Thermodynamics of Lithium Battery Materials

Transcription

1 Thermodynamics of Lithium Battery Materials Hans J. Seifert Elke Schuster, Maren Lepple, Damian Cupid, Peter Franke, Carlos Ziebert Karlsruhe Institute of Technology (KIT) Institute for Applied Materials Applied Materials Physics (IAM-AWP) KIT University of the State of Baden-Wuerttemberg and National Research Center of the Helmholtz Association Gunnar Eriksson Symposium

2 Thermodynamics of Lithium Battery Materials - Introduction - Why battery thermodynamics and phase diagrams? Calculation of voltages, - Calorimetry of lithium ion batteries Isothermal and adiabatic calorimetry - Li Mn O and Li Fe P O materials systems Gunnar Eriksson Symposium 2012

3 Electric vehicles - some examples Mini E (L.A., NY, Berlin; BMW / Vattenfall) Operating range 250 km Smart electric drive (London, Berlin; Daimler / RWE) Operating range 135 km

4 Electric vehicles - some examples i MiEV, Mitsubishi Capacity of Battery: 16 kwh (200kg) 150 km operating range Per single cell: Energy density 218 Wh/l and Specific energy 109 Wh/kg; Specific power 550 W/kg Total of 176 Cells in Battery System

5 Energy stored in 100 kg of best commercial batteries good enough for just 100 km operating range Batteries for Electric Vehicles have to be optimized to high energy density (kwh), save thermal behavior and cycle life Energy density (Wh/l) and specific energy (Wh/kg) determine for a given operating range the volume and mass of battery

6 Battery technology spider chart (USABC) for electrical vehicles (EV) Operating temperature: -40 to +50 C Specific Power Discharge: 300 W/kg Specific Energy at C/3: 150 Wh/kg Selling price at 10k/Jahr: 150$/kWh Power density: 460 W/l Calendar life: 10 years Energy density at C/3: 230 Wh/l Cycle life at 80% DOD: 1000 Cycles Sources: (1) D. Howell, Energy Storage Research and Development, Annual Progress Report 2006 (Washington, D.C.: Office of FreedomCAR and Vehicle Technologies, U.S. Department of Energy, 2007) (2) FreedomCAR and Fuel Partnership and United States Advanced Battery Consortium (USABC), Electrochemical Energy Storage Technical Team Technology Development Roadmap (Southfield, MI: USCAR, 2006)

7 Why Battery Thermodynamics and Phase Diagrams? Thermodynamics and phase diagrams govern battery performance Thermal management of batteries (Heat dissipation and temperature distribution) Battery safety (thermal runaway) Structural changes in active materials Surface energies (nano-micro) Synthesis of complex ceramic materials

8 Lithium Ion Batteries Operation Graphite LiCoO 2 Presently: Anode: graphitic C; Electrolyte: LiPF 6 in organic carbonate solvents; Cathode: Co-based LiMO 2

9 Source: M. Winter, Univ. Münster

10 German Research Foundation, Priority Programme 1473 Materials with New Design for Improved Lithium Ion Batteries - WeNDeLIB DFG Schwerpunktprogramm 1473, Kick-Off-Treffen, Werkstoffe mit neuem Design für verbessertelithium-ionen-batterien - WeNDeLIB Started in October 2010 Program Commission: Hans Jürgen Seifert Karlsruher Institut für Technologie (Chair) Rainer Schmid-Fetzer Technische Universität Clausthal (Co-Chair) Martin Winter Universität Münster (Co-Chair) Nicola Hüsing Universität Salzburg Andreas Gutsch Li-Tec, Kamenz, now with KIT Bengt Hallstedt RWTH Aachen Ingo Steinbach ICAMS, Bochum International Member: Alexandra Navrotsky University of California, Davis 13 joint projects (36 projects in total) + coordinator project

