- Email: [email protected]
[O19] Recent progress of thermodynamic study with Sn based anode materials for Li-ion battery application
350
Y. DU et al. / CALPHAD: Computer Coupling of Phase Diagrams and Thermochemistry 51 (2015) 344–415
derived coulometric titration curves which are essential for the understanding of the operation of electrochemical cells. http://dx.doi.org/10.1016/j.calphad.2015.01.022
[O16] Thermodynamics of the Pd-Mn system and phase stability of L10-based Pd1-xMn1-yFex þ y Erwin Povoden-Karadeniz, Frank Moszner, Stefan Pogatscher, Peter J. Uggowitzer, Ernst Kozeschnik Recently, Fe-Pd-Mn alloys have attracted considerable interest as magnetic shape memory alloys [1] and as biodegradable materials for medical applications [2]. We present the assessed thermodynamics of the Pd-Mn system and investigate the Fe-solubility in L10-ordered PdMn. In the Pd-Mn system, the intermetallic ordered phases PdMn L10, PdMn B2, orthorhombic Pd2Mn and Pd5Mn3, and Pd3Mn D023 have been observed [3]. It is shown that, based on calorimetric enthalpy, heat content and activity measurements of the B2-phase [4,5] and the experimental phase diagram [6], the thermodynamics of all phases of the system are unambiguously defined. Experimental results from SEM and TEM investigations reveal considerable Fesolubility in PdMn, leading to a higher dissolution temperature of the ternary Pd1-xMn1-yFex þ y phase. After coupling of our CALPHAD results with assessed diffusion mobilities, nucleation theory and the SFFK model for the growth of precipitates, the role of intermetallic Pd1xMn1-yFex þ y for transformation mechanisms in martensitic Pdcontaining Fe-Mn alloys is analyzed. References [1] S. Kauffmann-Weiss, S. Hamann, M.E. Gruner, J. Buschbeck, A. Ludwig, L. Schultz, S. Fähler, Adv. Eng. Mater. 14 (2012) 724. [2] M. Schinhammer, A.C. Hänzi, J.F. Löffler, P.J. Uggowitzer, Acta Biomat 6 (2010) 1705. [3] R. Miida, T. Tajima, D.K. Saha, M.Y. Wey, D. Watanabe, K. Ohshima, Mater. Trans. 9 (2004) 2822. [4] S.V. Meschel, P. Nash, X.-Q. Chen, J. Alloys Compd., 492 (2919) 105. [5] R. Krachler, H. Ipser, K. Komarek, Z. Metallkd., 75 (1984) 724. [6] M. Hansen, K. Anderko, “Constitution of Binary Alloys”, Second Edition, McGraw-Hill, New York, 1958.
http://dx.doi.org/10.1016/j.calphad.2015.01.023
[O17] Thermodynamic modeling of Salt Lake Brine System: Parameterization Strategy Dongdong Li, Dewen Zeng, Xia Yin, Haijun Han Salt lake brine is a complex multi component system, which 2includes Li þ , Na þ , K þ , Mg2þ , Ca2þ , Cl-, SO24 , CO3 , NO3 and borate o etc. Thermodynamic models at 25 C have been developed to simulate the isothermal evaporation of brines. Variable temperature models are in great demand, when the real processes of brines are considered. Reliable simulation of brine depends on the predictive ability of the adopted thermodynamic models. When the mathematical framework of a thermodynamic model is selected, model parameters are the unique affecting factor on the predictive ability of the thermodynamic model. In our previous work, model parameters for aqueous solution are derived from the experimental water activities. While, we find the obtained parameters by using that strategy could not give accurate ionic activity coefficients. In this work, different parameterization
strategies for binary aqueous electrolyte are studied. LiCl þH2O and CaCl2 þ H2O binary systems are selected as test cases to discuss the influence of parameterization method on the predictive ability of a thermodynamic model. The parameters for the aqueous phase are regressed from all kind of accurate thermodynamic measurements (water activity, mean ionic activity coefficient, enthalpy and heat capacity) of the aqueous solution as soon as possible. To correlate the solubility products of a solid at different temperatures, the following equation is adopted. InK ðT Þ ¼ p0 þ p1 T þ p2 T 2 þ p3 InT þ p4 T 1 þ p5 T 2
ð1Þ
