Li-Ion Batteries Anode Materials (Part 2) - ZSW

Li-Ion Batteries 

Lecture 

Winter Term 2011/12 

Anode Materials (Part 2) 

17 November 2011 

Mario Wachtler 

Zentrum für Sonnenenergie- und Wasserstoff-Forschung 

Baden-Württemberg (ZSW)

Introduction 

Li metal 

Graphite 

Amorphous Carbons 

Titanates 

Lithium storage metals and alloys 

Convertible oxides 

Transition metal oxides 

Summary 

-2- 

111117 | Li-Ion Batteries 2011/12 | Anode Materials 2 | MW 

Contents

-3- 


Titanates 

Overview 

Li-Ti-Spinel Li 4Ti 5O 12 (Li 4/3Ti 5/3O 4, LTO, LTS) 

Li-Ti-Spinel LiTi 2O 4: very difficult to synthesize 

TiO 2: (B), anatase, (rutile), ((brookite)) 

Ramsdellite Li 2Ti 3O 7

Very stable structure 

Frequently found in nature 

Derived from mineral „spinel“ MgAl 2 O 4 

-4- 


Spinel Structure 

General structure: AB 2 O 4 

Cubic close-packed (ccp) oxygen lattice 

With 1 octahedral interstitial site per oxygen and 2 tetrahedral interstitial sites 

per oxygen 

A and B occupy octahedral and tetrahedral sites 

Normal spinel structure: 

Trivalent ions (B) occupying half of the octahedral sites 

Divalent ions (A) occupy 1/8 of the tetrahedral sites

-5- 

Li[Li 1/3Ti 5/3]O 4 


Li 4 Ti 5 O 12 

Spinel Structure 

Li 2[Li 1/3Ti 5/3]O 4 

charge 

+ Li 

(Li +1 

1 

)8a () 16c [Li +1 

1/3 

Ti5/3 

+4 

]16d (O -2 

4 

)32e () 8a (Li +1 

2 

)16c [Li +1 

1/3 

Ti5/3 

+3.4 

]16d (O -2 

4 

)32e 

+ + e- discharge 

-Li + -e-

-6- 

() 8a () 16c [Mn 2 +4 ]16d (O 4 -2 )32e 

(discharge) -Li + -e - ↓↑ + Li + + e - (charge) _ 

(Li 1 +1 )8a () 16c [Mn 2 +3.5 ]16d (O 4 -2 )32e 

↓↑ 

() 8a (Li 2 +1 )16c [Mn 2 +3 ]16d (O 4 -2 )32e 

Crystallographic sites in Wyckoff notation: 

32e positions of oxygen in ccp structure 

16d ½ of octahedral sites 

16c ½ of octahedral sites 

8a ⅛ of tetrahedral sites 

Vacant crystallographic sites 

Spinel Structure and Capacity 

LiMn 2O 4 


Theoretical capacity of LiMn 2 O 4 is limited by the 

amount of extractable Li + and the oxidation state of 

Mn. 

Practically only arount 0.9 Li or 90% of the 

theoretical capacity can be cycled. 

Note that λ-Mn 2 O 4 has no true spinel structure. 

For LiMn 2 O 4 it is possible to insert further Li, at a 

potential plateau of around 3.5 V vs. Li/Li + . 

The theoretical capacity is limited by the amount of 

vacant octahedral Li + insertion sites, and by the 

oxidation state of Mn. 

Since Mn +3 is a Jahn-Teller ion structural 

distortions occur, which deteriorates the cycling 

stability. Therefore this region is not used in Li-ion 

batteries. 

Note that Li 2 Mn 2 O 4 does not have spinel structure 

(tetragonal distortion).

