Conductivité ionique dans les verresConductivité ionique dans les verres

A. Pradel, A. Piarristeguy, M. Ribes

Institut Charles Gerhardt Montpellier,

Équipe Chalcogénures et Verres,

CC1503, Université Montpellier 2,

Pl. E. Bataillon, F-34095 Montpellier cedex 5, France

Verres contenant des alcalins,

alcalino-terreux ou ions argent

Conduction Ioniqueélevée

Oxydes etChalcogénures

Dispositifs de stockage de l’énergie

Dispositifs de stockage de l’information

Batteries tout-solide

Mémoires ioniques

Spectroscopie d’impédance Complexe

Une succession de signaux de tension sinusoïdale U(ω) de fréquences

différentes est appliquée à l’échantillon

Intensité sinusoïdale I(ω) enregistrée

Impédance du matériau

Circuit modélisant le comportement électrique d’un verre

avec τ = RC (constante de temps)

e = épaisseur de l’échantillon,S = surface métallisée en contact avec l’électrode

Spectroscopie d’impédance Complexe

Diagramme de Nyquist

R= résistance

Conductivité

e = épaisseur de l’échantillon,S = surface métallisée en contact avec l’électrode

Ley de Arrhenius

Eσ : énergie d’activationσo: terme pré-exponentiel

)/exp(0 kTET σσσ −= 0ln

kTE)T.ln( σσ σ +−=

Dépendance avec la température : Loi d’Arrhenius

L’énergie d’activation est déterminée en calculant, par régression linéaire, la pente

de la droite ln(σΤ) = f(1/kT).

30 32 34 36 38 40-7

-6

-5

-4

-3

-2

-1

0

x = 10 x = 15 x = 20 x = 25

ln(σ

T) (S

cm

-1K

)

1 / kT (eV -1)

2.0 2.2 2.4 2.6 2.8 3.0 3.2 3.4

0.33

0.34

0.35

0.36

0.37

0.38

E σ (eV

)

ln(x) ( %at.)

0 4 8 12 16 20 24 280

5000

10000

15000

20000

σ 0 (S c

m-1K)

x (% at.)

Energie d’activation

Spectroscopie d’impédance Complexe : Système Agx(Ge0.25Se0.75)100-x

0 22000 44000 66000 88000 1100000

10000

20000

30000

40000

50000

60000

ω aumenta

x = 15

- Z´´

celd

a( ω

)

Z celda(ω )

294K 298K 303K 313K 323K 333K 343K 353K 363K

Terme pré-exponentiel

M. A. Ureña, A. A Piarristeguy. M. Fontana, B.Arcondo; SSI 176 (2005) 505.A. Piarristeguy, J. M. Conde Garrido, M. A. Ureña,M. Fontana, B. Arcondo; J. Non-Cryst.Sol. 353(2007) 3314.

Ion conducting glasses

(structure locale, 11B RMN, 31P RMN)System : 45 Li2O – 55 [x B2O3 – (1-x) P2O5)]Mixed glass former effect: Oxide glasses

Mixed glass former effect: Chalcogenide glassesSystems : 0.3 Li2S 0.7[(1-x)SiS2 xGeS2], 0.5 Li2S 0.5[(1-x)SiS2 xGeS2] (structure locale, SAXS, Tg)

Ag-based glasses Systems : Agx(Ge0.25Se0.75)100-x, Ag2S-GeS2, Ag2S-GeS-GeS2, Ag2S-As2S3

(separation de phases, EFM, C-AFM)

System : 45 Li2O – 55 [x B2O3 – (1-x) P2O5)]

Ion conducting glasses

Mixed glass former effect: Oxide glasses

Li2O

B2O3P2O5

2. Twin roller quenching

Extension of vitreous domain up to x=1

x=1

600 nm

x=0.64

x=0.64

600 nm

Thèse B. Raguenet

B. Raguenet, G. Tricot, G. Silly, M. Ribes and A. Pradel, Solid State Ionics, 208, 2012, 25-30

Activation energy Activation energy Conductivity Conductivity

Mixed glass former effect: Oxyde glassesSystem : 45 Li2O – 55 [x B2O3 – (1-x) P2O5)]

