Electrochemical

Supercapacitors in

F.E.E.Lab

Keryn Lian

Department of Materials Science and Engineering

University of Toronto

Keryn.lian@utoronto.ca

416-978-8631

Supercapacitors and Applications

エネルギーストレージシステム

1E+00

1E+01

1E+02

1E+03

1E+04

1E+05

1E+06

0.01 0.1 1 10 100 1000

Energy Density (Wh/kg)

Po

wer

Den

sit

y (

W/k

g)

Ultracapacitors

Capacitors

Batteries Fuel cells

Electrodes

Electrolyte/

separator

2 John R. Miller and Andrew F. Burke, The Electrochemical Society Interface. Spring 2008.

From Prof. K. Noai US DOE workshop

From Maxwell Web

1. Modification of Carbon electrodes

1. Activated Carbon, CNT, graphite nano-fibers and onion-like carbon characterization and chemical modification (Prof. Gogotsi, Drexel )

2. Direct formation of TiNx

Efforts on Electrochemical Capacitor (EC)

2. Solid Polymer

Electrolytes

1. Solid proton

conducting

electrolytes for thin,

flexible devices

2. Ionic liquid/polymer

for high voltage

window.

3. Hybrid Device &System

1. Super thin and flexible symmetrical and asymmetrical EC cells

2. ANN battery and hybrid cycle life prediction (Prof. Weigert, MST)

3. Simulation of devices life and thermal properties (Prof. Dawson, ECE, UT)

4. Hybrid EC with battery, photovoltaic for “self-power” and for extending power/energy efficiency (Prof. Kherani, ECE, UT).

Load

Solar Cell

Battery Electrochemical

Capacitor

(EC)

3

Lian – 2013

4

New Advances in Proton Conducting Polymer

Electrolytes and their Applications in Ultrahigh

Rate Solid Electrochemical Capacitors

Keryn Lian

Department of Materials Science and Engineering

University of Toronto

Keryn.lian@utoronto.ca

416-978-8631

5

Outline

• Background – Ultra-high-rate Solid Electrochemical Capacitors (EC)

– Heteropolyacid (HPA) as proton conducting electrolytes

• Solid Proton Conducting Polymer Electrolytes

• Solid symmetric ECs – Metallic ECs

– Double Layer ECs

– Pseudocapacitve ECs

• Expansion of Cell Voltage – Alternative Electrolytes

– Asymmetric

– Multicell-in-one package

• Summary

• Key words: high rate, solid/flexible

Lian – 2013

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6

Fast device response, small time constant, high power density

0.9 mF/cm2

Onion-like carbon 1

Et4NBF4/propylene carbonate

Graphene nanosheets 2

KOH

90 µF/cm2 (120 Hz)

Reduced graphene oxide 3

H3PO4

0.3 mF/cm2

1. D. Pech, et.al, Nature Nanotechnology 5 (2010) 651

2. J.R. Miller, et.al, Science 329 (2010) 1637.

3. K. Sheng, et.al Scientific Reports 2 (2012).

4. M.F. El-Kady, et.al., Science 335 (2012) 1326.

Laser scribed graphene 4

KOH

1.5 mF/cm2 (10V/s)

Advanced electrodes

Liquid electrolytes

Our goal

Flexible/rollable

EC devices

State-of-the-Art High Rate ECs

?

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7

Battery –Capacitor Hybrid System

– The thin and flexible ultracapacitor can have various form factor

– It can be readily combined with the energy sources

Vo

ltag

e (

V)

2.5 A Pulse, Peak Power > 2.25 W

0.9

1

1.1

1.2

1.3

1.4

1.5

0 20 40 60 80 100

time (min)

EC+Battery hybrid

Battery

only

0.9

1

1.1

1.2

1.3

1.4

1.5

0 10 20 30 40 50

time (min)

EC+Battery hybrid

Battery

only

3.6 A Pulse, Peak Power > 3.4 W

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8

Solid State ECs – polymer electrolytes

To eliminate metal cans and separators to form

flexible dry ECC

Current

Liquid Electrolyte

“SOLID” ELECTROLYTE

“SOLID” ELECTROLYTE

BiPOLAR ELECTRODE

ELECTRODE

ELECTRODE

multicell in one package

polymer electrolyte

Polymer Electrolyte

9

Solid Electrochemical Capacitors

M. El-Kady, et al. Science, 335, 1326 (2012)

Yuan et.al, ACS Nano 6(1) 656 (2012)