11 German Research Foundation, Priority Programme 1473 Materials with New Design for Improved Lithium Ion Batteries - WeNDeLIB Vision of this priority program: Coupling of materials thermodynamics and kinetics and modelling of materials design for innovative lithium ion batteries Ideal case: Complete design of battery before the experimental work or processing starts in the lab or in industrial operation Still a long way to go - We introduce a new interdisciplinary concept for LiB (no international program to be compared with this approach)

12 - Scientific Focus - Interdisciplinary Work Correlation of: Materials - Thermodynamics, - Constitution, - Kinetics Crystal chemistry, Microstructure, Innovative Materials Synthesis Electrochemical performance and safety of cells / batteries

13 Approach by electrochemical cell reaction equations

14 Approach by electrochemical cell reaction equations

15 Approach by phase diagrams Al Li yin Li y Al

16 Electrochemical conversion mechanism X = O, N, F, S, P M n X m ne n Li M 0 n Li X m n M. Armand et al., Nature, 2008, 451: Cu-Fe-O electrodes for LIB exhibit Fe-oxides: high theoretical capacity Cu-oxides: cycling stability CuO 2e 2 Li Cu 0 Li2O

17 Calculated Li-Cu-O system (CALPHAD result); isothermal section 25 C

18 Calculated Li-Cu-O System, equilibrium voltages Thermodynamic Calculations 25 C

19 More relationships Thermodynamics - Phase Diagrams - Electrochemistry Li x AN CA discharge AN Li x CA

20 More relationships Thermodynamics - Phase Diagrams - Electrochemistry Full lithium ion cell discharge reaction Li x discharge AN CA Free energy of the full reaction is: AN Li G( x, T ) n F E0( x, T ) x CA Free energy of the full reaction can be written: G( x, T) H ( x, T ) TS( x, T ) Neglecting T-dependence: G0 ( x, T ) H ( x) TS( x) Combining equations: E0( x, T ) n F H S E0( x, T ) T x Open circuit voltage Charge number (n=1 for Li + ) Faraday constant Heat and entropy of reaction Temperature slope of E 0 (x,t) S E0( x, T ) ( x) F T x H E0( x, T ) ( x) F E0( x, T ) T T x

21 In-situ technique entropymetry and phase diagrams OCV for one specific temperature S x x Note: Half cells measured Open circuit voltage of Li x CoO 2 Entropy of Li intercalation in Li x CoO 2 S 1 0 F 1 0 E0( y, T ) T y dy Li x CoO 2 Phase diagram Yazami et al. in Lithium Ion Rechargeable Batteries, WILEY-VCH (2010)

22 Reversible and irreversible heat during cell reaction Q r with S TS x) I nf E F ( 0 Reversible heat generation ( x, T ) T x Q I 2 irr R i Irreversible heat generation Q Q r Q irr Total heat generation + side reactions

23 40Ah pouch cell Cathode material: Li(Ni 1/3 Mn 1/3 Co 1/3 )O 2 NMC Anode material: graphite B. Ketterer, U. Karl, D. Möst, S. Ulrich, Wissenschaftliche Berichte FZKA 7503 (2009)

24 40Ah cell with eight thermocouples measured in Accelerating Rate Calorimeter (ARC)

25 Isothermal cycling of a 40Ah pouch cell Discharge parameter: - method: constant current (CC) - U min = 3,0V - I = 5A C/8-rate Charge parameter: - method: constant current, constant voltage (CCCV) - U max = 4,1V - I = 5A C/8-rate - I min = 0.5A at room temperature temperature coefficient Procedure like in: H.-B. Ren, et. al., Int. J. Electrochem. Sci. 6, p (2011) A.K. Shukla, T.P. Kumar, Current Sci. 94, p (2008)

26 Temperature measurements on a 40Ah pouch cell

27 Discharge parameter: - method: constant current (CC) - U min = 3,0V - I = 5A C/8-rate Charge parameter: - method: constant current, constant voltage (CCCV) - U max = 4,1V - I = 5A C/8-rate - I min = 0.5A at room temperature Adiabatic cycling of a 40Ah pouch cell temperature coefficient Procedure like in: H.-B. Ren, et. al., Int. J. Electrochem. Sci. 6, p (2011) A.K. Shukla, T.P. Kumar, Current Sci. 94, p (2008)