From the thermodynamic relations, four parameters are determined from heat capacity equation of the dissolution reaction. The other two parameters in Eq. (1) are fitted from solubility products calculated from the activity coefficient equations of components and some reliable solubility data. In the limiting case, only two reliable solubility data are needed to determine the parameters in Eq. (1). Solubilities of a solid at other temperatures can be predicted accurately from the model parameterized with this strategy, and the excellently temperature extrapolation ability of the binary models will be inhered by the corresponding ternary systems. http://dx.doi.org/10.1016/j.calphad.2015.01.024
[O18] Thermodynamic Calculation of the Mg-Cu-Y System Shuai Zhang, Min Jiang, Hongxiao Li, Yuping Ren, Lei Wang, Gaowu Qin In order to study the phase equilibria of the LPSO phase in the Mgrich Mg-Cu-Y system, very recently a systematic experimental work has been done by Jiang et al., where the equilibrium phase composition, phase relationship and phase transformations of the LPSO phase have been studied. Based on their data, together with previous related studies, in this work, a critical thermodynamic assessment of the MgCu-Y system will be done by a CALPHAD approach. The phase equilibria in the Mg-rich Mg-Cu-Y system at 300, 400 and 450 1C have been thermodynamically analyzed based on experimental data. The ternary long-period stacking ordered (LPSO) phase, which has been proved to be stable in the Mg-CuY system with a limited solid solution range by experiments, has been described as a ternary stoichiometric compound. The thermodynamic stability of the LPSO phase has been thus well defined. It forms by a quasi-peritectic reaction L þ α Mg2Mg24 Y5 þ 14H at 490 1C, experiences the other quasi-peritectic reaction L þ α Mg2Mg2 Cu þ14H at 443 1C, and gets equilibrium with the ɑ-Mg, Mg2Cu and Mg24Y5 phases below 443 1C. http://dx.doi.org/10.1016/j.calphad.2015.01.025
[O19] Recent progress of thermodynamic study with Sn based anode materials for Li-ion battery application Dajian Li, Siegfried Fürtauer, Hans Flandorfer, Damian M. Cupid Sn-based materials can be used to increase anode capacities by as much as 200% compared to traditional graphite anodes.
Y DU et al. / CALPHAD: Computer Coupling of Phase Diagrams and Thermochemistry 51 (2015) 344–415
However, intermetallic anodes based on Sn suffer from large volume strains on lithiation which result in pulverization, degradation of particle to particle contacts, and rapid electrode failure. One way to buffer volume changes is to add another element which forms a matrix to stabilize the structure. Another way to minimize volume changes during cycling is to start with binary phases which exhibit large ternary extensions due to additions of lithium. Cu and Sb are candidate elements which can display these properties, respectively and the combination of these two elements can lead to improved properties of Sn based anodes. During lithiation and de-lithiation, both composition changes as well as phase transformations may take place. Therefore, phase diagrams are essential for understanding and designing battery performance. The aim of the current work is to develop a reliable thermodynamic description for the Cu-Li-Sb-Sn system. Extensive literature research on the Cu-Li-Sb-Sn quaternary system and its sub-systems has been performed. Key experiments in the Cu-Sn, Li-Sn, Cu-Sb and CuLi-Sn systems have been done to generate new data or to verify existing literature information. The Cu-Li, Cu-Sb, Cu-Sn, Li-Sn systems were re-assessed using the CALPHAD method. The results of the thermodynamic modeling of the Cu-Sn and Li-Sn systems were already reported at CALPHAD 2013. The current presentation will focus on our work on the Cu-Li and Cu-Sb subsystems. The Cu-Li system shows a simple eutectic. However, a reassessment of this system was necessary because of new thermodynamic data available. Sshaped enthalpies of mixing for the liquid phase and EMF data for fcc(Cu) were modeled to obtain a new thermodynamic