K. Lian et.al. US Patent, 5,587,872, (1996)

RuO2 based solid 10-cell EC

10 V/s

Polymer Electrolytes:

PVA-H3PO4

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10

Heteropolyacid (HPA)

• High ionic conductivity at solid state

• Low cost

• Less aggressive chemistry

• Have been considered in fuel cells and sensors

H3PW12O40.29H2O H3PMo12O40.29H2O H4SiW12O40.28H2O

Proton con-

ductivity (S/cm) 0.17 0.18 0.027

0 0.25 0.50-0.10

-0.05

0

0.05

0.10

E (V) vs. Ag/AgCl

I (A

*cm

-2)

1. Bare MWCNT2. Single PMo12

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11

Voltage Operation Window of HPA

*Altenau et.al, Inorg. Chem ., 14, 417, (1975)

Dependence of the 1st one - e- reduction

pontntials on the negative charge: 1)

XW12O40n- and 2) XV12O40

n-

-0.5 0 0.5 1.0 -0.075

-0.050

-0.025

0

0.025

0.050

E (V) vs. Ag/AgCl I

(Am

ps/c

m

2 )

SITA-GRAPHITE-ELECTRODE(-02-1)_Cy04.cor H2SO4-GRAPHITE-ELECTRODE(13)_Cy04.cor PTA-GRAPHITE-ELECTROD(-02-1)E_Cy04.cor

H2SO4

SiWA

PWA

Lian et al. Electrochem. Solid-State Letters, 11(9) A158 2008

Lian - 2013

12

Graphite cell with H2SO4, PWA and SiWA (EDLC)

0 0.25 0.50 0.75 1.00 -0.002

-0.001

0

0.001

0.002

E (V)

I (A

mp

s/c

m2)

GRAPHITE CELL-H2SO4

GRAPHITE CELL-PWA

GRAPHITE CELL-SIWA

0.3 M solution; Sweep Rate = 100 mV/s

0 0.25 0.50 0.75 1.00 -0.010

-0.005

0

0.005

0.010

0.015

E (V)

I (A

mp

s/c

m2)

RuO2 CELL-H2SO4 RuO2 CELL-PWA RuO2 CELL-SiWA

Lian et al. Electrochemical and Solid-State Letters, 11(9) A158 (2008)

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13

Issues and Approaches

Issues of HPAs:

• Poor film forming – Often, HPA are pressed as pellets

• Soluble in water

• Sensitive to moisture and temperature

A good solid electrolyte should possess: High ionic conductivity at all temperature range

High stability and shelf life

Our Approach:

• Composite with polymer to immobilize the HPAs

• Additives

14

Composition of Polymer Electrolytes

Polymer matrix:

Polyvinyl alcohol

(PVA)

Additives:

Glutaraldehyde

Silica oxide

Phosphoric acid

Our polymer electrolytes are comprised of 3 functional

components:

Ionic conductor:

Heteropoly acid

Silicotungstic acid

H4SiW12O40.28H2O (SiWA)

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15

•Lower HPA sensitivity on environment

•Form thin film electrolyte

•Achieve better electrode/electrolyte contact

HPA - Polymer Systems

HPA + additives + Polyvinyl alcohol (>90 wt.%) (<10 wt.%)

Gen I • SiWA + PVA

Gen II • SiWA + H3PO4 + PVA

Gen III • SiWA + H3PO4 + Crosslinked-PVA

(XL-PVA)

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Cell Assembly

Electrolyte thickness ≈50 μm

Electrolyte coating

Hot-pressing 90 oC

Film lamination

Electrode (Stainless steel foils or RuO2 on Ti foils)

PVA-SiWA-H3PO4

Electrode area 0.8 cm2 Cell thickness ≈ 0.2 mm

Pressure and

temperature

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Proton Conductivity of

the Polymer Electrolytes

Stainless Electrodes

17

18

Conductivity of Polymer Electrolytes

•Stainless steel electrodes

•Measured in ambient condition

0 10 20 30 40 50 60 70

0.000

0.005

0.010

0.015

0.020

0.025

0.030

0.035

Gen III (SiWA-H3PO

4-XL-PVA)

