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Thermodynamic dataset of electrode materials in lithium ion … · (1) Ab initio and empirical...
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Keke Chang , Bengt Hallstedt, Denis Music Thermodynamic dataset of electrode materials in lithium ion batteries GTT Workshop 2016, Herzogenrath RWTH Aachen University Julian Fischer, Carlos Ziebert, Sven Ulrich, Hans J. Seifert Karlsruhe Institute of Technology (KIT) [email protected]
Transcript of Thermodynamic dataset of electrode materials in lithium ion … · (1) Ab initio and empirical...
Keke Chang, Bengt Hallstedt, Denis Music
Thermodynamic dataset of electrode materials in lithium ion batteries
GTT Workshop 2016, Herzogenrath
RWTH Aachen University
Julian Fischer, Carlos Ziebert, Sven Ulrich, Hans J. Seifert
Karlsruhe Institute of Technology (KIT)
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Outline
Background
Ab initio and empirical method
CALPHAD and thermodynamic description• The LiNiO –NiO system
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Li ion batteries
Keke Chang
• The LiNiO2–NiO2 system
• The LiCoO2–CoO2 system
• The Li(Co,Ni)O2–(Co,Ni)O2 system
Cell voltages of Li ion cells
Summary and outlook
Background
O3-LiCoO2- High price- Safety problem
O3-LiNiO2- Difficult to synthesize
• Phase changes in cycling of Li/O3-LiCoO2:O3, O3’ (ordered), M, H1-3 and O1
Most stable
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Keke Chang
Crystal structures of LiCoO2 with different stacking of Li layers.
O3-Li(Co, Ni)O2- Co and Ni have unlimited solid solubility;
- Can be deintercalated to O3-Li0.4(Co, Ni)O2;
- Can remain as the layered O3 structure.
Most stable
Gibbs energy function:
(1)
Ab initio and empirical method
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Keke Chang
The flow chart of the present theoretical approaches.
Cell voltage of a Li/Li+ cell:
(2)
[Ref] K. Chang, B. Hallstedt, D. Music, Chem. Mater. 24 (2012) 97-105.
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Evaluation of thermodynamic and electrochemical properties using ab initio and empirical methods(Simple models for the phases)
Li/O3-LiCoO2 Li/O2-LiCoO2 Li/O3-LiNiO2
CALPHAD method(More appropriate models)
a b c
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Ab initio and empirical method
Keke Chang
Calculated cell voltages at 300 K compared to the experimental data, CALPHAD calculation and the previous theoretical results.
[Ref] K. Chang, B. Hallstedt, D. Music, Chem. Mater. 24 (2012) 97-105.
Background
O3-LiCoO2- High price- Safety problem
O3-LiNiO2- Difficult to synthesize
• Phase changes in cycling of Li/O3-LiCoO2:O3, O3’ (ordered), M, H1-3 and O1
Most stable
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Keke Chang
Crystal structures of LiCoO2 with different stacking of Li layers.
O3-Li(Co, Ni)O2- Co and Ni have unlimited solid solubility;
- Can be deintercalated to O3-Li0.4(Co, Ni)O2;
- Can remain as the layered O3 structure.
Most stable
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Outline
Background
Ab initio and empirical method
CALPHAD and thermodynamic description• The LiNiO –NiO system
07.07.2016
Li ion batteries
Keke Chang
• The LiNiO2–NiO2 system
• The LiCoO2–CoO2 system
• The Li(Co,Ni)O2–(Co,Ni)O2 system
Cell voltages of Li ion cells
Summary and outlook
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(1) Ordered and disordered phases
(2) End-member compound (Cp well-defined)
CALPHADCALculation of PHAse Diagrams
Models for individual phases:
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Keke Chang
(2) End-member compound (Cp well-defined)
(3) End-member compound (Neumann-Kopp rule)
[Ref 1] http://www.sgte.org/[Ref 2] M. Hillert, J. Alloys Compd. 320 (2001) 161-176.[Ref 3] I. Ansara, N. Dupin, H.L. Lukas, B. Sundman, J. Alloys Compd. 247 (1997) 20-30.
Thermodynamic descriptionI. LiNiO2–NiO2 system
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Keke Chang
Calculated thermodynamic properties compared with the literature data: (a) Heat capacity of O3-LiNiO2; (b) Enthalpies of formation for O3-LixNiO2 (0 < x < 1) relative to O3-NiO2 and O3-LiNiO2.
[Ref] K. Chang, B. Hallstedt, D. Music, CALPHAD 37 (2012) 100-107.
Thermodynamic descriptionI. LiNiO2–NiO2 system
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Keke Chang
Calculated phase diagram of the LiNiO2–NiO2 pseudo-binary system compared with the experimental data: (a) from 300 K to 450 K; (b) at 298 K.
[Ref] K. Chang, B. Hallstedt, D. Music, CALPHAD 37 (2012) 100-107.
a b
Thermodynamic descriptionII. LiCoO2–CoO2 system
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Keke Chang
Fig. (a) Heat capacity data of O3-LiCoO2 from literature compared with the Cp function used in this work. The result from the Neumann-Kopp rule [Ref] is also presented. (b) Calculated enthalpies of formation for O3-, O3’-, and H1-3 relative to O3-LiCoO2 and O3-CoO2 compared with literature data.
[Ref] K. Chang, B. Hallstedt, D. Music, J. Fischer, C. Ziebert, S. Ulrich, H.J. Seifert, CALPHAD 41 (2013) 6
Thermodynamic descriptionIII. The O3 structural Li(Co,Ni)O2–(Co,Ni)O2 system
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Fig. Experimental and calculated enthalpies of formation for LiCoyNi1-yO2.
Fig. Cell parameters and c/a ratio vs. y in LiCoyNi1-yO2 .
� The LiCoO2–CoO2 and LiNiO2–NiO2 systems are considered to be ideally mixing.
[Ref] K. Chang, B. Hallstedt, D. Music, CALPHAD 37 (2012) 100-107.
Cell voltages of Li ion cells
Li/O3-LixNiO2 (T=300 K)Li/O3-LixCoO2 (T=300 K) ba
Cell voltage of a Li/Li+ cell:
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Li/O3-LixNiO2 (T=300 K)Li/O3-LixCoO2 (T=300 K) b
Summary
� Thermodynamic dataset obtained.
� Experimental and ab initio data well reproduced.
� Cell voltage predicted.
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� Amorphous anode
� Thin film electrode for LIB
� Thermodynamic dataset of Si-based systems
Outlook
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Acknowledgement:
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Keke Chang
Thank you for your attention!
