Na2S-P2S5 glass-ceramic electrolytes for sodium batteries at room temperature

Presented by

*Paramjyot Kumar Jha, O. P. Pandey, K. Singh

*Research ScholarSchool of Physics and Materials ScienceThapar University, Patiala, Punjab, INDIA

ICAER 2013 11/12/2013

Paper Id 239

Outline of presentation

☺ Introduction of Solid Electrolyte

☺ Applications of Solid Electrolyte

☺ Experimental Procedure

☺ Results and Discussion

☺ Conclusions

☺ Acknowledgment

ICAER 2013 11/12/2013

Any substance containing free ions that make

the substance electrically conductive is called

electrolyte.

A solid compound in which ions migrate through

vacancies or interstices within the lattice which

leads to ionic conductivity.

What is electrolyte?

What is Solid electrolyte?

ICAER 2013 11/12/2013

۞ Availability of large number of free ions.

۞ Requirement of low activation energy for the movement

of ions into neighbouring sites.

۞ Three dimensional networking for free movement of the

ions.

۞ The anion framework should be highly polarizable.

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Characteristics of Solid Electrolyte

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Applications of Solid Electrolyte

Gas Sensors

Fuel Cells

Solid State batteries

Advantages of solid state batteries over conventional batteries

Higher ionic conductivities

Isotropic properties

No grain and hence no grain boundaries

Exhibits ionic conductivity in the range of

10-1 to 10-4 S/cm at room temperature.

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Superionic glasses for Solid electrolytes

• 35Na2S-65P2S5 NP1

• 40Na2S-60P2S5 NP2

• 45Na2S-55P2S5 NP3

• 50Na2S-50P2S5 NP4

• 55Na2S-45P2S5 NP5ICAER 2013 11/12/2013

Glass Compositions xNa2S- (100-x)P2S5

Sample preparationby melt quenched technique

Characterization

XRD DTA/TGA DilatometerSEM

Impedance Spectroscopy

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Raman Spectroscopy

METHODOLOGY

at 700 $ C

10 20 30 40 50 60 70 80

35 % Na2S

40 % Na2S

45 % Na2S

55 % Na2S

50 % Na2S

2 (degree)

In

tensity (a.u

)

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X-ray diffraction of glasses

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Dilatometeric study

50 100 150 200 250

0.0

5.0x10-4

1.0x10-3

1.5x10-3

2.0x10-3

Temperature /C

dL/L

0

35 mol% Na2S

40 mol% Na2S

45 mol% Na2S

50 mol% Na2S

55 mol% Na2S

50 100 150 200 250 300

0.0

5.0x10-4

1.0x10-3

1.5x10-3

2.0x10-3

168 C

Temperature /C

dL/L

0

120 C

-1.0x10-5

-5.0x10-6

0.0

5.0x10-6

1.0x10-5

1.5x10-5

d(d

L/L

0)

40 mol % Na2S

50 100 150 200 250 300

0.0

4.0x10-4

8.0x10-4

1.2x10-3

1.6x10-3 45 mol% Na2S

Temperature /C

dL/L

0

-3.0x10-6

0.0

3.0x10-6

6.0x10-6

9.0x10-6

d(d

L/L

0)

185 C

50 100 150 200 250 300

0.0

4.0x10-4

8.0x10-4

1.2x10-3

1.6x10-3

50 mol % Na2S

170 C110 C

-2.0x10-5

-1.5x10-5

-1.0x10-5

-5.0x10-6

0.0

5.0x10-6

1.0x10-5

dL

/L0

Temperature /C

d(d

L/L

0)

50 100 150 200 250 300

0.0

4.0x10-4

8.0x10-4

1.2x10-3

1.6x10-3

55 mol % Na2S

-1.0x10-5

-5.0x10-6

0.0

5.0x10-6

1.0x10-5173 C

Temperature /C

dL/L

0

d(d

L/L

0)

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Differentiation of Dilatometeric curves for Glasses

250 500 750 1000 1250 1500 1750 2000

1279

1164

1011

948

684

620

528

379

300

35 mol % Na2S

40 mol % Na2S

45 mol % Na2S

50 mol % Na2S

55 mol % Na2S

60 mol % Na2S

Inte

nsity (a.u

.)

