In-operando XAS analysis of Li-ion and Li-sulphur batteries Iztok Ar - - PowerPoint PPT Presentation

SLIDE 1

Iztok Arčon

XAS

• 19. 11. 2014

Joint ICTP – IAEA School on novel experimental methodologies fro SR aaplications in nano-science and environmental monitoring

In-operando XAS analysis of Li-ion and Li-sulphur batteries Iztok Arčon 1,2

Robert Dominko 3,4, Giuliana Aquilanti 5, Manu Patel 3,4,Lorenzo Stievano 5

1 University of Nova Gorica, Vipavska 13, POB 301, Nova Gorica, Slovenia 2 J. Stefan Institute, Jamova 39, P. P. 3000, Ljubljana, Slovenia 3 National institute of Chemistry, P.O.B. 660, SI-1001 Ljubljana, Slovenia 4Center of excelence Low carbon technologies, Ljubljana, Slovenia 5 Elettra Sincrotrone Trieste, Italia 6 Univeriste Montpellier II, 2 Place Eugene Bataillon–CC 1502, 34095 Montpellier (France)

SLIDE 2

Iztok Arčon

XAS

• 19. 11. 2014

www.ung.si/~arcon/xas

Motivation for in-operando XAS analysis on Li-ion batteries

• Searching for new cathode materials for high energy Li-ion batteries with

fully reversible lithium extraction that can deliver high battery capacitiy.

• Some candidates Li2VTiO4, Li2FeTiO4 and Li2(FexMnx-1)SiO4
• Exploiting the reversable oxidation potential of Fe2+/Fe3+, Mn2+/Mn3+/ Mn4+

and V2+/V3+/V 4+ redox couples without collapse of the structure.

 Theoretical specific capacity ~ 166 mAh/g

(332 mAh/g if both Li equivalents are extracted);  Thermal stable cathode materials;  Cheap and environmental acceptable cathode materials;

SLIDE 3

Iztok Arčon

XAS

• 19. 11. 2014

www.ung.si/~arcon/xas

Aim of in-operando XAS on Li-ion batteries

• The feasibility and reliability of in situ XANES and EXAFS

analysis as a tool to monitor gradual changes of oxidation state and local structure of transition-metal cations during lithium exchange, i.e. during charging and discharging of the Li-ion battery.

• Provide the information on the dynamics of the battery
• peration on the atomic level and clarify the role of

transition-metal cations (Fe, Mn, V) in the electrochemical activity of the material. Determine the degree of reversibility

• f the process in one or several cycles.
• R. Dominko, I. Arčon, et al., Journal of Power Sources 189 (2009) 51–58

SLIDE 4

Iztok Arčon

XAS

• 19. 11. 2014

www.ung.si/~arcon/xas

Some basic facts about the Li2(Fe0.8Mn0.2)SiO4 meterial

XRD data :

• Monoclinic crystal structure with P121/n1 space
• group. a = 8.245 Å, b = 5.018 Å and c = 8.246 Å
• The structure is composed of MnO4, FeO4,

SiO4 and LiO4 tetrahedra.

• The crystal structure contains empty octahedral

interstitial cavities that form empty channels, which enables transport of Li+ ions.

Moesbauer data on Fe valence in as synthesized Li2Fe0.8Mn0.2SiO4:

• 80% Fe2+ (tetrahedral iron in crystal structure)
• 20% Fe3+ (tetrahedral iron in crystal structure)
• R. Dominko, M. Bele, M. Gaberšček, A. Meden, M. Remškar, and
• J. Jamnik, Electrochem. Commun. 8, 217 (2006).

Advantages:

• high capacity (200 mAh/g at a C/50 cycling rate)
• good thermal stability

0.0 0.2 0.4 0.6 0.8 1.0 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5

U / V vs. Li/Li

+

x in Li2-xFe0.8Mn0.2SiO4

Charge / discharge curves in the first cycle at C/15 current density at 60 oC. Exchanged of 1 mol Li.

SLIDE 5

Iztok Arčon

XAS

• 19. 11. 2014

www.ung.si/~arcon/xas

In operando XAS experiment

• Li2FeTiO4 charging (411min), discharging (192 min) at RT

with C/10 current density in time intervals of 25 min.

• Li2Fe0.8Mn0.2SiO4: In situ charging ( 908 min), discharging (852 min)

at 60 oC with C/15 current density in time intervals of 50 min

• XAFS beamline at ELETTRA and C beamline in HASYLAB at DESY,
• Hamburg. A Si(111) double crystal monochromator with about 1 eV

energy resolution at Fe k-edge (7112 eV) was used. Exact energy calibration with simultaneous absorption measurements on a 5 mm thick V, Fe or Mn metal foil. Absolute energy reproducibility of the measured spectra was 0.05 eV.

In situ battery charge / discharge

6400 6800 7200 7600 8000 0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5

Mn EXAFS Fe EXAFS

Mn K-edge XANES Fe K-edge XANES

d

E (ev)

Half-battery sealed in triplex foil:

Fe and Mn XANES and EXAFS spectra were measured in time intervals of of 55 min.