Gen II (SiWA-H3PO

4-PVA)

Con

du

ctiv

ity (

S c

m-1

)

Day

Gen I (SiWA-PVA)

SiWA

SS

Poly electrolyte

SS

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3.0 3.1 3.2 3.3 3.4 3.5 3.6 3.7 3.8-5.0

-4.8

-4.6

-4.4

-4.2

-4.0

-3.8

-3.6

-3.4

-3.2

-3.0

-2.8

-2.6

R2=0.98

No cross-linking

Cross-linked (solid polymer)ln

(co

nd

ucti

vit

y)

(Scm

-1)

1000/T (K-1)

R2=0.98

0 oC to 50 oC at 50% RH

9.2 kJ/mol

14.8 kJ/mol

Proton hopping in crystalline material

Arrhenius plot

H. Gao, K. Lian, Journal of Materials Chemistry, 22 (2012) 21272.

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Conductivity and Stability (Comparison with Nafion)

0 2 4 6 8 10 12 14 16

0.000

0.005

0.010

0.015

0.020

0.025

Conduct

ivit

y (

S c

m-1

)

Days

SiWA-H3PO

4-PVA cell

Nafion cell

SS

Poly electrolyte

SS

H. Gao, H. Wu, K. Lian, Electrochem. Commun., Vol 12, p48 (2012)

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Structural Analyses (XRD) (cont)

21

10 20 30 40 50

Inte

nsi

ty (

a.u

.)No cross-linking

Inte

nsi

ty (

a.u

.)

Cross-linked - (solid-polymer)

Inte

nsi

ty (

a.u

.)

2-Theta

Cross-linked - (gel-polymer)

10 20 30 40 50

Inte

nsi

ty (

a.u

.)No cross-linking

10 20 30 40 50

Inte

nsi

ty (

a.u

.)No cross-linking

Inte

nsi

ty (

a.u

.)

Cross-linked - (solid-polymer)

No long range order & crystal structure

HPA-PVA (solid)

HPA-XLPVA (solid)

Dehydration Hydration Keggin crystal structure

HPA-XLPVA (gel)

H. Gao, K. Lian, Journal of Materials Chemistry, 22 (2012) 21272.

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Solid ECs

Metallic electrode

Stainless steel

EDLC electrode

Graphite

Pseudocapacitive

electrode

RuO2 , MoxN

22

Solid Metallic EDLC

0.0 0.2 0.4 0.6 0.8 1.0

-0.08

-0.06

-0.04

-0.02

0.00

0.02

0.04

0.06

0.08C

urr

ent

densi

ty (

Acm

-2)

Cell voltage (V)

H2SO

4 Nafion

HPA-XLPVA

5,000 V/s

23

SS

electrolyte

SS

H. Gao, K. Lian, Journal of Materials Chemistry, 22 21272.(2012)

24

0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9

-0.08

-0.06

-0.04

-0.02

0.00

0.02

0.04

0.06

0.08

Curr

ent

densi

ty (

A c

m-2

)

Cell voltage (V)

Nafion cell

SiWA-H3PO

4-PVA cell

(a) Day 1

0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9

-0.08

-0.06

-0.04

-0.02

0.00

0.02

0.04

0.06

0.08

Day 14(b)

Cu

rren

t d

en

sity

(A

cm

-2)

Cell voltage (V)

Nafion cell

SiWA-H3PO

4-PVA cell

SiWA + H3PO4 + PVA vs. Nafion®

• Polymer electrolyte) have exceeded Nafion® in stability.

