Lithium ion batteries（LIBs） are currently best energy storage devices providing rechargeable electrical storage to wide variety of applications – from portable electronics to automobiles. Though, these batteries ar...Lithium ion batteries（LIBs） are currently best energy storage devices providing rechargeable electrical storage to wide variety of applications – from portable electronics to automobiles. Though, these batteries are fully adopted, widely used and commercialized, but researchers are still extensively working on their constituent materials and developing technology to improve their performance. A major part of related research activities is devoted to the electrode of the battery for improvement in its performance thereby addressing issues like safety, lifetime, specific capacity, energy density and most importantly abundance and cost. There are number of cathode materials that have been proposed and tested at laboratory scale and subsequently utilized in commercialized batteries ever since the appearance of LIBs. Owing to the availability of improved computational resources in the last decade, first principles calculation has become a reliable tool and played a vital role to predict the material properties of electrodes prior to their experimental analysis. This review gives a comprehensive insight and thorough analysis of the global research efforts related to the cathode materials based on first principles framework, sheds light on current status of knowledge and explores the ways forward.展开更多
We study the electronic properties of CuAlO2 doped with S by the first principles calculations and find that the band gap of CuAlO2 is reduced after the doping.At the same time,the effective masses are also reduced an...We study the electronic properties of CuAlO2 doped with S by the first principles calculations and find that the band gap of CuAlO2 is reduced after the doping.At the same time,the effective masses are also reduced and the density of states could cross the Fermi level.These results show that the conductivity of CuAlO2 could be enhanced by doping the impurities of S,which needs to be further studied.展开更多
The profound impact of excited magnetic states on the intricate interplay between electron and lattice behaviors in magnetic materials is a topic of great interest.Unfortunately,despite the significant strides that ha...The profound impact of excited magnetic states on the intricate interplay between electron and lattice behaviors in magnetic materials is a topic of great interest.Unfortunately,despite the significant strides that have been made in first-principles methods,accurately tracking these phenomena remains a challenging and elusive task.The crux of the challenge that lies before us is centered on the intricate task of characterizing the magnetic configuration of an excited state,utilizing a first-principle approach that is firmly rooted in the ground state of the system.We propose a versatile self-adaptive spin-constrained density functional theory formalism.By iteratively optimizing the constraining field alongside the electron wave function during energy minimization,we are able to obtain an accurate potential energy surface that captures the longitudinal and transverse variations of magnetization in itinerant ferromagnetic Fe.Moreover,this technique allows us to identify the subtle coupling between magnetic moments and other degrees of freedom by tracking energy variation,providing new insights into the intricate interplay between magnetic interactions,electronic band structure,and phonon dispersion curves in single-layered CrI_(3).This new methodology represents a significant breakthrough in our ability to probe the complex and multifaceted properties of magnetic systems.展开更多
Microalloying is an effective approach to improve the mechanical properties of γ-TiAl intermetallic compound.Knowledge about the site occupancy of the ternary alloying element in the crystal lattice ofγ-TiAl is high...Microalloying is an effective approach to improve the mechanical properties of γ-TiAl intermetallic compound.Knowledge about the site occupancy of the ternary alloying element in the crystal lattice ofγ-TiAl is highly demanded in order to understand the physics underlying the alloying effect.Previous first-principle methods-based thermodynamic models for the determination of the site occupancy were based on the point defect gas approximation with the interaction between the point defects neglected.In the present work,we include the point defect interaction energy in the thermodynamic model,which allows us to predict the site occupancy of the ternary alloying element inγ-TiAl beyond the point defect gas approximation.The model is applied to theγ-TiAl-Nb alloy.We show that,at low temperature,the site occupancy of Nb atoms depends on the composition of the alloy:Nb atoms occupy the A1 sublattice for the Ti-rich alloy but occupy Ti sublattice for the Al-rich alloy.The fraction of Nb atoms occupying A1 sublattice in the Ti-rich alloy decreases drastically,whereas the fraction of Nb atoms on the Ti sublattice in the Al-rich alloy decreases slightly with increasing temperature.At high temperature,Nb atoms occupy dominantly the Ti sublattice for both the Ti-rich and Al-rich alloys.The interaction between the point defects makes the Ti sublattice more favorable for the Nb atoms to occupy.展开更多
基金Higprovide financial support vide 6509/Punjab/NRPU/R&D/HEC/2016
文摘Lithium ion batteries（LIBs） are currently best energy storage devices providing rechargeable electrical storage to wide variety of applications – from portable electronics to automobiles. Though, these batteries are fully adopted, widely used and commercialized, but researchers are still extensively working on their constituent materials and developing technology to improve their performance. A major part of related research activities is devoted to the electrode of the battery for improvement in its performance thereby addressing issues like safety, lifetime, specific capacity, energy density and most importantly abundance and cost. There are number of cathode materials that have been proposed and tested at laboratory scale and subsequently utilized in commercialized batteries ever since the appearance of LIBs. Owing to the availability of improved computational resources in the last decade, first principles calculation has become a reliable tool and played a vital role to predict the material properties of electrodes prior to their experimental analysis. This review gives a comprehensive insight and thorough analysis of the global research efforts related to the cathode materials based on first principles framework, sheds light on current status of knowledge and explores the ways forward.