-7- 


Li[Mn 2-xAl x]O 4 

↓↑ 

(Li 0.05 +1 )8a () 16c [Mn 1.95 +4 Al0.05 +3 ]16d (O 4 -2 )32e 


(Li 1 +1 )8a () 16c [Mn 1.95 +3.51 Al0.05 +3 ]16d (O 4 -2 )32e 

↓↑ 

() 8a (Li 2 +1 )16c [Mn 1.8 +3 Al0.2 +3 ]16d (O 4 -2 )32e 


In principle there would be further Li + left 

to be extracted, but there are no transition 

metals left which can be further oxidised 

(Mn is already completely oxidised to 

Mn +4 ) 

I.e. Theoretical capacity is limited by 

oxidation state of transition metals. 

Theoretical capacity is limited by 

oxidation state of transition metals (Mn +3 

cannot be further reduced) and by 

amount of vacant octahedral Li + insertion 

sites (are completely filled).

-8- 

↓↑ 

(Li 1 +1 )8a () 16c [Li 1/3 +1 Ti5/3 +4 ]16d (O 4 -2 )32e 


Li 4/3Ti 5/3O 4 


() 8a (Li 2 +1 )16c [Li 1/3 +1 Ti5/3 +3.4 ]16d (O 4 -2 )32e 

↓↑ 


Further discharge (extraction of Li + ) is not 

possible, since Ti is already in oxidation state 

+4 and cannot be further oxidised. 

Though Ti +3.4 could be further reduced to Ti +3 , 

further charge is not possible, since there are 

no vacant octahedral sites for Li + insertion left. 

I.e. Theoretical capacity is limited by amount 

of available Li-ion insertion sites

Capacity 

Theoretical capacity: 175 mAh/g 

Practical capacity: ~ 150 mAh/g 

→ I.e. half the capacity of graphite 

Charge / discharge profile 

-9- 



Properties 

Charge and discharge occurs at a constant 

potential at approx. 1.5 V vs. Li/Li + 

→ I.e. approx. 1.3 V higher than graphite 

Energy density 

→ Due to lower capacity and higher potential 

resulting in lower cell voltage, the energy 

density of a Li-ion cell with LTO is 

significantly reduced compared to a Li-ion 

cell with graphite. 

T. Ohzuku, A. Ueda, N. Yamamot; J. Electrochem. Soc. 142 (1995), 1431.

Cycling stability: 

Volume change during Li insertion are 

Thermal behaviour: 

LTO shows a high thermal stability 

without strong exothermic peaks 

→ Better thermal safety than graphite 

-11- 



Properties 

DSC – TG of charged anode materials 

TG /% 

100 

95 

90 

85 

80 

75 

70 

TG Exothermal 

Graphite 


100 200 300 400 500 

Temperatur /°C 

Source: C. Täubert, M. Fleischhammer, H.-Y. Tran, P. Axmann, 

M. Wohlfahrt-Mehrens (ZSW) 

DSC /(mW/mg) 

exo 

[2] 

[1] 

[1] 

[2] 

1.5 

1.0 

0.5 

0.0

Rate capability 

LTO works in a potential region where the 

electrolyte is stable, and no SEI is formed. 

The absence of SEI formation keeps the 

electrode impedance low. 

(For comparison: graphite and amorphous 

carbons are filmed with a SEI giving rise to 

additional electrode impedance.) 

Due to open spinel structure and absence of 

SEI very high rate capabilities are 

achievable. 

-12- 



Properties 

Toshiba Super Charge Ion Battery (SCiB) 

Product Data Sheet, Toshiba, 2010 (www.toshiba.com/scib) 

Stability window of 

electrolyte 

5 

4 

LiMn LiMn2O 2O 4 

3 

2 

1 

0 

Li 

LiCoO 2 Li(Ni,Mn,Co)O 2 

Li(Ni,Co,Al)O 2 

LiFePO 4 

Amorphous 

carbon 

Graphite Si 

5 

4 

3 

2 

Li Li4Ti 4Ti5O 5O 12 

1 

0 

SEI-free 

SEI film 

formation

-13- 



Properties 

Electrolyte compatibility and low temperature behaviour 

LTO is a SEI-free electrode 

Since SEI-formation is not required other electrolyte compositions can be used than for 

graphite anodes, and electrolytes with improved low temperature performance can be 

used. (For graphite anodes an effective SEI is required, therefore nearly all electrolytes 

contain ethylene carbonate (EC) as solvent and often additional film-forming electrolyte 

additives). 