ELETTRA, XAFS beamline, April 2009

• wen – 60oC

SLIDE 6

Iztok Arčon

XAS

• 19. 11. 2014

www.ung.si/~arcon/xas

Li2-xFe0.8Mn0.2SiO4

battery charging battery discharging

7110 7115 7120 7125 7130 7135 7140 7145 0.0 0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6 end of oxidation (1

st cycle)

86% Fe

3+

as synth. 22% Fe

3+

Fe oxidation Normalised absorption

E (eV)

7110 7115 7120 7125 7130 7135 7140 7145 0.0 0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6

end of reduction (1

st cycle)

27% Fe

3+

start of reduction (1

st cycle)

86% Fe

3+

as synth. 19.5% Fe

3+

Fe reduction Normalised absorption

E (eV)

• R. Dominko et al., Journal of The Electrochemical Society, 157 12 A1309-A1316 2010

SLIDE 7

Iztok Arčon

XAS

• 19. 11. 2014

www.ung.si/~arcon/xas

Li2-xFe0.8Mn0.2SiO4

battery charging

Mn oxidation

battery discharging

Mn reduction

6535 6540 6545 6550 6555 6560 6565 0.0 0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6

end of reduction (1

st cycle)

11% Mn

3+

start of reduction (1

st cycle)

37% Mn

3+

as synth. 100% Mn

2+

Normalised absorption

E (eV)

6535 6540 6545 6550 6555 6560 6565 0.0 0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6

end of oxidation (1

st cycle)

37% Mn

3+

as synth. 100% Mn

2+

Normalised absorption

E (eV)

• R. Dominko et al., Journal of The Electrochemical Society, 157 12 A1309-A1316 2010

SLIDE 8

Iztok Arčon

XAS

• 19. 11. 2014

www.ung.si/~arcon/xas

Li2-xFe0.8Mn0.2SiO4

Linear combination fit

• f XANES spectra of intermediate states with the

spectra of the starting and the most charged state.

7100 7110 7120 7130 7140 7150 1 2 3 4

• dis. 841 min
• ch. 336 min

75% Fe

3+

58% Fe

3+

86% Fe

3+

• ch. 908 min

74% Fe

3+

• dis. 204 min
• ch. 537 min

56% Fe

3+

• dis. 351 min

35% Fe

3+

• dis. 694 min

34% Fe

3+

27% Fe

3+

• ch. 141 min

22% Fe

3+

as-sint.

Li2-xFe0.8Mn0.2SiO4 Normalised absorption

E (eV)

7100 7110 7120 7130 7140 7150 7160 0.0 0.5 1.0 1.5

• ch. 908 min

34% Fe

3+

Li2-xFe0.8Mn0.2SiO4

• ch. 141 min

Li2-xFe0.8Mn0.2SiO4-sint (81%) Li2-xFe0.8Mn0.2SiO4 (19%)

Normalised absorption E (eV)

Experiment Fit

7100 7110 7120 7130 7140 7150 7160 0.0 0.5 1.0 1.5

• ch. 908 min

56% Fe

3+

Li2-xFe0.8Mn0.2SiO4

• ch. 336 min

Li2-xFe0.8Mn0.2SiO4-sint (47%) Li2-xFe0.8Mn0.2SiO4 (53%)

Normalised absorption E (eV)

Experiment Fit

• R. Dominko et al., Journal of The Electrochemical Society, 157 12 A1309-

A1316 2010

SLIDE 9

Iztok Arčon

XAS

• 19. 11. 2014

www.ung.si/~arcon/xas

Li2-xFe0.8Mn0.2SiO4

Linear combination fit

• f XANES spectra of intermediate states with the

spectra of the starting and the most charged state.

7100 7110 7120 7130 7140 7150 1 2 3 4

• dis. 841 min
• ch. 336 min

75% Fe

3+

58% Fe

3+

86% Fe

3+

• ch. 908 min

74% Fe

3+

• dis. 204 min
• ch. 537 min

56% Fe

3+

• dis. 351 min

35% Fe

3+

• dis. 694 min

34% Fe

3+

27% Fe

3+

• ch. 141 min

22% Fe

3+

as-sint.

Li2-xFe0.8Mn0.2SiO4 Normalised absorption

E (eV)

7100 7110 7120 7130 7140 7150 7160 0.0 0.5 1.0 1.5

• ch. 908 min

74% Fe

3+

Li2-xFe0.8Mn0.2SiO4

• dis. 204 min

Li2-xFe0.8Mn0.2SiO4-sint (19%) Li2-xFe0.8Mn0.2SiO4 (81%)

Normalised absorption E (eV)

Experiment Fit

7100 7110 7120 7130 7140 7150 7160 0.0 0.5 1.0 1.5

• ch. 908 min

27% Fe

3+

Li2-xFe0.8Mn0.2SiO4

• dis. 841 min

Li2-xFe0.8Mn0.2SiO4-sint (92%) Li2-xFe0.8Mn0.2SiO4 (8%)

Normalised absorption E (eV)

Experiment Fit

• R. Dominko et al., Journal of The Electroch. Society, 157 12 A1309-A1316 2010

SLIDE 10

Iztok Arčon

XAS

• 19. 11. 2014

www.ung.si/~arcon/xas

Li2-xFe0.8Mn0.2SiO4

Linear combination fit with XANES spectra of “as-sint.” and “ch. 908 min”

7100 7110 7120 7130 7140 7150 1 2 3 4

• dis. 841 min
• ch. 336 min

75% Fe

3+

58% Fe

3+

86% Fe

3+

• ch. 908 min

74% Fe

3+

• dis. 204 min
• ch. 537 min

56% Fe

3+

• dis. 351 min

35% Fe

3+

• dis. 694 min

34% Fe

3+

27% Fe

3+

• ch. 141 min

22% Fe

3+

as-sint.

