1) The document analyzes Co3O4@x%rGO (where x=0%, 5%, 10%, 15%) composites as electrode materials for supercapacitors. 2) Characterization of the materials showed Co3O4@15%rGO had the best performance with higher specific capacitance and energy/power densities. 3) Testing included XRD, CV, GCD, EIS and found Co3O4@15%rGO to have highly crystalline cubic structures, pseudocapacitive behavior, and longer discharge times than other compositions.

1. Analysis of Co3O4@ x % rGO (x =0%,5%,10%,15%) as Effective Electrode Material
in Supercapacitors
Presented By : Jahanzaib Mughal
Roll No: CSSP-R41-F21
Session: 2021-23
Supervised by : Dr.Shahid Atiq
CENTER OF EXCELLENCE IN SOLID STATE PHYSICS,
UNIVERSITY OF THE PUNJAB,
LAHORE (QAC)
Center of excellence
in solid state physics

2. Super + capacitor
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3.  Higher Energy Density
 Higher Power Density
 Higher Capacity
 Longer Life
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Things that makes a
capacitor, super

4. Properties Capacitor Supercapacitor Battery
Energy density
(Wh/kg)
˂0.1 1-10 10-100
Power density
(W/kg)
>1,000,000 10,000 1000
Discharging time
(sec)
10-3 – 10-6 1-30 >0.3 h
Charging time (sec) 10-3 – 10-6 1-30 1˂t>5 h
Cyclic stability 106 106 1,000
Materials Science and Engineering. 561. 012105. 10.1088/1757-899X/561/1/012105.
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Comparison between different
energy storage devices

5. 9/14/2023 4
What is Supercapacitor ?
Current collectors
An energy storage device having capacitance in
between 100F to 5kF with higher power density and
cyclic life than batteries and higher energy density than
conventional capacitors, is called Ultracapacitor or
Supercapacitor.
Based on the charge storage mechanism, it can be
classified in 2 basic types
• Electric double layer capacitors
• Pseudo capacitors

6. 9/14/2023 5
Charge Storage
Mechanism
Electro Static
Charge Storage
Mechanism
Electro Dynamic
Charge Storage
Mechanism

7. Electric + Hodos
Charge + way/ path
Conductors that are used to make electric contacts with non-metallic
part of the circuit
Type
(-ve charge) Cathod Anode (+ve charge)
Electrodes
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8. 9/14/2023 7
Most Preferred Electrode
materials

9. Motivation behind
Ideal electrode
• Conductive
• Maximal surface area
• Mechanical stability
• Clear and sharp melting
temperatures
• Minimal internal resistance
• Appropriate electrolyte interaction
• Good specific capacitance
Co3O4
.
.
.
.
.
.
.
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10. 9/14/2023 9
Literature Review

11. Electrode Fabrication
Graphical abstract
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12. Hydrothermal Synthesis Route
Co(NO3)2 + DI water C₂H₆O₂
HNO3
autoclave
Teflon container
Centrifuge washing
Muffle furnace
4h at 140º
oven
Mortar & pestle
Box furnace
2h at 550º
Co3O4
nano particles

13. Preparation of Active Material by Solvothermal Method
Aqueous Solution
Ultrasonic Bath Stirring Teflon Box & Autoclave
Muffle Furnace
Centrifuge
Heating
Active Mass
Co3O4 + x % rGO + Ethanol Sonification for 40 mints Stirring for 4 hours
Aqueous Solution in
autoclave
Constant heating at
60℃ 𝐟𝐨𝐫 𝟐 𝐡𝐨𝐮𝐫𝐬
Kept for 5
hours at 140 ℃
Washing
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14. Preparation of Slurry
Active Mass 85%
Binder 10%
Activated Carbon 5%
Stirring For 8 hours
Slurry
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PVDF + DMF

15. 50ml Etching
Solution
Ni Foam Ni Foam dipped in
Etching Solution
Ultrasonic Bath
Oven
Oven
Prepared Electrode
13ml of HCL 37ml of DI Water
Cutting of Ni Foam
of Size 1× 𝟏 (𝐜𝐦)
Sonification Etching Sol.
Ni Foam kept for
20 Mints
drying for 20 Mints
Coating on Ni
Foam
Coating of slurry
Preparation of Electrode
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16. X-ray Diffraction
For structural conformations
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17. Equinox 2000,
Thermo Fisher Scientific USA
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Characterization
Apparatus