→ Better low temperature performance achievable than with graphite 

Toshiba Super Charge Ion Battery (SCiB) 

Product Data Sheet, Toshiba, 2010 (www.toshiba.com/scib)

Introduction 


Graphite 


Titanates 




Summary 

-14- 


Contents

-15- 


Lithium Storage Metals 

Principle: 

Reversible “alloy” formation 

More correctly: formation of intermetallic compounds 

M + x Li + + x e − Li x M

-16- 

Capacities 

Background columns: specific charge referred to mass of unlithiated material 

Foreground columns: specific charge referred to mass of lithiated materials 



Background columns: charge density referred to volume of unlithiated material 

Foreground columns: charge density referred to volume of lithiated materials 

Volume changes during 

charge / discharge 

Background columns: volume per charge for lithiated materials 

Foreground columns: volume per charge for unlithiated materials 

The large volume changes cause problems 

with mechanical stability (cracking, crumbling 

= “decrepitation”) and limit cycling stability.

Course Sn 

-17- 

Before cycling 

Fine Sn 


Electrode Disintegration Due to Volume Changes 

After 2 cycles 

Before cycling After 2 cycles 




J. Yang, M. Wachtler, M. Winter, J.O. Besenhard, 26. GDCh-Hauptversammlung und 100-Jahrfeier der GÖCh; Wien, 1997

-18- 

Lithium Storage Metals and “Alloys” 

Increase of cycling stability: 

• Smaller particle size 

• Thin films 

• Nano-structuring 

• Amorphous materials 

• „Dilution“ or stabilisation in 

compounds with active or inactive 

secondary components (e.g. 

oxides 

• Reactive binders, which form 

strong bonds with active material 

and hold material together 


Example: Si nanowires 

C.K. Chan, H.L. Peng, G. Liu, K. McIlwrath, X.F. Zhang, 

R.A. Huggins, Y. Cui, Nature Nanotech. 3 (2008), 31.

-19- 

Lithium Storage Metals and “Alloys” 

Ultrahigh capacities (Sn up to 1000 mAh/g, Si up to 

3600 mAh/g) 

Usually low cycling stabilities due to large volume 

changes (several 100%) during charge/discharge, 

which may result in mechanical destruction of 

electrode material 

Improvement of cycling stability by using finely 

dispersed materials or thin films and by using 

amorphous materials (single phase reactions 

instead of two phase reactions) 

Often high irreversibly capacities 

Potential region between 1 und 0 V vs. Li/Li + 

depending on metal (e.g. Si: 600 – 0 mV) 

Safety behaviour not fully assessed yet 

Often used in composites with carbon / graphite or 

as oxide (in order to „dilute“ volume changes and 

stabilise structure and morphology of metal / alloy) 


Potential / V vs. Li/Li + 

1,2 

1,0 

0,8 

0,6 

0,4 

0,2 

Sn 

0,0 

0,0 0,2 0,4 0,6 0,8 1,0 1,2 1,4 1,6 

Capacity / Ah g(AM) -1 

M. Wachtler, M. Winter, J.O. Besenhard; J. Power 

Sources 105 (2002), 151. 

Si 

C.K. Chan, H.L. Peng, G. Liu, K. McIlwrath, X.F. Zhang, 

R.A. Huggins Y. Cui; Nature Nanotech. 3 (2008), 31.

-20- 

room temperature 

overcharge 

(Li plating) 

Reaction Mechanism of Sn 

fully charged 


charge 

discharge 

fully discharged 

Binary alloy phase diagrams 

(2nd edition plus updates, 

electronic release); ASM Int., 

Materials Park, OH, USA, 1996.

Binary alloy phase diagrams (2nd edition plus 

updates, electronic release); ASM Int., Materials 

Park, OH, USA, 1996. 