Li2-xFe0.8Mn0.2SiO4 Normalised absorption

E (eV)

7100 7110 7120 7130 7140 7150 7160 0.0 0.5 1.0 1.5

• ch. 908 min

35% Fe

3+

Li2-xFe0.8Mn0.2SiO4

• dis. 694 min

Li2-xFe0.8Mn0.2SiO4-sint (79%) Li2-xFe0.8Mn0.2SiO4 (21%)

Normalised absorption E (eV)

Experiment Fit

7100 7110 7120 7130 7140 7150 7160 0.0 0.5 1.0 1.5

• dis. 841 min
• ch. 908 min

35% Fe

3+

Li2-xFe0.8Mn0.2SiO4

• dis. 694 min

Li2-xFe0.8Mn0.2SiO4 (86%) Li2-xFe0.8Mn0.2SiO4 (14%)

Normalised absorption E (eV)

Experiment Fit

Linear combination fit with XANES spectra of “dis. 841 min ” and “ch. 908 min”

• R. Dominko et al., Journal of The Electroch. Society, 157 12 A1309-A1316 2010

SLIDE 11

Iztok Arčon

XAS

• 19. 11. 2014

www.ung.si/~arcon/xas

Li2-xFe0.8Mn0.2SiO4

6530 6540 6550 6560 6570 1 2 3 4

Mn

4+

Mn

3+

90% Mn

3+

0% Mn

3+

as-sint

11% Mn

3+

dis 841 min

11% Mn

3+

ch 439 min

14% Mn

3+

dis 449 min

22% Mn

3+

dis 106 min

25% Mn

3+

ch 732 min

37% Mn

3+

ch 908 min Mn-silicate

Mn2O3 MnO MnO2

Normalised absorption (arb. units) E (eV)

Linear combination fit with XANES spectra of “as-sint.” and “ch. 908 min”

6530 6540 6550 6560 6570 6580 0.0 0.5 1.0 1.5

• ch. 908 min

11% Mn

3+

Li2-xFe0.8Mn0.2SiO4

• ch. 439 min

Li2-xFe0.8Mn0.2SiO4 (30%) Li2-xFe0.8Mn0.2SiO4-sint (70%)

Normalised absorption E (eV)

Experiment Fit

6530 6540 6550 6560 6570 6580 0.0 0.5 1.0 1.5

• ch. 908 min

22% Mn

3+

Li2-xFe0.8Mn0.2SiO4

• dis. 106 min

Li2-xFe0.8Mn0.2SiO4 (60%) Li2-xFe0.8Mn0.2SiO4-sint (40%)

Normalised absorption E (eV)

Experiment Fit

• R. Dominko et al., Journal of The Electroch. Society, 157 12 A1309-A1316 2010

SLIDE 12

Iztok Arčon

XAS

www.ung.si/~arcon/xas

Li2-xFe0.8Mn0.2SiO4

6530 6540 6550 6560 6570 1 2 3 4

Mn

4+

Mn

3+

90% Mn

3+

0% Mn

3+

as-sint

11% Mn

3+

dis 841 min

11% Mn

3+

ch 439 min

14% Mn

3+

dis 449 min

22% Mn

3+

dis 106 min

25% Mn

3+

ch 732 min

37% Mn

3+

ch 908 min Mn-silicate

Mn2O3 MnO MnO2

Normalised absorption (arb. units) E (eV)

Linear combination fit with XANES spectra of “as-sint.” and “ch. 908 min”

6530 6540 6550 6560 6570 6580 0.0 0.5 1.0 1.5

• ch. 908 min
• ch. 537 min

25% Mn

3+

Li2-xFe0.8Mn0.2SiO4

• ch. 732 min

Li2-xFe0.8Mn0.2SiO4 (61%) Li2-xFe0.8Mn0.2SiO4 (39%)

Normalised absorption E (eV)

Experiment Fit

6530 6540 6550 6560 6570 6580 0.0 0.5 1.0 1.5

• ch. 908 min

as sinth.

25% Mn

3+

Li2-xFe0.8Mn0.2SiO4

• ch. 732 min

Li2-xFe0.8Mn0.2SiO4 (67%) Li2-xFe0.8Mn0.2SiO4 (33%)

Normalised absorption E (eV)

Experiment Fit

Linear combination fit with XANES spectra of “ch. 537 min ” and “ch. 908 min”

• R. Dominko et al., Journal of The Electroch.

