M.Aadil

2. SUPERCAPACITORS
Muhammad Aadil (Ph.D Scholar)
Session (2017-2021)
DEPARTMENT OF CHEMISTRY
The Islamia University of Bahawalpur

3. CONTENTS
 Need of Energy Storage
 Devices commonly used for Energy storage
 Comparison among Energy storage devices
 History of Supercapacitors (SCs)
 Merits and Demerits of Supercapacitors
 Applications of Supercapacitors
 Strategies to improve energy density of SCs
 Role of Electrode materials
 Role of electrolytes
 Electrochemical measurements
Asymmetric electrode to increase

4. Growing Population Depletion of Fossil Fuels
Trend of Portable Devices Discontinuous nature of Renewable Resources
NEED OF ENERGY STORAGE DEVICES

5. Energy
Storage
Devices
COMMON ENERGY STORAGE DEVICES

6. COMPARISON AMONG ENERGY STORAGE
DEVICES
Charging Time
Capacitors Batteries
1-10s 1-10s 10-60 minutes
Cyclic Life 1000000 1000000 500-1000
Service Life 10-15 Years 10-15 Years 5-10 Years
Cell Voltage Drop Remain sameDrop
Energy density Moderate Low Very High
Power density High High Low
Weight 1-10g 1-10g 1g-10kg
Storage
Mechanism Static ElectrochemicalStatic/EC
Charging OverNot overNot over

7. Powerdensity(W/kg)
Energy density (Wh/Kg)
Capacitors
Supercapacitors
Batteries Fuel cells
10 4
10 6
10 3
10 5
107
10 2
10
10110 -1 10 2
10 310 -2
RAGONE PLOT

8. Battery
SCs

9.  In 1957 Becker employed 1st time porous carbon electrode in
capacitors
 In 1970 SOHIO company introduce 1st electrochemical capacitors
for commercial applications
 In 1978 NEC (Nippon Electric Company) introduced the term“Supercapacitor”
 In 1990s Conway’s group developed the concept of “pseudo
capacitance”
 In 2006 Zhang and Hu introduced hybrid electrode material strategy
(K. Samantara and Ratha 2018)
HISTORY OF SUPERCAPACITORS

10.  High power density
 High Cyclic efficiency (95%)
 Good cryogenic properties
 Environmental friendly nature
 Wide range of operating temperature
 High rate capability
 Shorter charging time
 Longer life
WHY SUPERCAPACITORS?

11. APPLICATIONS OF SUPERCAPACITORS
Load Lifter Renewable energy Power plant
Hybrid Electrical Vehicles Large Industrial equipments

12. WHY NOT BATTERIES?
 Low power density
 Poor cycle life (shelf life)
 Low power density
 Self-discharging (Fast at high temperature),
 Expensive and fire hazards nature
(Kumar, Choudhary et al. 2018)

13. DRAWBACKS OF SUPERCAPACITORS
SCs
Low Energy density
(Sk, Yue et al. 2016)

14. PARTS OF EDLC SCS
1- Electrode
2-Electrolyte
3-Separator
4-Current Collector
https://doi.org/10.1149/2.017310jes

15. STRATEGY TO IMPROVE ENERGY DENSITY
Formula of energy density
C = Specific capacitance
V = Potential window

16. FACTOR AFFECTING SPECIFIC CAPACITANCE
1- Nature of electrode material (High conductivity)
2- Structure of electrode material (Porous)
3- Surface area of the electrodes
4- Distance between the plates
5- Dielectric Permittivity of the medium
6- Effect of binder, effect of electrolyte concentration, effect of electrode
thickness, effect of redox active substances
(Tsay, Zhang et al. 2012)
(Azari, Rahmanifar et al. 2017)

17. ELECTRODE MATERIALS (EMS)
1- Carbon Based materials
2- Transition metal oxides (TMOs)
3- Conducting Polymers (CPs)
Activated Carbon Graphene
CNTCarbon aerogels
Carbon nanofibirs
Ru2O IrO2 MnO2 NiO SnO2
MoO3 WO3 V2O5 CuO
Polyaniline Polythiophene Polypyrrol

18. CLASSIFICATION OF SCS BASED ON EMS
SCS
EDLCPseudo -capacitor
Based on EDL Materials
( Carbon based Materials)
Based on Redox Materials
(TMOs & CPs) Hybrid
SCs
Based on composite of EDL & Redox Materials
Symmetric 1st GenerationSymmetric 2nd Generation
Asymmetric 3rd Generation
(Ji, Ji et al. 2015)

19. FEATURES OF NOVEL EMS
 High electronic Conductivity
 High surface area
 Controlled pore structure
 Low Cost
 High temperature and cyclic stability
 High theoretical capacitance
 Good corrosion resistance
(Kate, Khalate et al. 2018)