-21- 

Reaction Mechanism of Sn 

charge 

discharge 


RT 

(a) 

Potential / V vs. Li/Li + 

1.2 

1.0 

0.8 

1 

20.6 

3 

0.4 

0.2 

0.0 

4 

0.02 mA cm -2 

0.05 mA cm -2 

0.1 mA cm -2 

0.2 mA cm -2 

0.5 mA cm -2 

4 

3 2 

0 

-2 0 2 4 6 

0.0 0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6 

Time / min 

Capacity / Ah g(AM) -1 

M. Wachtler, M. Winter, J.O. Besenhard, J. Power Sources 

105 (2002), 151. 

(1) Sn, (2) Li 2 Sn 5 , (3) LiSn, (4) Li 22 Sn 5 * 

(12) Sn + 0,4 Li + + 0,4 e − 0,2 Li 2 Sn 5 

(2 3) 0,2 Li 2 Sn 5 + 0,6 Li + + 0,6 e − LiSn 

(34) LiSn + 3,4 Li + + 3,4 e − … 0,2 Li 22 Sn 5 

*sometimes different stoichiometries are given for fully 

lithiated state: Li 17 Sn 4 , Li 21 Sn 5 

1 

OCV / mV 

200 

150 

100 

50

-22- 

Lithium Storage “Alloys” (Intermetallic Phases) 

Containing 2 or more constituents 

Active/active composites: 

both constituents can form an alloy with Li 

e.g. SnSb 1 / 5 Li 22 Sn 5 + Li 3 Sb 

Active/inactive composites: 

only one constituent forms an alloy with Li 

e.g. Cu 6 Sn 5 Li 22 Sn 5 + 6 Cu 

Multiphase active/inactive composites: 

only one phase reacts with Li 

e.g. Sn 2 Fe/SnFe 3 C 2 / 5 Li 22 Sn 5 + Fe + SnFe 3 C 

111117 | Li-Ion Batteries 2011/12 | Anode Materials 2 | MW

-23- 

Reconstitution Reactions / 

Conversion Reactions 

Some phases grow and others disappear 

Formation React. 

A + B = AB 

Compound AB is formed 

from ist atomic 

constituents 


Reaction Mechanisms 

General Overview 

Displacement 

Reactions 

A + BX = AX + B 

One component is 

displaced from lattice 

while another is inserted 

Extrusion 

Reactions 

A + BX = AX + B 

Displacement reactions, 

where one interstitial 

species is extruded from 

stable host lattice and 

replaced by newly 

inserted species 

Insertion Reactions 

Topotactic insertion of guest species into 

interstitial sites of host lattice; structure of 

host lattice does not change significantly 

Multiphase 

Insertion React. 

xA + BX = A x BX 

Two phases with different 

concentrations of guest 

species in equilibrium; 

motion of 2-phase 

interface 

Intercalation 

Reactions 

Insertion reactions with 

2-dimensional character 

Single-Phase 

Insertion React. / 

Solid Solution R. 

δA + BX = A δ BX 

0 ≤ δ≤x 

Continuous change of 

phase composition by 

gradual insertion of guest 

species

-24- 



For intermetallic phases („alloys“) both insertion and conversion reactions are observed. 

Insertion reactions: 

Topotactic reactions (i.e. crystal structure does not change) 

Low volume changes 

Good reversibility (cycling stability) 

But for intermetallic phases insertion reactions are limited to small amounts of inserted Li, 

i.e. to small capacity 

Conversion reactions: 

Recrystallisation of system 

Usually larger volume differences between product and educt phases mismatch of 

crystalline phases 

Lower cycling stability 

High capacity 

In conclusion, it would be desirable to limit cycling to pure inserion range, but the practical 

capacities are too low. 