Society, 157 12 A1309-A1316 2010

SLIDE 13

Iztok Arčon

XAS

• 19. 11. 2014

www.ung.si/~arcon/xas

Relative amount of Fe3+ and Mn3+ in Li2-x(Fe0.8Mn0.2)SiO4

during the the proces of battery charging and discharging

300 600 900 1200 1500 1800

10 20 30 40 50 60 70 80 90 100 110

Total valence change (0.8*Fe

3+ + 0.2*Mn 3+)

Mn

3+

Fe

3+

discharging battery charging

(Fe/Mn)3+ (%)

t (min)

• R. Dominko et al., Journal of The Electrochemical Society, 157 12 A1309-A1316 2010

SLIDE 14

Iztok Arčon

XAS

• 19. 11. 2014

www.ung.si/~arcon/xas

EXAFS analysis: model local structure around Mn and Fe cations in Li2(Fe0.8Mn0.2)SiO4

Fe/Mn neigh. Coord. No. Distance R(Å)

O 2 1.99 O 1 2.03 O 1 2.11 Li 1 2.79 O 1 2.92 Li 1 3.04 Si 1 3.05 Li 4 3.10 Si 2 3.13 Li 1 3.16 Si 1 3.18 … … …

The model is based on monoclinic Li2(Fe0.8Mn0.2)SiO4 crystal structure with P121/n1 space

• group. a = 8.245 Å, b = 5.018 Å and c = 8.246 Å obtained by powder XRD.

The structure is composed of MnO4, FeO4, SiO4 and LiO4 tetrahedra. R. Dominko, M. Bele, M. Gaberšček, A. Meden, M. Remškar, and J. Jamnik, Electrochem. Commun. 8, 217 (2006).

Li1 O3 Li Li1 O3 O3 Li1 Li O3 Li1 Li1 O3 Li Li1 O3 O3 Li1 Li Si O1 O3 Li1 Si1 Si Mn1 O1 Mn Mn1 Si Mn O1 O2 Si1 Si O1 O2 O2 O2 Mn1 Mn O2 O1 Mn1 Si1 Si O2 O1 Si1 Mn1 Mn Li O3 Mn1 Li1 Li O3 Li O3 Li1 Li Li O3 O3 Li1 Li O3 Li O3 Li1 Li O3 Li1 O3 Li Li1 O3 O3 Li1 Li O3 Li1 Li1 O3 Li Li1 O3 O3 Li1 Li Si O1 O3 Li1 Si1 Si Mn1 O1 Mn Mn1 Si Mn O1 O2 Si1 Si O1 O2 O2 O2 Mn1 Mn O2 O1 Mn1 Si1 Si O2 O1 Si1 Mn1 Mn Li O3 Mn1 Li1 Li O3 Li O3 Li1 Li Li O3 O3 Li1 Li O3 Li O3 Li1 Li O3

a b c

SLIDE 15

Iztok Arčon

XAS

• 19. 11. 2014

www.ung.si/~arcon/xas

Experiment – (solid line); EXAFS model – (red dashed line)

In operando Fe EXAFS spectra of Li2-xFe0.8Mn0.2SiO4

Changes of Fe local structure during charge/discharge process:

• modifications of FeO4 tetrahedra
• increase of disorder in the second coordination shell (Si)

as synthesized

22% Fe3+

1 O at 1.94 Å 3 O at 2.03 Å σ2

Fe-Si = 0.009 Å2

reduced

27 % Fe3+

4 O at 1.99 Å σ2

Fe-Si = 0.008 Å2

Oxidized

86% Fe3+

4 O at 1.88 Å σ2

Fe-Si = 0.022 Å2

1 2 3 4 5 6 5 10 15 20

• dis. 841 min, 27% Fe

3+

• ch. 908 min, 86% Fe

3+

• dis. 204 min, 74% Fe

3+

• dis. 351 min, 58% Fe

3+

• ch. 336 min, 56% Fe

3+

• ch. 141 min, 34% Fe

3+

as synth. 22% Fe

3+

FT magnitude (arb. units)

R (Å)

4 O O, Si, Li, O

• R. Dominko et al., Journal of The Electroch. Society, 157 12 A1309 (2010)

SLIDE 16

Iztok Arčon

XAS

• 19. 11. 2014

www.ung.si/~arcon/xas

1 2 3 4 5 6 5 10 15 20

• dis. 841 min, 11% Mn

3+

• ch. 908 min, 37% Mn

3+

• ch. 732 min, 25% Mn

3+

• dis. 106 min, 22% Mn

3+

• dis. 400 min, 15% Mn

3+

• ch. 439 min, 11% Mn

3+

as synth. 0% Mn

3+

FT magnitude (arb. units)

R (Å)

Experiment – (solid line); EXAFS model – (red dashed line)

In operando Mn EXAFS spectra of Li2-xFe0.8Mn0.2SiO4

Changes of Mn local structure during charge/discharge process:

• modifications of MnO4 tetrahedra
• increase of disorder in the second coordination shell (Si)

as synthesized

0% Mn3+

3 O at 2.04 Å 1 O at 2.21 Å σ2

Mn-Si = 0.007 Å2

reduced

11 % Mn3+

3 O at 2.04 Å 1 O at 2.17 Å σ2

Mn-Si = 0.008 Å2

Oxidized

37% Mn3+

1 O at 1.85 Å 3 O at 2.05 Å σ2

Mn-Si = 0.016 Å2

4 O O, Si, Li, O

• R. Dominko et al., Journal of The Electrochemical Society, 157 12 A1309-A1316 2010

SLIDE 17

Iztok Arčon

XAS

In operando XANES and EXAFS analysis of Li2-xNiTiO4 cathode materials for Li-ion batteries

• 19. 11. 2014

www.ung.si/~arcon/xas

8330 8335 8340 8345 8350 8355 8360 8365 8370 0.0 0.4 0.8 1.2 1.6 Ni K-edge shift

end of oxidation 63% Ni3+ as preared 17% Ni3+

Ni oxidation Normalised absorption

E (eV)

8330 8335 8340 8345 8350 8355 8360 8365 8370 0.0 0.4 0.8 1.2 1.6

as preared 17% Ni3+ end of oxidation 63% Ni3+

end of reduction 17% Ni

3+

Ni reduction Normalised absorption

E (eV)

I.Arčon, M.Küzma, R. Dominko, M.Gaberšček, In situ XANES and EXAFS analysis of Li2NiTiO4 cathode materials for Li- ion batteries, EXRS2012 confernce presentation, June 18 – 23, 2012

SLIDE 18

Iztok Arčon

XAS

In operando XANES analysis of Li2-xNiTiO4 cathode materials for Li-ion batteries

• 19. 11. 2014

www.ung.si/~arcon/xas 300 600 900

5 10 15 20 25 30 35 40 45

178 min reduction 230 min

• xidation

reduction

• xidation

Ni

3+(%)

t (min)

8320 8330 8340 8350 8360 8370 8380 0.0 0.5 1.0 1.5

Li2-xNiTiO4 (30%)

• ch. 500 min

Li2-xNiTiO4

• ch. 60 min

Li2NiTiO4 (70%) as prepared

Normalised absorption E (eV)

Experiment Fit

8320 8330 8340 8350 8360 8370 8380 0.0 0.5 1.0 1.5

Li2-xNiTiO4 (52%)

• ch. 500 min

Li2-xNiTiO4

• disch. 69 min

Li2NiTiO4 (48%) as prepared

Normalised absorption E (eV)

Experiment Fit

I.Arčon, M.Küzma, R. Dominko, M.Gaberšček, In situ XANES and EXAFS analysis of Li2NiTiO4 cathode materials for Li-ion batteries, EXRS2012 confernce presentation, June 18 – 23, 2012

SLIDE 19

Iztok Arčon

XAS

In operando EXAFS analysis of Li2-xNiTiO4 cathode materials for Li-ion batteries

• 19. 11. 2014

www.ung.si/~arcon/xas

1 2 3 4 5 10 20 30 40 50

Ni, Ti, Li neigh. Oxygen neigh.

• red. 535 min
• red. 178 min
• red. 69 min
• x. 90 min
• x. 261 min
• x. 500 min

as prepared

FT magnitude (arb. units)

R (Å)

The EXAFS spectra were modeled with an ab initio FEFF model based on the crystallographic data of Li2NiTiO4 with rock salt structure. In this structure Ni atoms are located at the centers of

• xygen octahedra with Ni-O distance of 2.074 Å. The

second coordination sphere at the distance of 2.933 Å is occupied randomly by six Li, three Ni and three Ti atoms, followed by more distant coordination shell of eight O atoms at 3.59 Å. The structural changes during oxidation/reduction are limited to the nearest oxygen coordination shell. There are no significant changes of local structure in more distant coordination spheres.

I.Arčon, M.Küzma, R. Dominko, M.Gaberšček, In situ XANES and EXAFS analysis of Li2NiTiO4 cathode materials for Li-ion batteries, EXRS2012 confernce presentation, June 18 – 23, 2012

SLIDE 20

Iztok Arčon

XAS

• 19. 11. 2014

www.ung.si/~arcon/xas

Li2-xVTiO4

rock-salt crystal structure

Linear combination fit

• f V XANES spectra of intermediate states with the

spectra of the starting and the most charged state.

5460 5480 5500 5520 5540 0.0 0.5 1.0 1.5

Li2-xVTiO4

• ch. 64 min

Li2-xVTiO4- as sint (38.8%) Li2-xVTiO4 (61.2%) - ch 501 min

Normalised absorption E (eV)

Experiment Fit

5460 5480 5500 5520 5540 0.0 0.5 1.0 1.5

Li2-xVTiO4

• dis. 170 min

Li2-xVTiO4- as sint (76.0%) Li2-xVTiO4 (24.0%) - ch 501 min

Normalised absorption E (eV)

Experiment Fit

• R. Dominko, et al., J. Power Sources (2010), doi:10.1016/j.jpowsour.2010.09.004

SLIDE 21

Iztok Arčon

XAS

• 19. 11. 2014

www.ung.si/~arcon/xas

Na3-xV2(PO4 )

• R. Dominko, et al., J. Power Sources (2010), doi:10.1016/j.jpowsour.2010.09.004

5465 5470 5475 5480 5485 5490 5495 5500 0.0 0.5 1.0 1.5

end of oxidation Na3V2(PO4)3 Normalised absorption E(eV) V oxidation as sint.

