageous during the coupling of deoxidation equilibrium calculations with computationally intensive approaches,such as computational fluid dynamics.The model enables efficient calculations through direct embedment of the explicit forms of activity coefficient in the computing code.The proposed thermodynamic model was developed using a quasichemical approach with two key approximations:random mixing of metallic elements(Fe and oxidizing metal) and strong nonrandom pairing of metal and oxygen as nearest neighbors.Through these approximations,the quasichemical approach yielded the activity coefficients of solutes as explicit functions of composition and temperature without requiring the minimization of internal Gibbs energy or the coupling of separate programs.The model was successfully applied in the calculation of deoxidation equilibria of various elements(Al,B,C,Ca,Ce,Cr,La,Mg,Mn,Nb,Si,Ti,V,and Zr).The limitations of the model arising from these assumptions were also discussed.展开更多
Enhancing the energy density of all‐solid‐state batteries(ASSBs)with lithium metal anodes is crucial,but lithium dendrite‐induced short circuits limit fast‐charging capability.This study presents a high‐power ASS...Enhancing the energy density of all‐solid‐state batteries(ASSBs)with lithium metal anodes is crucial,but lithium dendrite‐induced short circuits limit fast‐charging capability.This study presents a high‐power ASSB employing a novel,robust solid electrolyte(SE)with exceptionally high stability at the lithium metal/SE interface,achieved via site‐specific Nb doping in the argyrodite structure.Pentavalent Nb incorporation into Wyckoff 48h sites enhances structural stability,as confirmed by neutron diffraction,X‐ray absorption spectroscopy,magic angle spinning nuclear magnetic resonance,and density functional theory calculations.While Nb doping slightly reduces ionic conductivity,it significantly improves interfacial stability,suppressing dendrite formation and enabling a full cell capable of charging in just 6 min(10‐C rate,16 mA cm−2).This study highlights,for the first time,that electrochemical stability,rather than ionic conductivity,is key to achieving high‐power performance,advancing the commercialization of lithium metal‐based ASSBs.展开更多
文摘Herein,a thermodynamic model aimed at describing deoxidation equilibria in liquid steel was developed.The model provides explicit forms of the activity coefficient of solutes in liquid steel,eliminating the need for the minimization of internal Gibbs energy preliminarily when solving deoxidation equilibria.The elimination of internal Gibbs energy minimization is particularly advantageous during the coupling of deoxidation equilibrium calculations with computationally intensive approaches,such as computational fluid dynamics.The model enables efficient calculations through direct embedment of the explicit forms of activity coefficient in the computing code.The proposed thermodynamic model was developed using a quasichemical approach with two key approximations:random mixing of metallic elements(Fe and oxidizing metal) and strong nonrandom pairing of metal and oxygen as nearest neighbors.Through these approximations,the quasichemical approach yielded the activity coefficients of solutes as explicit functions of composition and temperature without requiring the minimization of internal Gibbs energy or the coupling of separate programs.The model was successfully applied in the calculation of deoxidation equilibria of various elements(Al,B,C,Ca,Ce,Cr,La,Mg,Mn,Nb,Si,Ti,V,and Zr).The limitations of the model arising from these assumptions were also discussed.
基金supported by Companhia Brasileira de Metalurgia e Mineração(CBMM)(CW2246174‐220221)the Technology Innovation Program(20010044,20012224)funded by Ministry of Trade,Industry&Energy(MOTIE,Korea)the Nano&Material Technology Development Program through the National Research Foundation of Korea(NRF)funded by the Ministry of Science and ICT(RS‐2024‐00446825).
文摘Enhancing the energy density of all‐solid‐state batteries(ASSBs)with lithium metal anodes is crucial,but lithium dendrite‐induced short circuits limit fast‐charging capability.This study presents a high‐power ASSB employing a novel,robust solid electrolyte(SE)with exceptionally high stability at the lithium metal/SE interface,achieved via site‐specific Nb doping in the argyrodite structure.Pentavalent Nb incorporation into Wyckoff 48h sites enhances structural stability,as confirmed by neutron diffraction,X‐ray absorption spectroscopy,magic angle spinning nuclear magnetic resonance,and density functional theory calculations.While Nb doping slightly reduces ionic conductivity,it significantly improves interfacial stability,suppressing dendrite formation and enabling a full cell capable of charging in just 6 min(10‐C rate,16 mA cm−2).This study highlights,for the first time,that electrochemical stability,rather than ionic conductivity,is key to achieving high‐power performance,advancing the commercialization of lithium metal‐based ASSBs.