基金supported by the National Laboratory of Solid State Microstructures (Grant No. 2010YJ07)
文摘We study the electronic properties of CuAlO2 doped with S by the first principles calculations and find that the band gap of CuAlO2 is reduced after the doping.At the same time,the effective masses are also reduced and the density of states could cross the Fermi level.These results show that the conductivity of CuAlO2 could be enhanced by doping the impurities of S,which needs to be further studied.
基金funding provided by Shanghai Jiao Tong Universityfunded by the National Natural Science Foundation of China(Grant Nos.U2330401 and 51790494).
文摘The profound impact of excited magnetic states on the intricate interplay between electron and lattice behaviors in magnetic materials is a topic of great interest.Unfortunately,despite the significant strides that have been made in first-principles methods,accurately tracking these phenomena remains a challenging and elusive task.The crux of the challenge that lies before us is centered on the intricate task of characterizing the magnetic configuration of an excited state,utilizing a first-principle approach that is firmly rooted in the ground state of the system.We propose a versatile self-adaptive spin-constrained density functional theory formalism.By iteratively optimizing the constraining field alongside the electron wave function during energy minimization,we are able to obtain an accurate potential energy surface that captures the longitudinal and transverse variations of magnetization in itinerant ferromagnetic Fe.Moreover,this technique allows us to identify the subtle coupling between magnetic moments and other degrees of freedom by tracking energy variation,providing new insights into the intricate interplay between magnetic interactions,electronic band structure,and phonon dispersion curves in single-layered CrI_(3).This new methodology represents a significant breakthrough in our ability to probe the complex and multifaceted properties of magnetic systems.
基金financial supports from the National Key Research and Development Program of China under Grant No.2016YFB0701301the National Natural Science Foundation of China under Grant No.91860107
文摘Microalloying is an effective approach to improve the mechanical properties of γ-TiAl intermetallic compound.Knowledge about the site occupancy of the ternary alloying element in the crystal lattice ofγ-TiAl is highly demanded in order to understand the physics underlying the alloying effect.Previous first-principle methods-based thermodynamic models for the determination of the site occupancy were based on the point defect gas approximation with the interaction between the point defects neglected.In the present work,we include the point defect interaction energy in the thermodynamic model,which allows us to predict the site occupancy of the ternary alloying element inγ-TiAl beyond the point defect gas approximation.The model is applied to theγ-TiAl-Nb alloy.We show that,at low temperature,the site occupancy of Nb atoms depends on the composition of the alloy:Nb atoms occupy the A1 sublattice for the Ti-rich alloy but occupy Ti sublattice for the Al-rich alloy.The fraction of Nb atoms occupying A1 sublattice in the Ti-rich alloy decreases drastically,whereas the fraction of Nb atoms on the Ti sublattice in the Al-rich alloy decreases slightly with increasing temperature.At high temperature,Nb atoms occupy dominantly the Ti sublattice for both the Ti-rich and Al-rich alloys.The interaction between the point defects makes the Ti sublattice more favorable for the Nb atoms to occupy.