28 Temperature measurements on a 40Ah pouch cell TC sample TC 1 Temperature ( C) TC 2 TC 3 TC 4 TC 5 TC 6 TC 7 TC 8 TC Cathode TC Anode Time (min)

29 Li-Mn-O System Thermodynamically stable phases in the Li-Mn-O system. Stoichiometric LiMn 2 O 4 (c) Cation-mixed Li 1+x Mn 2-x O 4 (c); 0 < x 1/3 Li 4 Mn 5 O 12 Mn-rich Li 1-x Mn 2+x O 4 (t); 0 < x < ~0.1 Mn-deficient Li 1 Mn 2-x O 4 (c); x = 1/4 Thermodynamically unstable phases in the Li-Mn-O system. De-lithiated Li 1-y Mn 2 O 4 Lithiated Li 2 Mn 2 O 4 (t) Oxygen-deficient Li 1+x Mn 2-x O 4-δ ; δ>>0 Mn-deficient LiMn 2-x O 4 (c); 0 < x < 1/4 Oxygen-rich Li 2 Mn 4 O 9 (c) Cation-deficient Li 1-x Mn 2-y O 4 (c)

30 Li-Mn-O System R. Huggins, Advanced Batteries, Springer 2011

31 Li-Mn-O System Phase relationships in the system LiMnO 2 Li 2 MnO 3 - λ-mno 2 and subsystem LiMn 2 O 4 -Li 4 Mn 5 O 12 Li 2 Mn 4 O 9 (Yonemura et al. 2004).

32 Li-Mn-O System Temperature-Composition Ratio Section [1999 Pau] Samples prepared using the solid state method Phase diagram investigated at po 2 =0.21 atm [1999 Pau] Chem. Mater., 11 (1999),

33 Li-Mn-O System p(o 2 )=0.21 atm LiMn 2 O 4 zli 2 MnO 3 + Li 1-2z Mn 2-z O 4-3z-y (tet) + (y/2)o 2 33

34 550 o C Isothermal Li-Mn-O Section System at p(o 2 )=0.21 atm

35 800 o C Isothermal Li-Mn-O Section System at p(o 2 )=0.21 atm

36 Li-Mn-O System Tie-Triangle Movement at p(o2)=0.21 atm [1996Gao] Gao and Dahn, J. Electrochem. Soc., 143(6), , 1996

37 Li-Mn-O System Phase Transformations for Stoichiometric LiMn 2 O 4 LiMnO 2 + Li x Mn 3-x O 4 LiMnO 2 + Li x Mn 3-x O 4 + Li 1-x Mn 2+x O 4 (tet) LiMnO 2 + Li 1-x Mn 2+x O 4 (tet) LiMnO 2 + Li 1-x Mn 2+x O 4 (tet) + Li 2 MnO 3 Li 1-x Mn 2+x O 4 (tet) + Li 2 MnO 3 Li 1-x Mn 2+x O 4 (tet) + Li 1+x Mn 2-x O 4 (cub) + Li 2 MnO 3 Li 1-x Mn 2+x O 4 (tet) + Li 1+x Mn 2-x O 4 (cub) Li 1-x Mn 2+x O 4 (tet) + Li 1+x Mn 2-x O 4 (cub) + Mn 2 O 3 Li 1+x Mn 2-x O 4 (cub) + Mn 2 O 3

38 Enthalpy of Drop Solution of Li 1+x Mn 2-x O 4-δ Sodium Molybdate, 700 C AlexSys, SETARAM High Temperature Calvet Calorimeter