description. The enthalpies of mixing of the ternary Cu-Li-Sn liquid extrapolated using the Muggianu formalism are in good agreement with experimental data and no ternary parameters are required. The Cu-Sb binary phase diagram was remodeled with three main improvements: 1) the liquid was described using the associate model, 2) the high-temperature â phase was described using the (Cu,Sb)0.25(Cu,Sb)0.25(Cu,Sb)0.25(Cu,Sb)0.25 four sublattice model to correctly describe its D03 crystal structure and to be compatible with the Cu-Sn system, and 3) the eutectoid reaction was correctly described. Coulometric curves and EMF data were calculated using the new description. http://dx.doi.org/10.1016/j.calphad.2015.01.026
351
such as thermal expansion behaviors of Invar/anti-invar alloys and water/ice. http://dx.doi.org/10.1016/j.calphad.2015.01.027
[O21] Connecting thermodynamic concepts of semiconductor defect chemistry with electrochemistry Jörg Neugebauer, Mira Todorova
Theoretical and modeling concepts in semiconductor defect chemistry and electrochemistry have hugely evolved over the last years and are crucial for their respective fields of application such as optoelectronics and semiconductor devices or corrosion and battery materials. Despite being based on the same fundamental building blocks - charged defects and ions - the underlying theoretical concepts and communities have little overlap. To bridge the gap we have recently proposed a unified approach that is based on a fully grand-canonical description of both ions and electrons and that connects and “translates” the respective concepts [1]. The new approach naturally links ab initio calculations to experimental observables, such as the pH-scale and the electrode potential, which determine and characterise the state of an electrochemical system. Employing this approach provides surprising new insight into apparently “old” problems such as water stability, opens new routes to construct electrochemical phase (Pourbaix) diagrams, and gives a handle to an absolute alignment of electrochemical potentials. The approach provides also a direct route to study the impact of an electrochemical environment on surface and point defect phase diagrams, a topic that is of great interest in areas such as water splitting or battery materials. References [1] M. Todorova, J. Neugebauer, Phys. Rev. Applied 1 (2014) 014001.
http://dx.doi.org/10.1016/j.calphad.2015.01.028
[O20] Entropy Zi-Kui Liu
Entropy is a statistical concept of nature and a key quantity in science, particularly thermodynamics. It is represented by the Boltzmann formula S¼kBlnW with kB and W being the Boltzmann constant and the number of possible microstates corresponding to the macroscopic state of a system, which gives the logarithmic connection between entropy and probability. The fundamental assumption in this formula is that each microstate has the same probability to be observed statistically. A more general formula is written as S¼-kBΣpilnpi, with pi denoting the probability for the microstate i being observed statistically. The significance of this general formula with respect to the Boltzmann formula resides on the dependence of pi on temperature, pressure, electric and magnetic fields, which results in anomalies in a macroscopically homogeneous system when new metastable microstates are introduced. In this presentation, some examples are discussed
[O22] First-principles calculations of point defects in B2 phase Guoxing Huang, Lijun Zeng, Xing Wang, Libin Liu
The point defects in B2 phase has been studied by many authors since from Bradley and Taylor [1] build up the phase diagram of Al-Ni system. The vacancies are the dominant defect when x o0.5 and antisites when x 40.5 in B2 phase in some systems such as Ni-Al, Co-Al and Fe-Al. whereas in others, including Fe-Co, Cu-Zn, Au-Zn and Ag-Mg, the antisites dominate. Johnson and Brown [2] had deduced the equations for the concentrations of vacancies and antistie defects in B2 ordered phase at thermodynamic equilibrium. G ¼ H0 þ