18. 10 20 30 40 50 60 70 80
¨
¨
Co3O4 +10% rGO
Co3O4 +5% rGO
Co3O4 + 0% rGO
Intensity
(Arb.
units)
2q
(
Degree)
Co3O4 +15% rGO
©
©
© Ni (foam)
ICSD card # 00-004-0850
¨
¨
¨
¨
¨
¨
¨ Co2O4
ICSD card # 00-042-1467
©
9/14/2023 17
XRD Pattern

19. • Calculated parameters
α=β=γ=90°
a=b=c=8.065 Å
Cubic structure
Cell volume 524.5 Å3
• ICSD card parameters
α=β=γ=90°
a=b=c=8.083 Å
Cubic structure
Cell volume 528.54 Å3
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Comparison of
Lattice Parameters

20. • The portion of crystal which diffracts the light coherently, is know as
crystallite size
𝑫 =
𝒌𝝀
𝜷𝒄𝒐𝒔𝜽
k is the shape factor having a constant value of 0.9.
9/14/2023 19
Crystallite size

21. 9/14/2023 20
Variation in
Crystallite size
0 5 10 15
0
5
10
15
20
25
30
35
40
Crystalite
size
(nm)
rGO Composition (%)
Crystalite size of Co3O4 @ x % rGO
25.43 nm
24.49 nm 24.19 nm 24.00 nm

22. Cyclic Voltammetry
To observe the redox reaction route

23. OGS 2000 Origalys Potentiostate
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Characterization
Apparatus

24. 0.0 0.1 0.2 0.3 0.4
-0.04
-0.02
0.00
0.02
0.04
0.06
Current
(A)
Potential (V)
5mV/s
10mV/s
20mV/s
30mV/s
50mV/s
100mV/s
Co3O4 @ 0% rGO
(a)
0.0 0.1 0.2 0.3 0.4
-0.04
-0.02
0.00
0.02
0.04
0.06
Current
(A)
Potential (V)
5mV/s
10mV/s
20mV/s
30mV/s
50mV/s
100mV/s
Co3O4 @ 5% rGO
(a)
CV curves in 2M KOH electrolyte with (a) Co3O4 @ 0% rGO (b) Co3O4 @ 5% rGO
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CV curves

25. 9/14/2023 24
0.0 0.1 0.2 0.3 0.4
-0.04
-0.02
0.00
0.02
0.04
0.06
Current
(A)
Potential (V)
5mV/s
10mV/s
20mV/s
30mV/s
50mV/s
100mV/s
Co3O4 @ 10% rGO
(c)
0.0 0.1 0.2 0.3 0.4
-0.04
-0.02
0.00
0.02
0.04
0.06
Current
(A)
Potential (V)
5mV/s
10mV/s
20mV/s
30mV/s
50mV/s
100mV/s
Co3O4 @ 15% rGO
(b)
CV curves in 2M KOH electrolyte (c) Co3O4 @ 10% rGO (d) Co3O4 @ 15% rGO
CV curves

26. Galvanostatic Charge-Discharge
Measurements
For performance of energy storage devices

27. Galvano-state Impedance meter,
Origa Stat OGS 2000
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Characterization
Apparatus

28. 9/14/2023 27
0 50 100 150 200 250 300
0.0
0.1
0.2
0.3
0.4
Potential
(V)
Time (sec)
1A/g
2A/g
3A/g
4A/g
Co3O4 + 0% rGO
(a)
-100 0 100 200 300 400 500 600 700
0.0
0.1
0.2
0.3
0.4
Potential
(V)
Time (sec)
1A/g
2A/g
3A/g
4A/g
Co3O4 + 5% rGO
(b)
GCD curves in 2M KOH electrolyte with (a) Co3O4 @ 0% rGO (b) Co3O4 @ 5% rGO
GCD Curves