39 Enthalpy of Drop Solution of Li 1+x Mn 2-x O 4-δ Sample Number DROP 1 DROP 2 DROP 3 DROP 4 DROP 5 Date 08. Mai 08. Mai 08. Mai 08. Mai 08. Mai Mass pellet (mg) 6,00 5,14 6,10 6,62 4,85 T(room) ( C) 23,90 24,10 24,20 24,10 24,20 T(cal.) ( C) 700,40 700,40 700,40 700,40 700,40 Formula weight (g/mol) 180, , , , ,815 Moles of LiMn2O4 (mol) 0, , , , , Peak Area [µv.s] 1832, , , , ,3320 Calibration factor from Al 2 O 3 calibration[j/µv.s] 0, , , , , Measured Heat Effect (kj/mol) 255, , , , ,5781 Accepted Measurement DROP 6 DROP 7 DROP Mai 09. Mai 09. Mai 5,35 4,83 5,59 24,50 24,30 24,20 700,40 700,40 700,40 180, , ,815 0, , , , , ,2630 0, , , , , ,

40 Commercial cathode materials Olivine structure Layered structure Spinel structure LiFePO 4 : 160 mah/g LiCoO 2 : 160 mah/g Spinel LiMn 2 O 4 : 100 mah/g Gravimetrical energy densities (capacities)

41 Li-Fe-P-O System LiFePO 4 - Stable phase? Ong et al. (2008)

42 Li-Fe-P-O System LiFePO 4 - Stable phase? Ong et al. (2008)

43 Li-Fe-P-O System Kang and Ceder (2009)

44 Thermodynamics of Lithium Battery Materials - Materials Thermodynamics, Phase Diagrams and Electrochemistry to be simultaneously investigated - Fundamental for electrochemical cell performance, understanding of thermal and safety behavior and for preparation of cathode materials - Thermodynamics and phase diagrams even for the most important systems e.g. Li-Co-O, Li-Mn-O and Li-Fe-P-O to be investigated in more detail Gunnar Eriksson Symposium 2012

45 Li-Mn-O System Phase Transformations for Stoichiometric LiMn 2 O 4 LiMnO 2 + Li x Mn 3-x O 4 LiMnO 2 + Li x Mn 3-x O 4 + Li 1-x Mn 2+x O 4 (tet) LiMnO 2 + Li 1-x Mn 2+x O 4 (tet) LiMnO 2 + Li 1-x Mn 2+x O 4 (tet) + Li 2 MnO 3 Li 1-x Mn 2+x O 4 (tet) + Li 2 MnO 3 Li 1-x Mn 2+x O 4 (tet) + Li 1+x Mn 2-x O 4 (cub) + Li 2 MnO 3 Li 1-x Mn 2+x O 4 (tet) + Li 1+x Mn 2-x O 4 (cub) Li 1-x Mn 2+x O 4 (tet) + Li 1+x Mn 2-x O 4 (cub) + Mn 2 O 3 Li 1+x Mn 2-x O 4 (cub) + Mn 2 O 3

46 Li-Ni-Mn-Co-O System Phase compositions in the Li[Mn 1.5 Ni 0.5 ]O 4 -Li 2 MnO 3 -Li[Mn 0.5 Ni 0.5 ]O 4 system (Park 2007). Composition triangle in the system LiNiO 2 LiMnO 2 Li[Li 1/3 Mn 2/3 ]O 2. Bold lines represent the compositions which have been reported as single phase via a high temperature solid state reaction Zhang et al. (2008).

47 Li-Ni-Mn-Co-O System Triangle system Li 2 MnO 3 -LiMnO 2 -LiNiO 2 (Park 2005). Bold line indicates Mn oxidation state of +4. LiMnO 2 -LiCoO 2 -LiNiO 2 -Li 2 MnO 3 phase diagram, b) Section LiNi 1/2 Mn 1/2 O 2 -LiCoO 2 -Li 2 MnO 3

48 Li-Mn-O System

49 Li-Mn-O System Log p(o 2 Pa) = -2.3 Exo Heating 5 C / min 3LiMn 2 O 4 3LiMnO 2 + Mn 3 O 4 + O % theoretical weight loss 49