SnSb 

(rhombohedrally distorted 

rock-salt structure) 

-25- 


Reaction Mechanism of SnSb 

Sb 

Sn 

Li 

Insertion 

+ 2 Li + + 2 e – 

Extrusion 

+ 3 Li + + 3 e – 


Li 2 SnSb 

+ Li + + e – 

Li 3 Sb 

Extrusion 

+ Sn 

Formation 

+ x Li + + x e – 

Li x Sn

-26- 



SnSb: 

No ternary phases LixSnSb observed No insertion 

SnSb + 3 Li + + 3 e – ↔ Li3Sb + Sn Extrusion 

Sn + 22 / 5 Li + + 22 / 5 e – ↔ … ↔ 1 / 5 Li22Sn5 Formation 

M. Wachtler, M. Winter, J.O. Besenhard; J. Power Sources 105 (2002), 151. 

InSb: 

InSb + x Li + + x e – ↔ LixInSb with x = 0.27 Insertion 

LixInSb + (3-x) Li + + (3-x) e – ↔ Li3Sb + In Extrusion 

In + 7 / 4 Li + + 7 / 4 e – ↔ … ↔ 1 / 4 Li7In4 Formation 

K.C. Hewitt, L.Y. Beaulieu, J.R. Dahn; Electrochem. Solid-State Lett. 3 (2000), 13. 

Cu 2 Sb: 

Cu 2 Sb + Li + + e – ↔ LiCuSb + Cu Extrusion 

LiCuSb + x Li + + x e – ↔ Li 1+x CuSb (with 0 < x < ~0.5) Insertion 

Li 1+x CuSb + (2-x) Li + + (2-x) e – ↔ Li 3 Sb + Cu Extrusion 

S. Matsuno, M. Noji, T. Kashiwagi, M. Nakayama, M. Wakihara; J. Phys. Chem. C 111 (2007), 7548. 


Indication of relative 

atomic composition: 

A xB yC z 

with x + y + z = 1 

-27- 

Isothermal Ternary Phase Diagrams 

Triangular Coordinate System 

x (concentration of A) 

0,8 

0,6 

0,4 

0,2 

1,0 

0,0 

0,0 

A 

0,2 0,4 0,6 0,8 1,0 

B 


0,0 

C 

1,0 

0,8 

y (concentration of B) 

0,6 

0,4 

z (concentration of C) 

0,2

-28- 

2-phase tie-line: 

mixture of phases 

A 2 BC and A 


Phases and Multiphase-Regions 

Ternary phase A 2 BC 

0,8 

0,6 

0,4 

A 2BC 

0,2 

1,0 

0,0 

0,0 

A 

0,2 0,4 0,6 

AB 

0,8 1,0 

B 

2-phase tie-line: 

mixture of phases A 2 BC and AB 


0,0 

C 

1,0 

0,8 

0,6 

0,4 

0,2 

Binary phase AB 

3-phase region: 


A 2 BC and A and B 

3-phase region: 


A 2 BC and AB and B

-29- 

0,8 

NaCl 

0,6 

0,4 

0,2 


Construction from Thermodynamic Data 

0,0 

Cl 

1,0 

0,0 

0,0 

Na 

0,2 0,4 0,6 0,8 1,0 

Ni 

1,0 

0,8 

NiCl 2 

0,6 

0,4 

0,2 


Assume a ternary system Na, Ni, Cl with two binary 

phases NaCl and NiCl, and without ternary phases. 

(ZEBRA battery Na | Na-β-alumina | NaAlCl 4 , NiCl 2 ) 

Total diagram must be divided into triangles. 

Here there are two possibilities: 

Tieline between NaCl and Ni or 

Tieline between NiCl 2 and Na 

Formulate virtual reaction (in intersection): 

2 Na + NiCl 2 = 2 NaCl + Ni 

Calculate standard Gibbs free energy change for this 

reaction: 

ΔG r ° = 2ΔG f ° (NaCl) – ΔG f ° (NiCl2) 

= 2(–360,25 kJ/mol) – (–221,12 kJ/mol) 

= –137,12 kJ/mol 

ΔGr° < 0, therefore reaction will tend to go to the 

right, and tieline between NaCl and Ni will be more 

stable than tieline between NiCl 2 and Na.