Raman shift (cm-1)

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Raman Spectroscopy

Mol %(Na2S)

35 40 45 50 55 60 Assignment

Wave numb

er (cm-1)

300 294 300 307 303 343 νas(P-S-P)

379 375 386 382 384 487 stretching vibration of

the P-S bond

528 540 … … … 539 νs(P-S-P)

620 621 … … … 878 νs(POP)

684 690 684 683 683 690 stretching vibrations

of P = S mode

… … … … … 948 SO32- ion

… … … 1011 … 1011 νs(SO42- )

1164 1162 1164 1161 1164 1151 νs(PO2)

1279 1276 1279 1266 1274 1256 νas(PO2)

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Table 1

100 200 300 400 500 600

Tm

Tg

Tc

Endo

Dow

n /E

xo u

p (

V)

Temperature C)

10 C/min 20 C/min 30 C/min 40 C/min

45 mol %

100 200 300 400 500 600 700

Endo

Dow

n /E

xo u

p (

V)

Tg

Tm

Tc1

Tc2

Temperature C)

10 C/min 20 C/min 30 C/min 40 C/min

Tc2

55 mol %

τ.Tg = constant Tg increases means relaxation dynamics in the glass.

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Differential Thermal Analysis (DTA)

1.5 1.6 1.7 1.8 1.9

9.0

9.5

10.0

10.5 Linear fit of Tc Linear fit of Tg

ln

1000/T(K-1)1.5 1.6 1.7 1.8 1.9

8.8

9.2

9.6

10.0

10.4

ln

1000/T(K-1)

Linear fit of Tc Linear fit of Tg

ln [Tc2⁄β] = Ea⁄(RTc ) + constant

Where, Tc is the peak crystallization temperature, R is the gas constant and β is heating

rate. A graph between ln [Tc2⁄β] and 1000/Tc gives straight line and from its slope (Ea/R)

activation energy of the crystallization is obtained. ICAER 2013 11/12/2013

Kissinger plot for Tg and Tc at different heating rates

Glass Heating rate

(⁰C/min.)

Tg (⁰C)

Tc

(⁰C)Tm

(⁰C)∆T =

Tc-Tg (⁰C)Ea

(kJ mol-1)Hr =

(Tc-Tg)/(Tm-Tc)

X = 45 10 276 344 547 68 0.33

20 278 355 552 77 370 (Tg) 0.39

30 283 362 555 79 170 (Tc) 0.40

40 286 370 559 84 0.44

X = 55 10 252 318 616 66 264 (Tg) 0.22

20 257 325 621 68 165 (Tc) 0.22

30 260 338 624 78 0.27

40 264 345 626 81 0.29

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Crystallization Kinetics Parameters

10 20 30 40 50 60 70 80

*

*

*

*

Na3PS

4* Na2S2O3Rest NaPO

3

Inte

nsi

ty (

a.u

.)

(degree)

55 % Na2S

50 % Na2S

45 % Na2S

40 % Na2S

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X-ray diffraction of glass-ceramics

40 45 50 55

2.24

2.28

2.32

2.36

Density (g/c

c)

Mol % Na2S

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Density Variation

1 2 3 4 5h (eV)

(h)2

40 % Na2S

45 % Na2S

50 % Na2S

55 % Na2S

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UV-Visible Spectroscopy of Glass-ceramics

S. No.

Glass compositio

n(Mol %)

Densityρ (g/cc)

Band gap (eV)

Bulk resista

nce(Ω) × 103

Ionic conduct

ivity (S/cm) × 10-5

Volume fractions

Na2S P2S5 NaPO3 Na2S2O3 Na3PS4

1 40 60 2.24 3.60 118.2 0.12 85 7 8

2 45 55 2.29 3.48 72.8 0.18 81 9 10

3 50 50 2.33 3.35 6.11 2.0 74 12 14

4 55 45 2.35 2.99 1.84 6.0 69 16 15

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Table 2

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FE-SEM micrographs of Glass-ceramics

X = 40

X = 50

X = 45

X = 55

• All sample shows halo pattern indicating its amorphous nature.

• Glass samples for x = 45 and x = 55 mol % Na2S shows good

stability.

• Glass-ceramics sample shows mainly three phases.

• With increase in Na2S content the most conducting phase Na3PS4 is

found to be increased.

• The ionic conductivity of present samples are found to be in the

order of 10-5 S/cm at room temperature.

• SEM micrographs reveals dense and well grown crystals. ICAER 2013 11/12/2013

Conclusions

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Acknowledgment

• I would like to thank my Supervisors Dr. Kulvir Singh (Professor &

Head) and Dr. O. P. Pandey (Senior Professor), Thapar University,

Patiala for their Guidance.

• I would like to thank Department of Science and Technology (DST),

New Delhi for the financial support.

• I would like to thank Technical Education Quality Improvement

Programme (TEQIP), Thapar University, Patiala for the travel

support.

• I would like to thank the Organizer (Dr. P. C. Ghosh ) of ICAER who

has given me an opportunity to present my work here.

ICAER 2013 11/12/2013

Thank you for your Kind Attention