50 Li-Mn-O System Reaction of stoichiometric LiMn 2 O 4 at Log(pO 2 )=-2.3 not indicated in the critically evaluated potential diagram for stoichiometric LiMn 2 O 4 50

51 Li-Mn-O System Mn 3 O 4 LiMnO 2 3LiMn 2 O 4 3LiMnO 2 + Mn 3 O 4 + O 2 51

52 Li-Mn-O System Log p(o 2 Pa) = -2.3 Exo Heating 3LiMn 2 O 4 3LiMnO 2 + Mn 3 O 4 + O 2 52

53 Li-Mn-O System Reaction temperature determined as first deviation of the 1st derivative of weight loss from baseline Reaction temperature at log(po 2 )=-2.3 is C 3LiMn 2 O 4 3LiMnO 2 + Mn 3 O 4 + O 2 53

54 Thermodynamics of lithium ion batteries Hans J. Seifert Institute for Applied Materials Applied Materials Physics (IAM-AWP) KIT University of the State of Baden-Wuerttemberg and National Research Center of the Helmholtz Association

55 - SPP1473, Scientific Aims - Materials - Thermodynamics, - Phase Diagrams, - Kinetics Micro- and Nanomaterials Crystal structures, Crystal chemistry, Microstructure, Reactivity Electrochemical performance and safety of cells / batteries

56 Li-Fe-P-O System Kang and Ceder (2009)

57 Li-Fe-P-O System Ong et al. (2008)

58 Dodd et al. (2006) Li-Fe-P-O System

59 Li-Mn-O System Detailed phase relationships in the subsystem LiMn 2 O 4 -Li 4 Mn 5 O 12 Li 2 Mn 4 O 9 (Yonemura et al. 2004).

60 Li-Mn-O System Temperature-Composition Ratio Section in the Li-Mn-O System p(o 2 )=0.21 atm [1999Pau] Paulsen and Dahn, Chem. Mater., 11, ,

61 Lithium Ion Battery discharging charging material of anode oxidized / material of cathode reduced material of anode reduced / material of cathode oxidized

62 Li-Mn-O System

63 R. Huggins, Advanced Batteries Li-Mn-O System

64 Heat generation rates Sources of heat generation: 1. The reversible heat released (or absorbed) by the chemical reaction of the cell 2. The irreversible heat generation by ohmic resistance and polarisation 3. The heat generation by side reactions, i.e. parasitic/corrosion reactions and chemical shorts S. Hallaj, H. Maleki, J.S. Hong, J.R. Selman, J. Power Source 83, p.1-8 (1999)

65 C p, eff measurement on a 40Ah pouch cell U = 4,1V U = 3,0V

66 Separation of reversible and irreversible parts J.R. Selman, S. Hallaj, J. Power Source 97-98, p (2001)

67 Enthalpy of Drop Solution of Li 1+x Mn 2-x O 4-δ 755 C Li-Mn-O Temperature-Composition Ratio Section Samples prepared using a modified Pechini method The homogeneity range of the spinel phase determined using thermogravimmetric analysis at po 2 =0.2 atm Li-rich boundary of the homogeneity range Li 1+x Mn 2-x O 4 should be refined

68 Section in the Li-Mn-O phase diagram (Thackeray et al., 1995). Li-Mn-O System

69 Li-Mn-O System, sample preparation 69

70 Li-Mn-O System Decomposition of LiMn 2 O 4 in air Samples heat treated at 15 hours and quenched in liquid nitrogen 70

71 In-situ technique entropymetry Open circuit voltage as a function of Li concentration in LiMn 2 O 4 Entropy as a function of Li concentration in LiMn 2 O 4 Note: Half cells measured Yazami et al. in Lithium Ion Rechargeable Batteries, WILEY-VCH (2010)

72 2 nd kind phase diagram in the Li-Mn-O system Paulsen and Dahn, 1999 Luo and Martin, 2007 Li-Mn-O System Yonemura et al. 2004