-30- 


Reaction Mechanism of Cu 2Sb 

Isothermal ternary phase diagram 

(room temperature) 

S. Matsuno, M. Noji, T. Kashiwagi, M. Nakayama, M. Wakihara; 

J. Phys. Chem. C 111 (2007), 7548. 


(1) 

(2) (3) 

Proposed reaction mechnism: 

(1) Cu 2 Sb + Li LiCuSb + Cu 

3-phase region (flat potential) 

from graphite as 

conductive 

additive, not from 

Cu 2 Sb). 

(2) LiCuSb + x Li Li 1+x CuSb (with 0 < x < ~0.5) 

Solid solution reaction (sloping potential profile) 

(3) Li 1+x CuSb + (2-x) Li Li 3 Sb + Cu (with x = ~0.5) 

3-phase region (flat potential)

-31- 

Composites of Graphite / Carbon with 

Lithium Storage Metals / Alloys 

Motivation: 

Combine cycling stability of graphite with high capacity of metal / alloy. 

In reality: 

Increase of capacity of graphite by adding metal / alloy with high storage capacity 

Better cycling stability than for pure metal / alloy (but lower than for pure graphite): 

- since overall volume expansion remains low (metal / alloy is diluted by graphite) 

- graphite can act as buffer for expanding metal / alloy 

- since aggregation of metal (Sn) during cycling is prevented by second phase 

(graphite) 

Usually higher irreversible capacity than for graphite 

Examples: 

Graphite + Si, SiO x , Sn, SnO x , SnSb, … 

Amorphous carbon + Si, … 

Graphite + amorphous carbon + Si, … 


-32- 

Composites of Graphite with Lithium Storage Metals 

Graphite / Si Composite 

7.1 wt.% nano-sized Si deposited on graphite 

M. Holzapfel, H. Buqa, F. Krumeich, P. Novák, F.-M. Petrat, C. Veit; Electrochem. Solid-State Lett. 8 (2005), A516. 


Higher capacity than graphite 

Better cycling stability than pure Si

Introduction 


Graphite 


Titanates 




Summary 

-33- 


Contents

Compounds: 

-34- 

Convertible Oxides 

Oxides of Main Group Elements: Sn, Si, Sb, … 

Oxides of Li storage metals: SnO, SnO 2 , SiO 2 , GeO 2 , PbO, ZnO, CdO, B 2 O 3 , Al 2 O 3 , 

Sb 2 O 3 , … 

Amorphous oxides and glasses: e.g. SnB x P y Al z O w ATCO (amorphous tin composite 

oxide, Fuji Industries) 

Sulphides, Selenides, … 

Reaction Mechanism: 

1 st step: Irreversible reduction of oxide to metal and Li 2 O: 

MO x + 2x Li + + 2x e – M + x Li 2 O 

2 nd step: Reversible alloy formation of metal with Li 

M + y Li + + y e – Li y M 

E.g.: SnO 2 : SnO 2 + 4 Li + + 4 e – Sn + 2 Li 2 O 

5 Sn + 22 Li + + 22 e – … Li 22 Sn 5 


-35- 


Convertible Oxides 

Properties 

Large irreversible capacities during first charge due to irreversible reduction of 

oxide. 

Lower reversible capacity than for pure Li storage metal, since additional 

inactive compounds are present which contribute weight without adding Li 

storage capacity. 

Improved cycling stability compared to pure Li storage metal: 

Metal is present as nano-grains which are finely dispersed in a Li 2 O matrix. 

Small grain size keeps absolute volume changes of single particles/grains 

small 

Inactive Li 2 O matrix buffers volume changes of Sn during charge/discharge. 

For Sn: Inactive components help to keep Sn grains separated and to prevent 

growth of Sn grains. (Pure nano-dispersed Sn tends to agglomerate during 

repeated cycling and to form larger particles. Large particle may cause 

problems with low cycling stability due to large volume changes.)