Both solid EC devices are tested at an Ultra high Rate of 5000 V/s

Day 1 Day 14

H. Gao, H. Wu, K. Lian, Electrochem. Commun., Vol 12, p48 (2012)

Lian – 2013

25

0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9-0.004

-0.003

-0.002

-0.001

0.000

0.001

0.002

0.003

0.004

0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9-0.04

-0.03

-0.02

-0.01

0.00

0.01

0.02

0.03

0.04

0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9-0.08

-0.06

-0.04

-0.02

0.00

0.02

0.04

0.06

0.08

0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9-0.14

-0.12

-0.10

-0.08

-0.06

-0.04

-0.02

0.00

0.02

0.04

0.06

0.08

0.10

0.12

0.14

Cu

rren

t d

en

sity

(A

cm

-2)

Cell voltage (V)

1 Vs-1

Cu

rren

t d

en

sity

(A

cm

-2)

Cell voltage (V)

10 Vs-1

Cu

rren

t d

en

sity

(A

cm

-2)

Cell voltage (V)

25 Vs-1

Cu

rren

t d

en

sity

(A

cm

-2)

Cell voltage (V)

50 Vs-1

2.5 mF/cm2

2 mF/cm2

H. Gao, K. Lian, Journal of Materials Chemistry, 22 21272.(2012)

Solid Graphite EDLC

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26

0.0 0.4 0.8 1.2 1.6 2.00.0

0.2

0.4

0.6

0.8

1.0

Cell

volt

age (

V)

Time (s)

5 mA/cm2, 2.6 mF/cm2

0.1 1 10 100 1000 10000 100000

0.0000

0.0005

0.0010

0.0015

0.0020

0.0025

0.0030

C'

Frequency (Hz)

C' (F

cm

-2)

0.0000

0.0002

0.0004

0.0006

0.0008

0.0010

0.0012

C''

(Fcm

-2)

C''10 ms

Graphite EDLC: Charge-discharge & EIS

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27

0 2 4 6 8 10 12 14

0.0

0.2

0.4

0.6

0.8

1.0

Cell

vo

lta

ge (

V)

Time (s)

0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9-0.15

-0.10

-0.05

0.00

0.05

0.10

0.15

Cu

rren

t d

en

sity

(A

cm

-2)

Cell voltage (V)

5 Vs-1

0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9-0.04

-0.03

-0.02

-0.01

0.00

0.01

0.02

0.03

0.04

Cu

rren

t d

en

sity

(A

cm

-2)

Cell voltage (V)

1 Vs-1

30 mF/cm2 10 mF/cm2

8.3 mA/cm2, 32 mF/cm2

0.1 1 10 100 1000 10000 100000

0.000

0.005

0.010

0.015

0.020

0.025

0.030

C'

C''

Frequency (Hz)

C' (F

cm

-2)

0.000

0.002

0.004

0.006

0.008

0.010

C''

(Fcm

-2)

100 ms

RuO2 Solid pseudocapacitor

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28

Solid vs. Liquid MoxN EC Cell

Sweep rate = 1 V/s Sweep rate = 10 V/s H. Gao, K. Lian, Journal of Power Sources, 222(15) 301 (2013)

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29

Solid EC Cell at High Rates

Sweep rate = 50 V/s Sweep rate = 100 V/s

H. Gao, K. Lian, Journal of Power Sources, 222(15) 301 (2013)

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Solid vs. Liquid EC Cell – EIS Analyses

H. Gao, K. Lian, Journal of Power Sources, 222(15) 301 (2013)

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Voltage Window Expansion

Organic or Ionic Liquid Polymer Electrolytes.

Asymmetric Cell

Multi-cell-in-One package

31

32

Electrolyte coated on electrode active material • Polymer/acid gel blends • Thin film polymer

electrolyte 30 to 50m

Electrode active materials coated on substrate

• Activated/modified carbon • Mixed metal oxides • Conductive polymers • CNT

Asymmetrical Polymer-based Capacitor

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33

Fabrication of Solid Asymmetric Cell

Pressure and

temperature

Film conductivity 0.01 S/cm

Thickness 0.4 – 0.6 mm

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Solid Asymmetric Ecs (graphite-RuO2)

0 0.5 1.0 1.5

-0.0050

-0.0025

0

0.0025

0.0050

E (Volts)

I (A

mp

s/c

m2)

GRAPHITE-PTA-629-100(14)-DAY1.cor

5 10 15 20 25

0

0.5

1.0

1.5

Time (Sec)

E (

Vo

lts)

GRAPHITE-PTA-629-1000(14)-DAY4-CHARGE-DISCHARGE-100.cor

K. Lian et.al, Electrochemistry Communications 12(4) 517 (2010)

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Lian – Oct. 2012

35

Terminal electrode

• Multi-cell EC in single package

– Two ECs in series (bipolar plate)