20. CARBONACEOUS MATERIALS
MERITS/DEMERITS /SOLUTION
MERITS
 Thermal /Chemical /Cyclic stability
 Good electrical conductivity
DEMERITS
 Low specific capacitance
SOLUTION OF THE PROBLEM
 Their Nanostructure formation with TMOs improved the specific capacitance
 High surface area
 Low cost
(Parveen, Ansari et al. 2017)

21. TMOS MERITS/DEMERITS /SOLUTION
MERITS OF TMOs
 High theoretical capacitance
 Store charge by fast faradic process
DEMERITS OF TMOs
 Less surface area
 Poor cyclic performance
 Low conductivity
SOLUTION OF THE PROBLEM
 Nanostructure formation of TMOs improved its surface area
Composite Formation with carbonaceous materials improve their conductivity

22. CPS MERITS/DEMERITS /SOLUTION
MERITS OF CPs
 Controlled conductivity
 Low cost
 Low Equivalent series resistance
DEMERITS OF CPs
 Poor cyclic stability
 Less specific capacitance
 Less surface area
SOLUTION OF THE PROBLEM
 Composite formation of CPs with TMOs improved its specific capacitance
 Composite formation of CPs with Carbonaceous materials improved its
surface area and cyclic stability

23. ROLE OF ELECTROLYTES IN SCS
 Electrolytes nature controlled the Potential window (V)
 P.W is the voltage range between which electrolyte neither oxidized or reduced
 P.W is calculated as
P.W = Reduction Potential – Oxidation potential
 Aqueous electrolyte have less P.W due to dissociation of water
P.W = Cathodic limit– Anodic limit
OR
 Ionic resistivity in electrolyte reduce the Power density of the SCs
 Low concentration of electrolyte reduce P.W and Energy density
 Interaction b/w electrolyte and electrode material control the cyclic stability

24. FEATURES OF NOVEL ELECTROLYTE
 Wide potential window
 High ionic mobility / high e resistivity
 Low solvated ionic radius
 Low viscosity and volatility
 High purity and safety
 Low toxicity and cost
 Moderate concentration
(Wang, Zhang et al. 2012)

25. CLASSIFICATION OF ELECTROLYTES
ELECTROLYTES
Liquids ELsSolid ELs
Polymer ELs Inorganic ELs
Organic ELsAqueous ELs
Acidic ELs Neutral ELsBasic ELs
(Zhao and Zheng 2015)

26. AQUEOUS ELECTROLYTES (AELS)
MERITS OF AELs
 High Conductivity & concentration of ions ( low ESR)
 Low ionic resistivity and cost
 Environmental friendly and non- corrosive nature
 Low viscosity but high safety
DEMERITS OFAELs
 Low Potential window
SOLUTION OF THE PROBLEM
 Super-concentrated salt solution can extend P.W up to 3.0V
 P.W of AELs can also be improved by using a symmetric configuration
EXAMPLES H2SO4 Na2SO4 KOH

27. ORGANIC ELECTROLYTES (OELS)
MERITS OF AELs
 Wide potential window
 Low ionic conductivity (high ESR)
 High Toxicity and volatility
 High flammability and cost
DEMERITS OF AELs
 High viscosity
Examples
Acetonitrile Propylene carbonate

28. SOLID ELECTROLYTES (SELS)
 Solid electrolytes further classified into Polymer and Ionic
solid electrolytes
 Polymer electrolytes may be “Dry polymer” or “Gel Polymer”
 Gel polymer have advantage due to High ionic conductivity
 Ionic solid electrolyte may be Crystalline , amorphous or Mixed

29. CAPACITIVE BEHAVIOR OF ELECTRODE
MATERIALS
 Cyclic Voltammetery (CV) experiments
 Galvanic charge-discharge curve
 Electrochemical impedance spectroscopy (EIS)

30. CYCLIC VOLTAMMETRY (CV)
Specific capacitance Formula
Ccv = I / (ΔV/ Δt) m
I = current
ΔV/ Δt = Potential sweep rate
m = mass of deposited analyte
Basic Purpose To measure Voltage windowTo measure Specific capacitance
To measure cyclic life

31. GALVANOSTATIC CHARGE
DISCHARGE CYCLE
A wide triangle at low current density
A narrow triangle at high current density

32. ELECTROCHEMICAL IMPEDANCE SPECTROSCOPY
Basic Purpose To measure ESR of SCsTo measure Capacitance of SCs
To measure non- Ideality of a SCs
Formula For Specific capacitance
CEIS = 1 / m x J x 2πf x Z ⸗
 Semicircle indicate the Rct
 Vertical line represent the fast ion
diffusion (EDLC)
Nyquist Impedanc

34. THANK YOU