Alberto Ansaldo - Access€¦ · • Screen printed (flexible) supercapacitors Salerno - 31 May 2018 International Workshop on Supercapacitors and Energy Storage 2 . Capacitors vs

Alberto Ansaldo

Salerno - 31 May 2018

International Workshop on Supercapacitors and Energy Storage 1

Outlook

• Capacitors vs batteries vs supercapacitors

• Graphene/CNT hybrid supercapacitors

• Graphene membrane supercapacitors

• Screen printed (flexible) supercapacitors

Salerno - 31 May 2018 International Workshop on Supercapacitors and Energy Storage 2

Capacitors vs Batteries


Capacitors Electrolytic Capacitors

EDLCs Batteries

Insulator Yes Yes - -

Surface charge

Yes Yes Yes -

Electrolyte - Yes Yes Yes

Redox - - - Yes

Volume charge

- - - Yes

Double layer - - Yes -

Adapted from A.C.Ferrari et al., Nanoscale 7, 4587 (2015)

Carbon Nanotubes vs Graphene


+

+

2nm 3nm

+

+

0.5 nm 200nm

In an electrode made from cast graphene material the path can be incredibly long. The larger the flake, the longer the path.

http://upload.wikimedia.org/wikipedia/commons/a/ae/Potassium-graphite-xtal-3D-SF-A.png

Carbon Nanotubes vs Graphene


Vertical arrangement can fix the problem but requires overcomplicated fabrication methods. Hybrid materials can be a more feasible strategy

+

+

200 nm 200nm

+

+

2nm 3nm

http://upload.wikimedia.org/wikipedia/commons/a/ae/Potassium-graphite-xtal-3D-SF-A.png

Dynamic Spray Gun Deposition


Process advantages:

• Allow co-deposition of

different carbon-based

materials

• Film morphology can be

monitored during

deposition

• Scalable

Graphite/CNT EDLCs by DSG Deposition


P. Bondavalli et al., J. Electrochem. Soc. 160, A601 (2013)

•Flexible substrate (Graphite paper)

•Different Graphite/CNTs ratios

•Cheap and safe electrolyte (aqueous 3M LiNO3)

160 nm

23 nm

6 nm

200 nm

Graphene/CNT hybrid Supercapacitors

Graphene ink preparation

•Liquid Phase Exfoliation

•Graphite in NMP

•Bath sonication

•Size selection by Sedimentation Based Separation

•TEM lateral size ~ 230nm

•AFM thickness ~ 2.6nm

0 5 10 150

15

30

Mode 2.6 nm

Log-norm. std. dev. 0.46

%

Thickness (nm)

0 250 500 750 10000

10

20

Mode 230 nm

Log-norm. std. dev. 0.81

%

Lateral size (nm)

A. Ansaldo et al. ChemNanoMat 3, 436 (2017)



•Hybrid ink preparation

•SWCNTs: Length 0.5-5 µm Diameter 0.7-2.5 nm

•0.5g/L in NMP

•Tip sonication

•1:1 mix with Graphene ink

•Dynamic Spray Gun Deposition






•Temperature >200 °C

•Collector Graphite paper

•Electrodes area 2cm2

•Deposited hybrid 1.15mg

•Electrolyte aqueous 3M LiNO3



























Benchmark

•Commercially available carbon black material (PICACTIF)

•Buckypaper hybrid electrodes obtained by vacuum filtration




Electrochemical characterization

•Cyclic voltammetry in 3 electrode configuration

-0.5 0.0 0.5

-2

0

2

I (A

g-1)

E (V vs. Ag/AgCl)

PICACTIF

Scan rate 20 mV s-1

-0.5 0.0 0.5

-2

0

2

I (A

g-1)

E (V vs. Ag/AgCl)

PICACTIF

SLG/FLG-SWCNTs BP

Scan rate 20 mV s-1

-0.5 0.0 0.5

-2

0

2

I (A

g-1)

E (V vs. Ag/AgCl)