– Smaller device capacitance

– Higher cell voltage window

Solid multi-cell-in-one package ECs

Bipolar electrode

Polymer electrolyte

Terminal electrode

36

At 5,000 V/s scan rate

0.0 0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6 1.8

-0.04

-0.03

-0.02

-0.01

0.00

0.01

0.02

0.03

0.04

Curr

ent

densi

ty (

A c

m-2)

Cell voltage (V)

Cycle No. 100

0.0 0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6 1.8

-0.04

-0.03

-0.02

-0.01

0.00

0.01

0.02

0.03

0.04

Curr

ent

densi

ty (

A c

m-2)

Cell voltage (V)

Cycle No. 100

Cycle No. 20,000

Solid Metallic 2-cell-in-1 EC

• Increased voltage window and excellent cycle life

H. Gao, H. Wu, K. Lian, Electrochem. Commun., Vol 12, p48 (2012)

SS

Poly electrolyte

SS

Poly electrolyte

SS

Lian – 2013

37

0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9

-0.008

-0.006

-0.004

-0.002

0.000

0.002

0.004

0.006

0.008

1 Vs-1

Cu

rren

t d

en

sity

(A

cm

-2)

Cell voltage (V)

Solid Carbon Based 2-cell-in-1 EDLC

Single Cell

0.0 0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6 1.8

-0.003

-0.002

-0.001

0.000

0.001

0.002

0.003

Cu

rren

t d

en

sity

(A

cm-2

)

Cell voltage (V)

1 Vs-1

2-Cell-in-1 package

Electrodes: Graphite on Stainless Steel foils

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0.0 0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6 1.8

-0.003

-0.002

-0.001

0.000

0.001

0.002

0.003

Cu

rren

t d

en

sity

(A

cm

-2)

Cell voltage (V)

1 Vs-1

Solid Carbon Based 2-cell-in-1 EDLC

0.0 0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6 1.8

-0.020

-0.015

-0.010

-0.005

0.000

0.005

0.010

0.015

0.020

Cu

rren

t d

en

sity

(A

cm-2

)

Cell voltage (V)

10 Vs-1

0.0 0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6 1.8

-0.04

-0.03

-0.02

-0.01

0.00

0.01

0.02

0.03

0.04

Cu

rren

t d

en

sity

(A

cm-2

)

Cell voltage (V)

25 Vs-1

0.0 0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6 1.8

-0.06

-0.04

-0.02

0.00

0.02

0.04

0.06

Cu

rren

t d

en

sity

(A

cm-2

)

Cell voltage (V)

50 Vs-1

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39

1 10 100 1000 10000 1000000.0

0.5

1.0

1.5

2.0

2.5

3.0

3.5

4.0

1 10 100 1000 10000 1000000.0

0.2

0.4

0.6

0.8

1.0

1.2

C'

(mF

cm

-2)

Frequency (Hz)

Single cell

Multi-cell

C''

(m

F c

m-2

)

Frequency (Hz)

Single cell

Multi-cell

Solid Carbon Based 2-cell EC (Impedance)

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Latest: Alkaline based solid electrolyte

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40

Rate: 2000 V/s 50C to -10C

41

Summary

• SiWA - H3PO4 – PVA electrolytes have been

shown to

1. perform equal or better than liquid aqueous electrolyte;

2. be applicable for both EDLC and pseudocapacitors.

3. store and deliver charge at ultrahigh rates;

4. retain its conductivity and ultrahigh rate capability over

time, yielding excellent shelf and cycle life;

5. enable multi-cell ECs in single package without

sacrificing rate capability.

• Solid polymer electrolytes are viable for high rate

and high power energy storage devices.

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42

Acknowledgement • Electrolytes:

– Han Gao, Sanaz Ketabi, Haoran Wu, Jak Li, Alex Dilio and

Blair Decker

• Electrodes

– Gurvinder Bajwa, Fred Xiao, Matt Genovece, Terence Lee

• Applications

– Jin Chang, Ahmed Huzayin, Bernie Ting,

• NSERC Canada

• Ontario Research Fund

• Ontario Center of Excellence

• University of Toronto

Lian – 2013