X d
H Fd xd þ
XX T c Inciα 2ð1 C υ Þ α i iα
Y. DU et al. / CALPHAD: Computer Coupling of Phase Diagrams and Thermochemistry 51 (2015) 344–415
derived coulometric titration curves which are essential for the understanding of the operation of electrochemical cells. http://dx.doi.org/10.1016/j.calphad.2015.01.022
[O16] Thermodynamics of the Pd-Mn system and phase stability of L10-based Pd1-xMn1-yFex þ y Erwin Povoden-Karadeniz, Frank Moszner, Stefan Pogatscher, Peter J. Uggowitzer, Ernst Kozeschnik Recently, Fe-Pd-Mn alloys have attracted considerable interest as magnetic shape memory alloys [1] and as biodegradable materials for medical applications [2]. We present the assessed thermodynamics of the Pd-Mn system and investigate the Fe-solubility in L10-ordered PdMn. In the Pd-Mn system, the intermetallic ordered phases PdMn L10, PdMn B2, orthorhombic Pd2Mn and Pd5Mn3, and Pd3Mn D023 have been observed [3]. It is shown that, based on calorimetric enthalpy, heat content and activity measurements of the B2-phase [4,5] and the experimental phase diagram [6], the thermodynamics of all phases of the system are unambiguously defined. Experimental results from SEM and TEM investigations reveal considerable Fesolubility in PdMn, leading to a higher dissolution temperature of the ternary Pd1-xMn1-yFex þ y phase. After coupling of our CALPHAD results with assessed diffusion mobilities, nucleation theory and the SFFK model for the growth of precipitates, the role of intermetallic Pd1xMn1-yFex þ y for transformation mechanisms in martensitic Pdcontaining Fe-Mn alloys is analyzed. References [1] S. Kauffmann-Weiss, S. Hamann, M.E. Gruner, J. Buschbeck, A. Ludwig, L. Schultz, S. Fähler, Adv. Eng. Mater. 14 (2012) 724. [2] M. Schinhammer, A.C. Hänzi, J.F. Löffler, P.J. Uggowitzer, Acta Biomat 6 (2010) 1705. [3] R. Miida, T. Tajima, D.K. Saha, M.Y. Wey, D. Watanabe, K. Ohshima, Mater. Trans. 9 (2004) 2822. [4] S.V. Meschel, P. Nash, X.-Q. Chen, J. Alloys Compd., 492 (2919) 105. [5] R. Krachler, H. Ipser, K. Komarek, Z. Metallkd., 75 (1984) 724. [6] M. Hansen, K. Anderko, “Constitution of Binary Alloys”, Second Edition, McGraw-Hill, New York, 1958.
http://dx.doi.org/10.1016/j.calphad.2015.01.023
[O17] Thermodynamic modeling of Salt Lake Brine System: Parameterization Strategy Dongdong Li, Dewen Zeng, Xia Yin, Haijun Han Salt lake brine is a complex multi component system, which 2includes Li þ , Na þ , K þ , Mg2þ , Ca2þ , Cl-, SO24 , CO3 , NO3 and borate o etc. Thermodynamic models at 25 C have been developed to simulate the isothermal evaporation of brines. Variable temperature models are in great demand, when the real processes of brines are considered. Reliable simulation of brine depends on the predictive ability of the adopted thermodynamic models. When the mathematical framework of a thermodynamic model is selected, model parameters are the unique affecting factor on the predictive ability of the thermodynamic model. In our previous work, model parameters for aqueous solution are derived from the experimental water activities. While, we find the obtained parameters by using that strategy could not give accurate ionic activity coefficients. In this work, different parameterization
strategies for binary aqueous electrolyte are studied. LiCl þH2O and CaCl2 þ H2O binary systems are selected as test cases to discuss the influence of parameterization method on the predictive ability of a thermodynamic model. The parameters for the aqueous phase are regressed from all kind of accurate thermodynamic measurements (water activity, mean ionic activity coefficient, enthalpy and heat capacity) of the aqueous solution as soon as possible. To correlate the solubility products of a solid at different temperatures, the following equation is adopted. InK ðT Þ ¼ p0 þ p1 T þ p2 T 2 þ p3 InT þ p4 T 1 þ p5 T 2
ð1Þ