PICACTIF

SLG/FLG-SWCNTs BP

SLG/FLG-SWCNTs DSGScan rate 20 mV s-1






0 100 200 300 400 5000

20

40

60

80

100 PICACTIF

Capacitance(F

g-1)

Scan rate (mV s-1)

0 100 200 300 400 5000

20

40

60

80

100 PICACTIF

SLG/FLG-SWCNTs BP

Capacitance(F

g-1)

Scan rate (mV s-1)

0 100 200 300 400 5000

20

40

60

80

100 PICACTIF

SLG/FLG-SWCNTs BP

SLG/FLG-SWCNTs DSG

Capacitance(F

g-1)

Scan rate (mV s-1)






Assembled capacitors testing

•Galvanostatic Charge/Discharge

-1 0 1 2 3 4 5 6 7

0.0

0.2

0.4

0.6

0.8

1.0

1.2

E (

V)

time (s)

initial

-1 0 1 2 3 4 5 6 7

0.0

0.2

0.4

0.6

0.8

1.0

1.2

E (

V)

time (s)

initial

after 1000 cycles

-1 0 1 2 3 4 5 6 7

0.0

0.2

0.4

0.6

0.8

1.0

1.2

E (

V)

time (s)

initial

after 1000 cycles

after 2000 cycles

-1 0 1 2 3 4 5 6 7

0.0

0.2

0.4

0.6

0.8

1.0

1.2

E (

V)

time (s)

initial

after 1000 cycles

after 2000 cycles

after 3000 cycles

-1 0 1 2 3 4 5 6 7

0.0

0.2

0.4

0.6

0.8

1.0

1.2

E (

V)

time (s)

initial

after 1000 cycles

after 2000 cycles

after 3000 cycles

after 4000 cycles

after 5000 cycles

-1 0 1 2 3 4 5 6 7

0.0

0.2

0.4

0.6

0.8

1.0

1.2

E (

V)

time (s)

initial

after 1000 cycles

after 2000 cycles

after 3000 cycles

after 4000 cycles

after 5000 cycles






Assembled cap testing

•Galvanostatic Charge/Discharge

•Cyclic voltammetry (every 1000 GCD)

0.0 0.2 0.4 0.6 0.8 1.0 1.2

-0.6

-0.4

-0.2

0.0

0.2

0.4

0.6

I (A

g-1)

E (V vs. Ag/AgCl)

Initial

0.0 0.2 0.4 0.6 0.8 1.0 1.2

-0.6

-0.4

-0.2

0.0

0.2

0.4

0.6

I (A

g-1)

E (V vs. Ag/AgCl)

Initial

after 1000 cycles

0.0 0.2 0.4 0.6 0.8 1.0 1.2

-0.6

-0.4

-0.2

0.0

0.2

0.4

0.6

I (A

g-1)

E (V vs. Ag/AgCl)

Initial

after 1000 cycles

after 2000 cycles

0.0 0.2 0.4 0.6 0.8 1.0 1.2

-0.6

-0.4

-0.2

0.0

0.2

0.4

0.6

I (A

g-1)

E (V vs. Ag/AgCl)

Initial

after 1000 cycles

after 2000 cycles

after 3000 cycles

0.0 0.2 0.4 0.6 0.8 1.0 1.2

-0.6

-0.4

-0.2

0.0

0.2

0.4

0.6

I (A

g-1)

E (V vs. Ag/AgCl)

Initial

after 1000 cycles

after 2000 cycles

after 3000 cycles

after 4000 cycles

0.0 0.2 0.4 0.6 0.8 1.0 1.2

-0.6

-0.4

-0.2

0.0

0.2

0.4

0.6

I (A

g-1)

E (V vs. Ag/AgCl)

Initial

after 1000 cycles

after 2000 cycles

after 3000 cycles

after 4000 cycles

after 5000 cycles


This paper

• Capacitance 104 F g-1 62 mF cm-2

• Cycle life >5000 cycles

• Coulombic efficiency ~100%

• Energy density ~21 Wh kg-1

• Peak Power density ~92 kW kg-1

• Voltage window 1.2 V

Literature

~ 200 F g-1 [1,2]

~ 60 Wh kg-1 in organic solvents[1,2]

~ 58.5 kW kg-1 in organic solvents[2]

[1] Z. J. Fan, et al., Adv. Mater., 22, 3723 (2010).