System 45 Li2O – 55 [x B2O3 – (1-x) P2O5)]: conductivity

B. Raguenet, G. Tricot, G. Silly, M. Ribes and A. Pradel, Solid State Ionics, 208, 2012, 25-30

Glass transition temperature Glass transition temperature

Mixed glass former effect: Oxyde glassesSystem : 45 Li2O – 55 [x B2O3 – (1-x) P2O5)]

System 45 Li2O – 55 [x B2O3 – (1-x) P2O5)]: Tg

B. Raguenet, G. Tricot, G. Silly, M. Ribes and A. Pradel, Solid State Ionics, 208, 2012, 25-30

System 45 Li2O – 55 [x B2O3 – (1-x) P2O5)]: RMN

11B Chemical Shift / ppm-1001020

0.09

0.18

0.27

0.36

0.45

0.55

0.64

0.73

0.82

0.91

1.00

BO4#1

BO4#2

BO3

11B@18.8 T 31P@ 9.4 T

-60-40-2002031P Chemical Shift / ppm

0.09

0.18

0.27

0.36

0.45

0.55

0.64

0.73

0.82

0.91

0.00

Q3

Q2

Q1Q0

G. TricotTGIR Lille

ppm

-520 15 10 5 0 ppm

40

20

0

11B Chemical Shift / ppm

ppm

-520 15 10 5 0 ppm

40

20

0

11B Chemical Shift / ppm

x=0.36 x=0.64

BO3

BO4#1BO3

BO4#211B DQ-SQ @ 18.8 T

System 45 Li2O – 55 [x B2O3 – (1-x) P2O5)]: RMN

B. Raguenet, G. Tricot, G. Silly, M. Ribes and A. Pradel, J. Mat. Chem. 21, 2011, 17693

0.0 0.2 0.4 0.6 0.8 1.0

0

10

20

30

40

50

60

B

O3 &

BO 4

x

BO3

BO4

BO4#1

BO4#2

System 45 Li2O – 55 [x B2O3 – (1-x) P2O5)]: RMN

B. Raguenet, G. Tricot, G. Silly, M. Ribes and A. Pradel, J. Mat. Chem. 21, 2011, 17693

The coordination alone impacts theconductivity!Li+ acts as a charge compensator inthe presence of BO4 units. It is thenmore mobile than Li+ close to nonbridging oxygen

ü The Mixed Network Former Effect is directly related to the BO4units!

0.0 0.2 0.4 0.6 0.8 1.0-10

0

10

20

30

40

50

60

70

BO

4 & B

O3

x

BO3 BO4 log σ

-9.5

-9.0

-8.5

-8.0

-7.5

-7.0

-6.5

-6.0

-5.5

log

σ (S

/cm

)

The decrease in conductivity at highboron content occurs when the ratioBO3/BO4>1. BO3 units probably breakthe conduction paths.

The presence of phosphorous helpsessentially in favouring the existenceof BO4 against BO3

System 45 Li2O – 55 [x B2O3 – (1-x) P2O5)]: RMN

B. Raguenet, G. Tricot, G. Silly, M. Ribes and A. Pradel, J. Mat. Chem. 21, 2011, 17693

System Li2S- [(1-x)SiS2-xGeS2]

Mixed glass former effect: Chalcogenide glasses

0.3 Li2S 0.7[(1-x)SiS2 xGeS2]

0.5 Li2S 0.5[(1-x)SiS2 xGeS2]

V.K. Deshpande, A. Pradel, M. Ribes, Mat. Research Bull., 23(3), 379 (1988)

ConductivityConductivity Activation energy Activation energy

0.0 0.2 0.4 0.6 0.8 1.00.30

0.35

0.40

0.45

0.50

0.5Li2S-0.5[(1-x)SiS2-xGeS2]

0.3Li2S-0.7[(1-x)SiS2-xGeS2]