5465 5470 5475 5480 5485 5490 5495 5500 0.0 0.5 1.0 1.5

end of oxidation, start of reduction Na3V2(PO4)3 Normalised absorption E(eV) V reduction as sint., end of reduction

5460 5480 5500 5520 5540 0.0 0.5 1.0 1.5

Li3-xV(PO4 )3 ox. 533 min (40.7%) Na3-xV(PO4 )3 as sint. (59.3%)

Na3-xV(PO4 )3

• x. 216 min

Normalised absorption E (eV)

Experiment Fit

Linear combination fit

• f V XANES spectra of

intermediate states with the spectra of the starting and the most charged state.

SLIDE 22

Iztok Arčon

XAS

• 19. 11. 2014

www.ung.si/~arcon/xas

Na3-xV2(PO4 ) and Li3-xV2(PO4 )

• M. Pivko, I. Arčon et al., Journal of Power Sources 216 (2012) 145-151

5460 5480 5500 5520 5540 0.0 0.5 1.0 1.5

Li3-xV(PO4 )3 ox. 533 min (40.7%) Na3-xV(PO4 )3 as sint. (59.3%)

Na3-xV(PO4 )3

• x. 216 min

Normalised absorption E (eV)

Experiment Fit

Linear combination fit

• f V XANES spectra of

intermediate states with the spectra of the starting and the most charged state.

5460 5480 5500 5520 5540 0.0 0.5 1.0 1.5

Li3-xV(PO4 )3 ox. 521 min (41%) Li3-xV(PO4 )3 as sint. (59%)

Li3-xV(PO4 )3

• x. 205 min

Normalised absorption E (eV)

Experiment Fit

SLIDE 23

Advanced European lithium sulphur cells for automotive applications www.eurolis.eu

Collaborative project FP7-2012-GC-MATERIALS Eleven European partners Sponsored by the European commission Started in 2012 Project coordinator: Robert Dominko National Institute of Chemistry, Slovenia

Li-S batteries are most promising solution for automotive applications Properties:

• high energy density
• small size, low weight,
• safe and a reliable operation,
• environmental friendly,
• cost effective.

Key points:

• Understand the mechanisms of operation, nano-

structuration and electrochemical processes in the cathode material and in the electrolyte during battery

• peration.
• Design new Li-S cathode materials with superior

properties.

Not yet successfully commercialized: Li-S cell technology has to be developed and optimized.

SLIDE 24

Lithium sulphur cell

Resarch, development & engineering: a. Cathode composite

• Host matrix
• Sulphur deposition
• binder

b. Electrolyte

• Solvent(s)
• Salt(s)
• Polymers
• Ionic liquids

c. Separator d. Additives

SLIDE 25

Form ation of polysulphides

Lithium metal Electrolyte and separator Cathode (sulphur)

SLIDE 26

Iztok Arčon

XAS

• 19. 11. 2014

www.ung.si/~arcon/xas

Aim of in-operandoXAS study of Li-S battery

The feasibility and reliability of sulphur K-edge XANES and EXAFS analysis of Li-S batteries in operando as a tool for:

• characterization of the redox chemistry during charging and

discharging of the battery.

• information on changes in the molecular structure of

sulphur and sulphur oxidation state in the cathode material.

• monitoring polysulfide formation to understand the

interactions of sulfur and polysulfides with a host matrix and electrolyte. This information is esential for the development of long cycle life

• f lithium sulfur (Li-S) batteries.

SLIDE 27

EC project EUROLIS (314515)

Experimental: setup

XAFS beamline at Elettra

Sulphur K‐edge (2472 eV)

Fluorescence detection mode ((E) IF/I0)

Samples in vacuum

• r helium atmosphere

Vacuum chamber designed by Nicola Novello (Elettra)

SLIDE 28

In operando XAS measurements

28

Modified 4 -electrode Sw agelok cell

for in operando XAS measurenets with 13 micron Be window

SLIDE 29

Iztok Arčon

XAS

In operando „coffee bag“ cells for XAS spectroscopy

Mylar window External Circut connection Coffee bag or Plastic bag Lithium Foil (Anode) Cathode Electrode Separator Cell after assembling

Lithium polysulfides dissolved in electrolyte.

Li-S battery

SLIDE 30

Change in colors depending on the length of polysulfides

479nm 494nm 513nm 567nm 572nm 536nm 555nm

Chemically synthesized Li2Sx dissoveld in 1M LiTFSI TMS electrolyte

Reference: different polysulfides

30

SLIDE 31

In operando XAS measurements at XAFS beamline (ELETTRA)

SLIDE 32

In operando XAS measurements at XAFS beamline (ELETTRA)

SLIDE 33

2465 2470 2475 2480 2485 0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0

5% S in BN 5% S in CB 10% S in CB

SA corrected

15% S in CB

Normalized absorption (arb. units)

E (eV)

S K‐edge XAS in fluorescence detection mode

Sulfur K edge XANES spectra measured on samples with different concentrations of sulfur in carbon black

• r boron nitride before and after (SA) correction.