[2] Q. Cheng et al., Phys. Chem. Chem. Phys., 13, 17615 (2011)



Screen printed (flexible) supercapacitors

Ink production

•Filler graphene powder (WJM not purified) 75 g/L

•Solvent EtOH/H2O [30:70]

•Thickening agent terpineol 1 wt%

Good printability on: • Glass • PET • nylon membranes • duroid…



Capacitor design

• Planar interdigitated electrodes

• Graphene based electrodes

• Solid electrolyte (H3PO4 @ PVA)


0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8-1500

-1000

-500

0

500

1000

Cu

rre

nt

(A

/cm

2)

Potential (V)

10 mV/s 2000 mV/s

50 mV/s 5000 mV/s

200 mV/s 10000 mV/s

1000 mV/s 20000 mV/s



0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8-1500

-1000

-500

0

500

1000

Cu

rre

nt

(A

/cm

2)

Potential (V)

10 mV/s 2000 mV/s

50 mV/s 5000 mV/s

200 mV/s 10000 mV/s

1000 mV/s 20000 mV/s

0.01 0.1 1 100

20

40

60

80

100

120

140

160

180

Are

al ca

pa

cita

nce

(

F/c

m2)

Scan rate (V/s)



0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0

0.0

0.2

0.4

0.6

0.8

Pote

ntial (V

)

Time (s)

2

3

4

5

6

7

8

9

10

20

30

50

90

100

200

300

500

900

1000

3000

4000

9000

10000

2 4 6 8 10 100 1000 1000060

80

100

Capacitance r

ete

ntion (

%)

cycles (#)

60

80

100

Coulo

mbic

effic

iency (

%)

• Capacity retention over 10000 cycles: 91% • Columbic efficiency ~100%


Bending stability


1 10 1000

20

40

60

80

100

Ca

pa

cita

nce

re

ten

tio

n (

%)

Bending cycles (#)

R = 2 cm

R = 1 cm

0.0 0.5 1.0 1.5 2.00

20

40

60

80

100

0

20

40

60

80

100

Cap

acita

nce r

ete

ntion

(%

)

Bending radius (cm)

Cou

lom

bic

eff

icie

ncy (

%)

0 90 1800

20

40

60

80

100

0

20

40

60

80

100

Cap

acita

nce r

ete

ntion

(%

)

Bending angle (°)

Cou

lom

bic

eff

icie

ncy (

%)

Conclusions and prespectives

Targets:

• Target capacitance >300F/g

• Volumetric capacitance >150 F/cm3

• SSA>1500 m2/g (avg pore 1nm)

• Production capability 10g/day

• Flexible supercapacitor

Current results

• >100 F/g

• ~10 F/cm3 (current commercial 0.5 F/cm3)

• Not verified yet.

Pore >6nm should be preferable

• About 120g/week

• Both DSG and printed device tested


IIT Graphene Labs

Alberto Ansaldo

Sebastiano Bellani

Antonio Esau Del Rio Castillo

Vittorio Pellegrini

Francesco Bonaccorso

Former Members

Gianluca Longoni

Elisa Petroni

Luca Galliani

Università di Cagliari and IIT

Nicola Curreli

IIT Materials Charaterization

Mirko Prato

Thales

Paolo Bondavalli

Grégory Pognon

Acknowlegments


Fundings

Graphene flagship WP12 Energy Storage


Documents

Alberto Ansaldo - Access€¦ · • Screen printed (flexible) supercapacitors Salerno - 31 May 2018 International Workshop on Supercapacitors and Energy Storage 2 . Capacitors vs