Sn: 

-36- 

Sn, SnO, SnO 2 

Theoretical Reversible and Irreversible Capacities 

Sn + 22/5 Li + + 22/5 e – … 1/5 Li 22 Sn 5 

Capacity (reversible): 994 mAh/g (Sn) 

SnO: 

SnO + 2 Li + + e – Sn + Li 2 O 

Capacity (irreversible): 398 mAh/g (SnO) 


Capacity (reversible): 876 mAh/g (SnO) 

SnO 2 : 

SnO 2 + 4 Li + + 4 e – Sn + 2 Li 2 O 

Capacity (irreversible): 711 mAh/g (SnO2) 


Capacity (reversible): 783 mAh/g (SnO2) 


Isothermal Ternary Phase Diagram 

R.A. Huggins: Advanced Batteries, 

Springer, New York (USA), 2009, pp. 154-156. 

-37- 

SnO 

Thermodynamic Considerations 


Theoretical coulometric titration curves at 25°C 

Calculation of Equilibrium Potentials: 

2 Li + SnO = Sn + Li 2 O 

Δ r G° = Δ f G°(Li 2 O) – Δ f G°(SnO) 

= –562,1 – (–256,8) kJ/mol = –305.3 kJ/mol 

E = –Δ r G°/zF 

= – (–306,0 kJ/mol) / (2 · 96485 As/mol) = 1.58 V 


… as for pure Sn

-38- 

SnO 

Theoretical and Practical Charge / Discharge Profiles 

Theoretical coulometric titration curves at 25°C Practical charge / discharge profile 

~400 ~800 ~1200 mAh/g 

R.A. Huggins: Advanced Batteries; 

Springer, New York (USA), 2009, p. 156. 


I.A. Courtney, J.R. Dahn; 

J. Electrochem. Soc. 144 (1997), 2045.

Introduction 


Graphite 


Titanates 




Summary 

-39- 


Contents

Oxides of transition metals: Mn, Fe, Co, Ni, 

Cu, … 

MOx + 2x Li + + 2x e – M + x Li2O 

z.B: CoO: CoO + 2 Li + + 2 e – Co + Li2O 

• High discharge potential 

• Large hysteresis between charge and 

discharge (low energy efficiency) 

-40- 


Transition Metal Oxides 

Formation of a „mosaic“ of nano-scale 

metal in a Li 2 O matrix 

e.g. HRTEM image of lithiated CuO: 

Upper right: P. Poizot, S. Laruelle, S. Grugeon, L. Dupont, B. Beaudoin, J.- 

M. Tarascon; C. R. Acad. Sci. Paris, Série II2, Chimie 3 (2000), 681. 

Bottom right: A. Débart, L. Dupont, P. Poizot, J.-B. Leriche, J.M. Tarascon, 

J. Electrochem. Soc. 148 (2001), A1266.

Introduction 


Graphite 


Titanates 




Summary 

-41- 


Contents

-42- 

Material 

Graphite 

Amorphous Carbon / 

Hard Carbon 

LTO 


Si 

Li * 

Comparison of Anode Materials 

Energy 

Density 

Power 

density 

* Requires special, charged cathode materials 


Safety 

Cycling 

stability 

Costs 

per Ah 

Very good Very bad

Graphite 

Li + C 6 = LiC 6 


Li 4 Ti 5 O 12 + Li = Li 7 Ti 5 O 12 

-43- 



Examples 

insertion, intercalation 

insertion 

Sn 

Li + Sn = Li x Sn reconstitution / conversion, formation 

Sb 

Li + Sb = Li 3 Sb reconstitution / conversion, formation 

SnSb 

Li + SnSb = Li 3 Sb + Sn extrusion 


Cu 6 Sn 5 

Li + Cu 6 Sn 5 = Li 2 CuSn + Cu insertion with slight lattice rearrangement, extrusion 

Li + Li 2 CuSn = Li x Sn + Cu reconstitution 

SnO 2 , SnO 

Li + SnO x = Sn + Li 2 O reconstitution / conversion, displacement 


Study of reaction mechanisms with ex-situ or in-situ XRD, Mössbauer spectroscopy, etc.