From the thermodynamic relations, four parameters are determined from heat capacity equation of the dissolution reaction. The other two parameters in Eq. (1) are fitted from solubility products calculated from the activity coefficient equations of components and some reliable solubility data. In the limiting case, only two reliable solubility data are needed to determine the parameters in Eq. (1). Solubilities of a solid at other temperatures can be predicted accurately from the model parameterized with this strategy, and the excellently temperature extrapolation ability of the binary models will be inhered by the corresponding ternary systems. http://dx.doi.org/10.1016/j.calphad.2015.01.024
[O18] Thermodynamic Calculation of the Mg-Cu-Y System Shuai Zhang, Min Jiang, Hongxiao Li, Yuping Ren, Lei Wang, Gaowu Qin In order to study the phase equilibria of the LPSO phase in the Mgrich Mg-Cu-Y system, very recently a systematic experimental work has been done by Jiang et al., where the equilibrium phase composition, phase relationship and phase transformations of the LPSO phase have been studied. Based on their data, together with previous related studies, in this work, a critical thermodynamic assessment of the MgCu-Y system will be done by a CALPHAD approach. The phase equilibria in the Mg-rich Mg-Cu-Y system at 300, 400 and 450 1C have been thermodynamically analyzed based on experimental data. The ternary long-period stacking ordered (LPSO) phase, which has been proved to be stable in the Mg-CuY system with a limited solid solution range by experiments, has been described as a ternary stoichiometric compound. The thermodynamic stability of the LPSO phase has been thus well defined. It forms by a quasi-peritectic reaction L þ α Mg2Mg24 Y5 þ 14H at 490 1C, experiences the other quasi-peritectic reaction L þ α Mg2Mg2 Cu þ14H at 443 1C, and gets equilibrium with the ɑ-Mg, Mg2Cu and Mg24Y5 phases below 443 1C. http://dx.doi.org/10.1016/j.calphad.2015.01.025
[O19] Recent progress of thermodynamic study with Sn based anode materials for Li-ion battery application Dajian Li, Siegfried Fürtauer, Hans Flandorfer, Damian M. Cupid Sn-based materials can be used to increase anode capacities by as much as 200% compared to traditional graphite anodes.
Y DU et al. / CALPHAD: Computer Coupling of Phase Diagrams and Thermochemistry 51 (2015) 344–415
However, intermetallic anodes based on Sn suffer from large volume strains on lithiation which result in pulverization, degradation of particle to particle contacts, and rapid electrode failure. One way to buffer volume changes is to add another element which forms a matrix to stabilize the structure. Another way to minimize volume changes during cycling is to start with binary phases which exhibit large ternary extensions due to additions of lithium. Cu and Sb are candidate elements which can display these properties, respectively and the combination of these two elements can lead to improved properties of Sn based anodes. During lithiation and de-lithiation, both composition changes as well as phase transformations may take place. Therefore, phase diagrams are essential for understanding and designing battery performance. The aim of the current work is to develop a reliable thermodynamic description for the Cu-Li-Sb-Sn system. Extensive literature research on the Cu-Li-Sb-Sn quaternary system and its sub-systems has been performed. Key experiments in the Cu-Sn, Li-Sn, Cu-Sb and CuLi-Sn systems have been done to generate new data or to verify existing literature information. The Cu-Li, Cu-Sb, Cu-Sn, Li-Sn systems were re-assessed using the CALPHAD method. The results of the thermodynamic modeling of the Cu-Sn and Li-Sn systems were already reported at CALPHAD 2013. The current presentation will focus on our work on the Cu-Li and Cu-Sb subsystems. The Cu-Li system shows a simple eutectic. However, a reassessment of this system was necessary because of new thermodynamic data available. Sshaped enthalpies of mixing for the liquid phase and EMF data for fcc(Cu) were modeled to obtain a new thermodynamic description. The enthalpies of mixing of the ternary Cu-Li-Sn liquid