Self‐absorption (SA) effect in fluorescence detection mode.

2400 2600 2800 3000 3200 0,0 0,5 1,0 1,5 2,0 2,5 3,0 3,5

Li2S3 in BN

Normalised fluorescence signal

E / eV

Sulfur K edge fluorescence XAS spectrum measured

• n Li2S3 in carbon black normalised to unit K edge

jump

Effect of strong energy dependent penetration depth in fluorescence detection mode.

• M. Patel, I. Arčon et al., ChemPhysChem 2014, 15, 894 – 904

SLIDE 34

2 4 6 8 10 12 14

• 4
• 2

2 4 1 2 3 4 1 2 3 k

2 (k) (Ang.

• 2)

k (Ang.

• 1)

sulfur (tansmission mode) sulfur 5 wt% in CB (fluorescence mode) R (Ang.) |FT| (Ang.

• 3)

S K‐edge EXAFS data normalization – fluorescence detection mode

R = 2.04(1) Ang. CN = 2 2 =0.0034(6) Ang.2 R = 2.03(1) Ang. CN = 2

2 = -0.0028(5) Ang.2

2200 2400 2600 2800 3000 3200 1 2 3 4 5

Absorption Energy (eV) mu-pre/post

2 4 6 8 10 12 14 1 2 3 4 1 k

2 (k) (Ang.

• 2)

k (Ang.

• 1)

sulfur (tansmission mode) sulfur 5 wt% in CB (fluorescence mode) R (Ang.) |FT| (Ang.

• 3)

R = 2.03(1) Ang. CN = 2

2 = 0.0031(5) Ang.2

34

2400 2600 2800 3000 3200 0,0 0,5 1,0 1,5 2,0 2,5 3,0 3,5

Li2S3 in BN Normalised fluorescence signal

E / eV

Uncorrected

• fl. spectrum

Corrected

• fl. spectrum

SLIDE 35

S K-edge XANES of reference com pounds

2465 2470 2475 2480

Na2S8 Na2S6 Na2S4 Na2S3 Na2S2 S Li2S8 Li2S3 Li2S2 Li2S

Li2Sx and Na2Sx in CB, S XANES

Normalized absorption (arb. units) E (eV)

Sulphur, polysulphides, electrolyte

2465 2470 2475 2480 2485

Li2Sx Normalized absorption E / eV electrolyte sulfur Li2S

Li2S8 : Li—S‐S‐S‐S‐S‐S‐S‐S—Li Li2S3 : Li—S‐S‐S—Li Li2S2 : Li—S‐S—Li Li2S : Li—S—Li

Electrolyte LiTFSI in TMS:

• M. Patel, I. Arčon et al., ChemPhysChem 2014, 15, 894 – 904

SLIDE 36

Theoretical calculations

First-principles simulation of the sulfur K-edge XAS spectra of Li2Sx dissolved in TEGDME (x = 2−8) and crystaline Li2S, obtained from XCH-DFT calculations.

• T. A. Pascal et al., J. Phys. Chem. Lett. 2014, 5, 1547−1551

SLIDE 37

Iztok Arčon

XAS

S K-edge XANES of as-prepared battery

• 19. 11. 2014

www.ung.si/~arcon/xas

2460 2470 2480 2490 2500 2510 0,0 0,5 1,0 1,5

Sulphur in CB

Li-S battery at the initial state

TMS+LiTFSI in BN Normalised absorption E (eV)

Experiment Fit Cathode composition: sulphur 20 wt.% 61.5% carbon black (Prx), 3.5% zeolite, and 15%Teflone. (density 1.2 g/cm3) Electrolyte: 1M LiTFSI v TMS 1 M LiTFSI in TMS TMS: Tetra methylene sulfone

• M. Patel, I. Arčon, et al, ChemPhysChem 2014, 15, 894 – 904

SLIDE 38

Iztok Arčon

XAS

In operando S K-edge XANES eksperiment

2460 2470 2480 2490

LiS bat ch. TMS_TFSI LiS bat init.

