This document describes the development of a hybrid supercapacitor combining lithium-ion battery electrodes and carbon-based supercapacitor electrodes. Specifically, it discusses synthesizing lithium manganate and doped lithium manganate compounds as cathode materials, and using carbon nanofoam as the anode material. The hybrid supercapacitor is fabricated and undergoes electrochemical characterization through impedance spectroscopy, cyclic voltammetry, and galvanostatic charge/discharge testing to analyze its performance.

1. DEVELOPMENT OF NON-AQUEOUS
ASYMMETRIC HYBRID SUPERCAPACITORS
BASED ON Li-ION INTERCALATED
COMPOUNDS
GUIDE
BY
Dr.D.KALPANA, SCIENTIST,
EEC DIVISION,
NAKKIRAN.A
CECRI,
KARAIKUDI.

2. INTRODUCTION
WHAT IS A CAPACITOR?
capacitor is a device used for storing charges and energy in its simplest
form.
A capacitor consists of two conducting surfaces separated by an insulating
material ( Dielectric).
PRINCIPLE:

4. What are Supercapacitors?
Supercapacitors are an advanced version of capacitors with
unique ability to combine energy storage capabilities of
batteries and power storage behavior of capacitor.
Hence fill the gap between batteries and conventional
capacitors such as the electrolyte capacitors in terms of specific
energy as well as specific power.

5. PROPERTIES OF ENERGY STORAGE
DEVICES
DEVICE CAPACITORS EDLC BATTERY
CHARGING TIME μ sec – m sec m sec - minute Hours
DISCHARGE TIME m sec – minute Minutes – months
μ sec – m sec
CYCLE LIFE 106 - 108 106 - 108 200-1000
SPECIFIC POWER > 10,000 1000-3000 <500
(W/KG)
SPECIFIC ENERGY <0.01 0.5-5 50-300
( Wh/KG)

6. TYPES OF SUPERCAPACITORS

7. 1.EC DOUBLE LAYER CAPACITORS
The term electrochemical double layer capacitor is most
commonly used for carbon based double layer capacitors
because of its high capacitance value.
It generally denotes the supercapacitor having non- faradaic
reactions at both electrodes

8. CARBON SUPERCAPACITOR

10. 2.PSUEDOCAPACITOR OR
ULTRACAPACITOR
In a pseudocapacitor, there are two basic reactions, which
lead to electrochemical cell.
Both occur at the interface between a conductor and an
electrolyte and both benefits form very high specific surface
areas at the electrode.
The first mechanism commonly referred to as charge
separation, which is well documented as non-faradaic
mechanism and is the basis for EDLC.
The second reaction commonly referred to as an oxidation –
reduction reaction due faradaic mechanism.

12. HYBRID CAPACITOR:
Hybrid power system is a new highly reliable
energy storage device. It is a combination of EDLC and a
battery. (eg. C and Li-ion). Hence it is known as capattery
(capacitor battery)

13. WHY “HYBRID”?
In supercapacitor two symmetric capacitors are connected
in series and the total capacitance is halved.
1/Ctotal = 1/C + 1/C
Ctotal = C/2.
But in a hybrid supercapacitor, one of the electrodes is
replaced by a battery electrode. So we can get the total
capacitance of the single capacitor electrode with the added
advantage of battery electrode.

14. Li-CARBON HYBRID SYSTEM

16. AIM
Development of hybrid power system combining various
power sources with the supercapacitors is the promising field
of research due to its fundamental advantages of both.
Our work focuses on developing a hybrid system combining
Li-ion battery and Carbon based supercapacitor.
We proposed to study the various supercapacitors based on
cathode material such as LiMn2O4, LiCoO2, LiFeP2O7 and
other such materials.

17. CATHODE MATERIAL
 Our work starts with making pure and doped lithium
manganate as suitable candidate for Lithium ion based
supercapacitor system
 Why Lithium manganate ?
Spinel LiMn2O4 is of great interest as a cathode
material for lithium ion batteries.
Advantage:
 High voltage, low cost and low toxicity
Disadvantage:
 Poor cycling behavior because of a fast capacity fading
due to Jahn Teller distortion

18. JAHN TELLER DISTORTION AND ITS
REMEDY
Average oxidation state of the manganese in
LiMn2O4 is 3.5 and thus any small perturbation
influencing the oxidation state may alter the ratio of Mn4+
and Mn3+.
When the ratio of Mn3+ increases ,it follows a
disproportionate reaction
2Mn3+ Mn4+ + Mn2+
and causes high solubility of spinel material into the
solution.