extrapolated using the Muggianu formalism are in good agreement with experimental data and no ternary parameters are required. The Cu-Sb binary phase diagram was remodeled with three main improvements: 1) the liquid was described using the associate model, 2) the high-temperature â phase was described using the (Cu,Sb)0.25(Cu,Sb)0.25(Cu,Sb)0.25(Cu,Sb)0.25 four sublattice model to correctly describe its D03 crystal structure and to be compatible with the Cu-Sn system, and 3) the eutectoid reaction was correctly described. Coulometric curves and EMF data were calculated using the new description. http://dx.doi.org/10.1016/j.calphad.2015.01.026
351
such as thermal expansion behaviors of Invar/anti-invar alloys and water/ice. http://dx.doi.org/10.1016/j.calphad.2015.01.027
[O21] Connecting thermodynamic concepts of semiconductor defect chemistry with electrochemistry Jörg Neugebauer, Mira Todorova
Theoretical and modeling concepts in semiconductor defect chemistry and electrochemistry have hugely evolved over the last years and are crucial for their respective fields of application such as optoelectronics and semiconductor devices or corrosion and battery materials. Despite being based on the same fundamental building blocks - charged defects and ions - the underlying theoretical concepts and communities have little overlap. To bridge the gap we have recently proposed a unified approach that is based on a fully grand-canonical description of both ions and electrons and that connects and “translates” the respective concepts [1]. The new approach naturally links ab initio calculations to experimental observables, such as the pH-scale and the electrode potential, which determine and characterise the state of an electrochemical system. Employing this approach provides surprising new insight into apparently “old” problems such as water stability, opens new routes to construct electrochemical phase (Pourbaix) diagrams, and gives a handle to an absolute alignment of electrochemical potentials. The approach provides also a direct route to study the impact of an electrochemical environment on surface and point defect phase diagrams, a topic that is of great interest in areas such as water splitting or battery materials. References [1] M. Todorova, J. Neugebauer, Phys. Rev. Applied 1 (2014) 014001.
http://dx.doi.org/10.1016/j.calphad.2015.01.028
[O20] Entropy Zi-Kui Liu
Entropy is a statistical concept of nature and a key quantity in science, particularly thermodynamics. It is represented by the Boltzmann formula S¼kBlnW with kB and W being the Boltzmann constant and the number of possible microstates corresponding to the macroscopic state of a system, which gives the logarithmic connection between entropy and probability. The fundamental assumption in this formula is that each microstate has the same probability to be observed statistically. A more general formula is written as S¼-kBΣpilnpi, with pi denoting the probability for the microstate i being observed statistically. The significance of this general formula with respect to the Boltzmann formula resides on the dependence of pi on temperature, pressure, electric and magnetic fields, which results in anomalies in a macroscopically homogeneous system when new metastable microstates are introduced. In this presentation, some examples are discussed
[O22] First-principles calculations of point defects in B2 phase Guoxing Huang, Lijun Zeng, Xing Wang, Libin Liu
The point defects in B2 phase has been studied by many authors since from Bradley and Taylor [1] build up the phase diagram of Al-Ni system. The vacancies are the dominant defect when x o0.5 and antisites when x 40.5 in B2 phase in some systems such as Ni-Al, Co-Al and Fe-Al. whereas in others, including Fe-Co, Cu-Zn, Au-Zn and Ag-Mg, the antisites dominate. Johnson and Brown [2] had deduced the equations for the concentrations of vacancies and antistie defects in B2 ordered phase at thermodynamic equilibrium. G ¼ H0 þ
X d
H Fd xd þ
XX T c Inciα 2ð1 C υ Þ α i iα