E σ (e

V)

x

0.0 0.2 0.4 0.6 0.8 1.0

1E-6

1E-5

1E-4

1E-30.5Li2S-0.5[(1-x)SiS2-xGeS2]

x

σ (S

/cm

)

0.3Li2S-0.7[(1-x)SiS2-xGeS2]

System Li2S- [(1-x)SiS2-xGeS2]:: Conductivity and Eσ

Mixed glass former effect: Chalcogenide glasses

V.K. Deshpande, A. Pradel, M. Ribes, Mat. Research Bull., 23(3), 379 (1988)

0.0 0.2 0.4 0.6 0.8 1.0

175

200

225

250

275

300

325

350

375

x

T g ( o C

)

2 Tg and a minimum in ρ for ~50:50 ratio in former content

0.0 0.2 0.4 0.6 0.8 1.0

175

200

225

250

275

300

325

350

375T g (

o C)

x

0.3 Li2S 0.7[(1-x)SiS2 xGeS2] 0.5 Li2S 0.5[(1-x)SiS2 xGeS2]

Smooth change in Tg

0.0 0.2 0.4 0.6 0.8 1.01.9

2.0

2.1

2.2

2.3

2.4

2.5

x

ρ (g

/cm

3 )

System Li2S- [(1-x)SiS2-xGeS2]: Tg and density

Porod Law:aggregates or clusters of

50 Å in size

Debye-Bueche model:homogeneous glasses

System Li2S- [(1-x)SiS2-xGeS2]: SAXS

0.3 Li2S 0.7[(1-x)SiS2 xGeS2]

A. Pradel, Ch. Rau, D. Bittencourt, P. Armand, E. Philippot, M. RibesChemistry of Materials, 10 (8), 2162-2166 (1998).

amorphous

GeS2

amorphous

SiS2

Addition of Li2S

Preferential destruction of edge sharing tetrahedra(29Si NMR investigation)

Different medium range order

No possible mixing of the two formers

Complete phase Separation

(Tenhover 1983)

xLi2S- (1-x)SiS2

x=0.3 different MRO phase separation

x=0.5 similar MROComplete solid solution

System Li2S- [(1-x)SiS2-xGeS2]: Structure

A. Pradel, Ch. Rau, D. Bittencourt, P. Armand, E. Philippot, M. RibesChemistry of Materials, 10 (8), 2162-2166 (1998).

with 0 < x < 30 % at.

Samples

Agx(Ge0.25Se0.75)100-x

0 5 10 15 20 25-13

-12

-8

-7

-6

-5

-4

log

σ (Ω

−1 c

m-1)

% at. Ag

-13

ConductivityConductivity

7-8 orders of magnitude

A sudden break in the

« conductivity vs Ag content »

curve for 8-10% in Ag

Structure / Electrical properties: Ag-Ge-Se(S) systems

M. A. Ureña, A. A Piarristeguy. M. Fontana, B. Arcondo; SSI 176 (2005) 505.A. Piarristeguy, J. M. Conde Garrido, M. A. Ureña, M. Fontana, B. Arcondo;J. Non-Cryst.Sol. 353 (2007) 3314.

EFM V = - 5V

Clear-areas (Ag-poor phase)

FE-SEM

Ag5

Ag15

3μm

3μm Dark-areas (Ag-rich phase)

1.0µm

1.0µm

Ag5

Ag15

Ag5

Dark-areas (Ag-poor phase)

Clear-areas (Ag-rich phase)

Microstructural study : Agx(Ge0.25Se0.75)100-x glasses

UEFMD

dsample

cantilever

A.A. Piarristeguy, M. Ramonda, M.A. Ureña, A. Pradel, M. Ribes, J. Non-Cryst. Solids 353 (2007) 1261-1263.

Ag-rich phaseembedded in Ag-poor phase

Ag-rich phaseis the connecting

phase

Percolation threshold

350nm

Ag1

1.0µm

Ag5

1.0µm

Ag25

1.0µm

Ag20

1.0µm

Ag15

0 5 10 15 20 25-14

-12

-10

-8

-6

-4

-2

log

σ (S

cm

-1 )

at. % Ag

Kawasaki et al. Ureña et al.