73 German Research Foundation, Priority Program 1473, Materials with New Design for Improved Lithium Ion Batteries - WeNDeLIB Battery Properties Thermal runaway Voltage, potential Capacity, energy- and power density Life time Power- and materials loss during first charge cycle Thermodynamics and Kinetics Oxygen partial pressure, Gibbs free energies of reactions Chemical potentials (of lithium) Phase diagrams, Gibbs free energies Stability of compounds in battery; Materials constitution Formation of SEI; Relative thermochemical stabilities of materials for electrodes and electrolyte

74 ), ( x x x x x T T x E F S ), ( ), ( x x x x x dx T T x E T T x E F H 1 0, max y x x y ), ( dy T T y E F S y ), ( ), ( dy T T y E T T y E F H y Relationships Thermodynamics and Electrochemistry Total change in enthalpy and entropy between two electrode compositions x 1 and x 2 : and with normalization Thermodynamic functions of active materials are needed

75 Battery technology spider chart (USABC) for electrical vehicles (EV) Operating temperature: -40 to +50 C Specific Power Discharge: 300 W/kg Specific Energy at C/3: 150 Wh/kg Selling price at 10k/Jahr: 150$/kWh Power density: 460 W/l Calendar life: 10 years Energy density at C/3: 230 Wh/l Cycle life at 80% DOD: 1000 Cycles Sources: (1) D. Howell, Energy Storage Research and Development, Annual Progress Report 2006 (Washington, D.C.: Office of FreedomCAR and Vehicle Technologies, U.S. Department of Energy, 2007) (2) FreedomCAR and Fuel Partnership and United States Advanced Battery Consortium (USABC), Electrochemical Energy Storage Technical Team Technology Development Roadmap (Southfield, MI: USCAR, 2006)

76 M Winter, J. O. Besenhard, Chem. uns. Zeit 33, p (1999)

77 Li-Cu-Fe-O System Thermodynamic calculations based on the CALPHAD method predict battery performance N. Saunders, I. Ansara (Ed), Cost 507, Report,1994, B. Hallstedt,L.J. Gauckler CALPHAD, 2003, 27: K. Chang, B. Hallstedt, CALPHAD, 2011, 35: equilibrium voltages (OCV) plateau capacities Database development for the Li-Cu-Fe-O System The Cu-Fe-O ternary system assessed by Khvan et al. First calculated phase diagrams in the Li-Cu-O system addressed in present work

78 Isothermal calorimetric measurements on a 16 mah Lithium ion coin cell Discharge parameters: - Method: constant current (CC) - U min = 2.75 V - I = 16 ma 1C-rate Charge parameters: - Method: constant current, constant voltage (CCCV) - U max = 4.25 V - I = 16 ma 1C-rate - I min = 1.6 ma Isothermal Battery Calorimeter (IBC) Cell type: coin cell LIR 2016, Conrad energy (commercial) Capacity: 20 5 mah; Working voltage: 3.6 V

79 Voltage [V] Current [ma] Heat [mw] Isothermal calorimetric measurements on a 16 mah Lithium ion coin cell ,25 4,00 3,75 3,50 3,25 3,00 2, Temperature T env = 20 C Temperature T env = 40 C Charge (16 ma) Time [s] Discharge (16 ma) Voltage [V] Current [ma] Heat [mw] ,25 4,00 3,75 3,50 3,25 3,00 2,75 10 Charge (16 ma) Time [s] Discharge (16 ma)

80 Accelerating Rate Calorimeter (ARC) ARC provides an adiabatic environment in which a sample may be studied under conditions of negligible heat loss heat of reaction: total heat generated: EVARC: Ø: 25cm h: 50cm ESARC: Ø: 10cm h: 10cm