-44- 

Manufacturer 

Toyota 

Panasonic 

JCS (Johnson Controls & SAFT) 

Hitachi * 

AESC (Nissan & NEC) 

Sanyo * 

GS Yuasa * 

A123 

LG Chem 

Samsung * 

SK 

Toshiba & EnerDel 

AltairNano 

LIB for Automotive Applications 

Type 

metal, elliptic, wound 


metal, cylindric, wound 

metall, cyl./ell., wound 

pouch, prismatic, stacked 



metall/pouch, cyl., wound 



pouch, prismatic, wound 

pouch/metal, prism., wound 



Cathode 

NCA 

NMC 

NCA 

LMO / NMC 

LMO / NCA 

NMC / LMO 

LMO / NMC 

LFP 

LMO 

NMC / LMO 

LMO 

LMO 

LMO 

Anode 

graphite 

amorph. carbon 

graphite 

hard carbon 

hard carbon 

graphite 

hard carbon 

graphite 

amorph. carbon 

graphite 

graphite 

LTO 

LTO 

Electrolyte 

liquid 

liquid 

liquid 

liquid 

liquid 

liquid 

liquid 

liquid 

gel 

liquid 

liquid 

liquid 

liquid 

Li-Tec (Evonik & Daimler) pouch, prismatic, stacked NMC graph. / hard carbon liquid 

Gaia 

Leclanché Lithium 

metal, cylindric, wound NCA / LFP graphite liquid 

pouch, prismatic, stacked various graphite / LTO liquid 

Source: M. Anderman: Tutorial E: Value Proposition Analysis for Lithium-Ion Batteries; Advanced Automotive Batteries Conference, 2009 

Complemented by data for German LIB manufacturers 

* Data unconfirmed

-45- 


Improvement of Anode 

Actual R&D Trends 

Increase of energy density of LIB 

→ Further decrease of electrode potential is not possible (e.g. for graphite), 

since already near potential of Li metal deposition 

→ Increase of capacity: 

Higher utilisation of theoretical capacity (e.g. for graphite) 

New materials: Li storage metals and alloys (Li x Sn, Li x Si, etc.) 

Rechargeable Li metal anode (solve problem of dendritic Li deposition) 

Increase of power density of LIB 

Materials with fast Li insertion (amorphous carbons, titanates with tailored 

morphology, etc.) 

SEI-free materialis (e.g. lithium titanium spinell), but lower cell voltage 

Materials with optimised SEI of low impedance (e.g. artificial SEI) 

Improvement of safety of LIB 

New anode materials with lower reactivity 

Decrease of surface area (e.g. coating of graphite)

-46- 


Further Reading 

Anodes 

R.A. Huggins: Advanced batteries; Springer, New York (USA), 2009. 

J.O. Besenhard (ed.): Handbook of battery materials; Wiley-VCh, Weinheim (Germany), 

1999. 

R.A. Huggins: Lithium Alloy Anodes, pp. 359-382. 

M. Winter, J.O. Besenhard: Lithiated Carbons; pp. 383-418. 

E.Peled, D. Golodnitzky, J. Pencier: The Anode/Electrolyte Interface; pp. 419-456. 

M. Winter, J.O. Besenhard, M.E. Spahr, P. Novak: Insertion Electrode Materials for 

Rechargeable Lithium Batteries; Adv. Mater. 10 (1998), 725.

Thank you for your attention! 

Stuttgart 

Photovoltaics -47- & Solab 

Energy Policy & Energy Carriers 

mario.wachtler@zsw-bw.de 

www.zsw-bw.de 

Zentrum für Sonnenenergie- und Wasserstoff-Forschung 

Baden-Württemberg 

Helmholtzstraße 8, 89081 Ulm 

Widderstall 

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Li-Ion Batteries Anode Materials (Part 2) - ZSW

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