LiS bat 733 m

Normalized absorption (arb. units) E (eV)

Discharging C/20, charging C/10 Cathode composition: sulphur 20 wt.% in carbon black, Electrolyte: 1M LiTFSI v TMS

Initial state Final state

• M. Patel, I. Arčon, et al, ChemPhysChem 2014, 15, 894 – 904

SLIDE 39

Iztok Arčon

XAS

2460 2470 2480 2490 2500 2510 0.0 0.5 1.0 1.5

sulphur (1%) Li2S (8%) Li2S4 (4%)

charge 130 min

electrolyte (87%)

Normalised absorption E (eV)

Experiment Fit

2460 2470 2480 2490 2 4

e n d

• f

f i r s t c y c l e

charge

Normalized absorption Energy / eV

discharge

i n i t i a l s t a t e

In operando S K-edge XANES eksperiment

Discharging C/20, charging C/20 S K-edge XANES and EXAFS spectra continuously measured (65 min per spectrum)

Intermediate states

2460 2470 2480 2490 2500 2510 0.0 0.5 1.0 1.5

sulphur (2%) Li2S (0%) Li2S4 (10%)

discharge 325 min

electrolyte (88%)

Normalised absorption E (eV)

Experiment Fit

• M. Patel, I. Arčon, et al, ChemPhysChem 2014, 15, 894 – 904

SLIDE 40

I n opearndo XAS m easurem ent

Relative amount of different sulphur compounds in the cathode vs. electrolyte during 1st cycle ob battery opeartion

300 600 900 1200 1500 1800

5 10 15 20 25 70 80 90 100

EC curve

Electrolyte Li2S Li2S4

(%)

t (min) Sulphur

1.4 1.6 1.8 2.0 2.2 2.4 2.6 2.8 3.0

2460 2470 2480 2490 2 4

e n d

• f

f i r s t c y c l e

charge

Normalized absorption Energy / eV

discharge

i n i t i a l s t a t e

• M. Patel, I. Arčon, et al, ChemPhysChem 2014, 15, 894 – 904

SLIDE 41

Post-m ortem S K-edge XANES

0,00 0,25 0,50 0,75 1,00 1,25 1,50 1,75 2,00 1,50 1,75 2,00 2,25 2,50 2,75 3,00

E B U / V vs. Li/Li

+

x in Li

xS

A D C c)

2465 2470 2475 2480 2485 2490 2495 2500

2 468 2470 24 72 2474 247 6 N

• rmalized a bsorption

E / eV

I (S8) A (Li0.28S) B (Li0.85S) C(Li1.90S) D (Li1.00S) E (Li0.17S) Normalized absorption E / eV a)

2465 2470 2475 2480 2485 2490 2495 2500

246 8 24 70 2 472 2 47 4 247 6

Li2Sx

N o rm a l iz e d a b so rp ti o n E / eV

sulfur

I (S8) A (Li0.28S) B (Li0.85S) C(Li1.90S) D (Li1.00S) E (Li0.17S) Normalized absorption E / eV b)

5 different batteries were galvanostatically charged to the characteristic points, stopped, transferred into glove box, opened, and the cathode and the separator were separately sealed into pouched cells with Mylar windows

2460 2470 2480 2490 2500 2510

point E charge at 1.5V

sulphur (16%) electrolyte (84%)

Normalised absorption E (eV) Experiment Fit

c)

2460 2470 2480 2490 2500 2510

point D charge at 2.25V

Li2S (4%) Li2S4 (8%) electrolyte (88%)

Normalised absorption E (eV)

Experiment Fit

b)

2460 2470 2480 2490 2500 2510

point C discharge at 1.5V

Li2S (24%) Li2S3 (15%) electrolyte (61%)

Normalised absorption E (eV) Experiment Fit

a)

• M. Patel, I. Arčon, et al, ChemPhysChem 2014, 15, 894 – 904

SLIDE 42

EC project EUROLIS (314515)

Li polysulphides: S K‐edge EXAFS

From the literature: S‐S bond length: 2.045 Ang. S‐Li bond length: 2.5 Ang

5 10 15

• 0.4
• 0.2

0.0 0.2 0.4 2 4 0.0 0.2 0.4 0.6 0.8 k

2 (k) (Ang.

• 2)

k (Ang.

• 1)

S-S at 2.05 Ang S-Li at 2.5 Ang

|FT| (Ang.

• 3)

R (Ang.) 5 10 15

• 1

1 2 4

0.0 0.2 0.4

k

2 (k) Ang.

• 2

k (Ang.

• 1)

sulfur Li2S8 Li2S3 Li2S2

|FT| (Ang

• 3)

R (Ang.)

2 4 0.00 0.05 0.10 0.15 0.20 |FT| (Ang.

• 3)

R (Ang.) sulfur Li2S8 Li2S3 Li2S2

42

SLIDE 43

EC project EUROLIS (314515)

First large scale Li‐S cells produced at SAFT

First large scale Li-S cells produced at SAFT in May 2014, with the composition developed within EUROLIS project.

SLIDE 44

Iztok Arčon

XAS

www.ung.si/~arcon/xas

Acknowledgements

This work was supported by:

• Slovenian Research Agency
• ELETTRA provided access to their

synchrotron radiation facilities

Coworkers on the XAS experimnets:

 Iztok Arčon (University of Nova Gorica)  Robert Dominko (Inst. Of Chemistry, Lj.)  Manu Patel (Inst. Of Chemistry, Lj.)  Lorenzo Stievano (Université Montpellier II)  Luca Olivi (ELETTRA)  Giuliana Aquilanti (ELETTRA)  Antonella Iadecola (ELETTRA)  Nicola Novello (ELETTRA) …

ELETTRA, XAFS beamline, June 2013 ELETTRA, May 2014

EC project EUROLIS (314515) FP7-2012-GC-MATERIALS