29. 9/14/2023 28
0 100 200 300 400 500 600 700
0.0
0.1
0.2
0.3
0.4
Potential
(V)
Time (sec)
1A/g
2A/g
3A/g
4A/g
Co3O4 + 10% rGO
(c)
-100 0 100 200 300 400 500 600 700 800
0.0
0.1
0.2
0.3
0.4
Potential
(V)
Time (sec)
1A/g
2A/g
3A/g
4A/g
Co3O4 + 15% rGO
(d)
GCD curves in 2M KOH electrolyte with (c) Co3O4 @ 10% rGO (d) Co3O4 @ 15% rGO
GCD Curves

30. Sample 1A/g 2A/g 3A/g 4A/g
Discharge
time (sec)
Specific
capacitance
(F/g)
Discharge
time (sec)
Specific
capacitance
(F/g)
Discharge
time (sec)
Specific
capacitanc
e (F/g)
Discharge
time (sec)
Specific
capacitance (F/g)
Co3O4 @0% rGO 132.882 332.205 46.359 231.795 22.651 169.882
5
7.7 77
Co3O4 @5% rGO 275.795 689.4875 86.206 431.03 27.126 203.445 6.318 63.18
Co3O4 @10% rGO 296.527 741.3175 125.918 629.598 29.933 299.497
5
9.521 95.21
Co3O4 @15% rGO 320.888 802.22 122.455 612.275 59.315 444.862
5
21.123 211.23
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Specific Capacitance at Different Current Densities

31. 9/14/2023 30
0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5
0
200
400
600
800
Specific
Capacitance
(F/g)
Current Density (A/g)
Co3O4 @ 0% rGO
Co3O4 @ 5% rGO
Co3O4 @ 10% rGO
Co3O4 @ 15% rGO
Trend of Specific Capacitance with increasing Current Densities along with the error correction
Specific Capacitance Vs
Current Density

32. 9/14/2023 31
0.2 0.3 0.4 0.5 0.6 0.7 0.8
0
10
20
30
40
50
60
70
Energy
Density
Wh/kg
Power Density (W/kg)
Co3O4 @ 0% rGO
Co3O4 @ 5% rGO
Co3O4 @ 10% rGO
Co3O4 @ 15% rGO
Power Vs Energy Density

33. 9/14/2023 32
Electroscopic Impedance
Spectroscopy
Capacitive & resistive behavior

34. 9/14/2023 33
EIS Curves
2.0 2.1 2.2 2.3 2.4 2.5 2.6 2.7 2.8 2.9 3.0
-0.4
0.0
0.4
0.8
1.2
1.6
-Z"(W)
Z'(W)
Co3O4 @ 0% rGO
(a)
1.7 1.8 1.9 2.0 2.1
0.0
0.2
0.4
0.6
0.8
Z''
(W)
Z'(W)
Co3O4 @ 5% rGO
(c)

35. 9/14/2023 34
EIS Curves
2.10 2.15 2.20 2.25 2.30 2.35 2.40
0.0
0.2
0.4
0.6
-Z"(W)
Z' (W)
Co3O4 @ 15% rGO
(d)
1.4 1.5 1.6 1.7
-0.2
0.0
0.2
0.4
0.6
0.8
-Z"(W)
Z'(W)
Co3O4 @ 10% rGO
(b)

36. • Highly pure crystalline cubic structures are confirmed by XRD with
average crystallite size of 24.4 Å
• CV curves confirms the pseudo capacitive behavior of Co3O4 @ x %
rGO composites
• Comparatively, better energy and power densities are observed of
Co3O4 @ 15% rGO composite along with longer discharging time
• An unexpected specific capacitance at 2A/g is observed with Co3O4
@ 10% rGO
9/14/2023 35
Conclusion

37. 9/14/2023 36
Co3O4 @ 15% rGO composite
is preferable for practical device
fabrication at low current
densities
Remarks

38. 9/14/2023 37
Acknowledgment
Center Of Excellence in Solid State Physics, PU
Department of physics, COMSATS University
US Pecas, NUST
DS&T, University of Education
Dr. Shahid Atiq
Mr.Umer Waqas
Mr. Amaar Tariq
Special Thanks

39. Suggestions
please
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40. Thank you
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