81 Thermodynamics of electrochemical reactions Thermal Runaway electrochemical reaction Gibbs-Helmholtz equation entropic change of electrochem. reaction start of thermal runaway cell catch fire reversible heat S. Tobishima, J.Yamaki, J. Power Source 81-82, p (1999) A.K. Shukla, T.P. Kumar, Current Sci. 94, p (2008)

82 Enthalpy of Drop Solution of Li 1+x Mn 2-x O 4-δ Sodium Molybdate, 700 C AlexSys 1000, SETARAM High Temperature Calvet Calorimeter

83 Enthalpy of Drop Solution of Li 1+x Mn 2-x O 4-δ Sample Number DROP 1 DROP 2 DROP 3 DROP 4 DROP 5 Date 08. Mai 08. Mai 08. Mai 08. Mai 08. Mai Mass pellet (mg) 6,00 5,14 6,10 6,62 4,85 T(room) ( C) 23,90 24,10 24,20 24,10 24,20 T(cal.) ( C) 700,40 700,40 700,40 700,40 700,40 Formula weight (g/mol) 180, , , , ,815 Moles of LiMn2O4 (mol) 0, , , , , Peak Area [µv.s] 1832, , , , ,3320 Calibration factor from Al 2 O 3 calibration[j/µv.s] 0, , , , , Measured Heat Effect (kj/mol) 255, , , , ,5781 Accepted Measurement DROP 6 DROP 7 DROP Mai 09. Mai 09. Mai 5,35 4,83 5,59 24,50 24,30 24,20 700,40 700,40 700,40 180, , ,815 0, , , , , ,2630 0, , , , , ,

84 2 nd kind phase diagram in the Li-Mn-O system Paulsen and Dahn, 1999 Luo and Martin, 2007 Li-Mn-O System Yonemura et al. 2004

85 Li-Mn-O System Chemical potential diagram in the Li-Mn-O system (Tsuji et al. 2005). What to do next: (1) Evaluation; (2) Solution phase modeling; (3) Thermodynamic optimization

86 Li-Mn-O System Experimental Potential Diagram for Stoichiometric LiMn 2 O 4 [2005Tsu] Tsuji et al., J. Chem. Phys. Solids, 66, ,

87 Li-Mn-O System Critically Evaluated Potential Diagram for Stoichiometric LiMn 2 O 4 87

88 Li-Mn-O System Temperature-Composition Ratio and Potential Diagrams LiMn 2 O 4 composition is a vertical line in the temperature-composition ratio diagram p(o 2 )=0.21 atm is a horizontal line in the potential diagram 88

89 Li-Mn-O System Potential diagram at constant Li/Mn ratio p(o 2 )=0.21 atm Li/Mn ratio for LiMn 2 O 4 LiMn 2 O 4 zli 2 MnO 3 + Li 1-2z Mn 2-z O 4-3z-y (tet) + (y/2)o 2 Li 1-2z Mn 2-z O 4-3z-y (tet) LiMnO 2 +(1/3) Mn 3 O 4 + {(1/3)-(y/2)}O 2 [1999 Pau] Chem. Mater., 11 (1999), [2005 Tsu] J. Phys. Chem., Solids. 66 (2005),

90 Commercial cathode material LiMn 2 O 4 Spinel structure Spinel LiMn 2 O 4 : 100 mah/g Gravimetrical energy density (capacity)

91 Dodd et al. (2006) Li-Fe-P-O System

92 Lithium Ion Batteries Operation Solid Electrolyte Interface Separator Graphite LiCoO 2

93 Li-Fe-P-O System Ong et al. (2008)

94 Li-Fe-P-O System

95 CALPHAD Modelling and Simulation Ab-initio covalent ionic Phase Field Kratzer et al., Chelikowsky et al., Phys. Rev. B 14, 556 (1976) interfaces (length scale) mechanical equilibrium (energy scale) transport / diffusion (time scale) + + +

96 Accidents with lithium ion batteries Rechargable battery of a laptop overheating or internal short circuit Fire 3 days after crashtest with EV mechanical impact stationary energy storage overcharging