& Piarristeguy et al.

Microstructural study: FE-SEM and EFMMicrostructural study : Agx(Ge0.25Se0.75)100-x glasses

V. Balan, A.A. Piarristeguy, M. Ramonda, A. Pradel, M. Ribes, J. Optoelect. and Adv. Material Vol.8 ISS.6 (2006) 2112-2116.

Ag2S-GeS2 (15%Ag)

FE-SEM EFM -3V

Ag2S-GeS-GeS2 (16,7%Ag)

0,01 0,1 1 10 100-16

-14

-12

-10

-8

-6

-4

-2

log

σ (S

/cm

)

%Ag

Ag2S-GeS-GeS2

Ag2S-GeS2

1.0µm

1.0μm

E. Bychkov, V. Tsegelnik, Yu. Vlasov, A. Pradel, M. Ribes, J. Non-Cryst.Solids 208, 1 (1996).A. Pradel, N. Kuwata, M. Ribes, J. Phys.: Condens. Matter 15, 1561(2003).

Microstructural study : Ag-Ge-S glasses

V. Balan, A.A. Piarristeguy, M. Ramonda, A. Pradel, M. Ribes, J. Optoelect. and Adv. Material Vol.8 ISS.6 (2006) 2112-2116.

ü The current through the Ag-rich phase increases when the

applied dc bias increases.

ü Practically any current flows through the Ag-poor phase.

400nm- 0,60 V- 0,80 V

- 0,45 V- 0,90 V- 1,25 V- 0,95 V- 1,15 V

- 0,65 V- 0,85 V- 0,55 V- 0,75 V- 0,45 V- 0,70 V- 0,50 V 400nm- 0,60 V- 0,80 V

- 0,45 V- 0,90 V- 1,25 V- 0,95 V- 1,15 V

- 0,65 V- 0,85 V- 0,55 V- 0,75 V- 0,45 V- 0,70 V- 0,50 V

µm

I (p

A)

I1

I2

V=V1

Ag20(Ge0.25Se0.75)808,17pA

-31,37pA

IA

VDC

Conductivity of each phase: Conductive Atomic Force Microscopy

ü C-AFM

A.A. Piarristeguy, M. Ramonda, N. Frolet, M. Ribes, A. Pradel, Solid State Ionics 181 (2010) 1205-1208.

-4.5 -4.0 -3.5 -3.0 -2.5 -2.0 -1.5 -1.0 -0.5-12

-11

-10

-9

-8

-7

-6

Voltage (V)

Cur

rent

(pA

)

Ag10 Ag15 Ag20

Qualitative evaluation of conductivity

If the contact is assumedto be circular and Ohmic in nature

then the relation between the resistance R and the resistivity ρ is

given by the basic spreadingresistance formula R ~ ρ/4r where r is

the radius of the contact

For the tip radius: : r∼ 10 nm

σ ∼ 0,3 x 10-6 Ω-1cm-1

to 3 x 10-6 Ω-1cm-1

with increasing of the silver content in the samples.

For the tip radius: : r∼ 10 nm

σ ∼ 0,3 x 10-6 Ω-1cm-1

to 3 x 10-6 Ω-1cm-1

with increasing of the silver content in the samples.

Conductivity of each phase: Conductive Atomic Force Microscopy

ü C-AFM

A.A. Piarristeguy, M. Ramonda, N. Frolet, M. Ribes, A. Pradel, Solid State Ionics 181 (2010) 1205-1208.

Conclusion

System : 45 Li2O – 55 [x B2O3 – (1-x) P2O5)]

System : 30 Li2S – 70 [x SiS2 – (1-x) GeS2)]

System : Agx(Ge0.25Se0.75)100-x

Evolution non linéaire de la conductivité liée à la stabilisation des BIV

en présence d’entités phosphate

Augmentation de la conductivité quand Ge/Si ~ 1 due à une séparation de phase

Saut de conductivité de 8 ordres de grandeur due à la percolation d’une phase riche en argent

Rôle important de la structure sur la mobilité des ions dans les verres