19. Remedy:
Wahihara suggest that partially substituted LiMxMn1-xO4
(M=Co, Cu, Ni, Mn) shows improved cyclability due to the
stronger M-O bonding of octahedron structure in
comparison to that of Mn-O bonding in LiMn2O4.
Hence we studied the both pure and the doped manganate
system

20. SYNTHESIS OF CATHODE MATERIAL
SOL-GEL PROCESS:
LiMn2O4 LiCo0.25Cu0.25Ni0.25Mn1.25O4
Li2CO3+MnCO3 in Acetic acid Li2CO3+MnCO3+CuCO3+CoCO3+
Stirring at 500C NiCO3.Ni(OH)3.1.5 H2O in Acetic acid
for 30 minutes
Addition of 50ml of EtOH
Heating at 800C
for 4 hours
Addition of Ammonia solution(30%)
Addition of 2 X Glycine
Heating until
gel formation
Filtering, Drying and Grinding
1.Heating at 5000C for 12 h
2.Firing at 6500C for 12 h
3.Calcining at 7500C for 12h
SEM
Physical characterization XRD
FTIR

21. SCANNING ELECTRON
MICROGRAPHS
LiMn2O4 LiCo0.25Cu0.25Ni0.25Mn1.25O4

22. X-RAY DIFFRACTION
2000
LiMn2o4:
1800
JCPDS# 35-0782
1600 B a= 9.412 A0, b= 8.233 A0 , c=
0
1400
4.1002A0, V= 317.73 A 3
1200
A.U.
1000
800 311 LiCo0.25Cu0.25Ni0.25Mn1.25O4:
111
600 400 A a= 8.162, b= 7.0844, c= 6.235 Å
400 0
511
440 V= 360.6 A 3
200 222 331
0
10 20 30 40 50 60 70 80
2
Fig.1. XRD patterns of (A) LiMn2O4 and (B) doped compound.

23. Pristine LiMn2O4 adopts a cubic Fd3m space group
The XRD data does not shows any structural distortion on
doping which is evident when the doping concentration
increases X<0.5

24. FTIR SPECTROGRAPHS
75
70 The 628cm-1 peak is associated with
65
the symmetric Mn-O stretching
60
Transmittance %
55
vibration of the MnO6 groups.
50
The peaks 558, 512 and 418cm-1 are
45 A
40
attributed to bending mode of CoO6
35 octahedral (558) and Ni2+-O
30 stretching mode (512&418),
B
25 respectively in the doped compound
20
structure.
15
10
1100 1000 900 800 700 600 500 400
Wave number, cm-1
Fig. 2 IR spectra of LiMn2O4 (A) and doped compound (B)

25. ANODE MATERIAL
CNF – Carbon Nano Foam
High surface area (1500 m2/g)
Low electrical resistance
No participation in faradaic reactions at the applied voltage
High capacity (100 - 200 F/g)
Unlike AC, CNF combine high surface area with high bulk
density to give large capacitance values

26. CELL FABRICATION
CONSTITUENTS:
POSITIVE ELECTRODE - LiMn2O4(80%)
CNF(15%)
NMP(5%)
NEGATIVE ELECTRODE - CNF(95%)
NMP(5%)
ELECTROLYTE - 1M LiClO4 in EC-PC
SEPARATOR - POLYPROPYLENE
CURRENT COLLECTOR - SS
ELECTRODE AREA - 1 cm2

27. GRINDING AND MIXING AFTER PASTING AND DRYING
COMPLETE SUPERCAPACITOR COMBINED ELECTRODES

28. ELECTROCHEMICAL CHARACTERIZATION
1. Electrochemical Impedance
spectroscopy
2. Cyclic voltammetry
3. Galvanostatic charge / Discharge

29. CYCLIC VOLTAMMETRY
FOR LiMn2O4: FOR LiCo0.25Cu0.25Ni0.25Mn1.25O4 :
Specific capacitance = Avg current/scan rate/weight of the
material
(F/g)
Scan rate
1 mV/s 2 mV/s 5 mV/s
Material
Pure 34 31 29
Doped 22 20 19

30. IMPEDANCE SPECTROSCOPY
9
8 Doped
7 Pure
6
5
R
Z''(Ohm)
4
w
3 C
2
1
0
-1
5 6 7 8 9 10 11 12 13
z'(Ohm)

31. Impedance parameters
PARAMETERS
RS (Ohm) Rct (Ohm) Cdl (mF/g)
MATERIAL
PURE 5.128 0.2917 2.98
DOPED 5.043 0.2394 3.14

32. CHARGE-DISCHARGE
DOPED
2.0 2.4 PURE
1.8
2.0
1.6
Voltage(V)
1.4 1.6
Voltage(V)
1.2
1.0 1.2
0.8
0.6
0.8
0.4
0.4
0.2
0.0
6300 6350 6400 6450 6500 6550 6600 6650
900 1000 1100 1200 1300 1400 1500 1600
Time(sec) Time (sec)

33. FORMULAE USED
Current x Discharge time
Specific Capacitance = Voltage x weight
Current x Voltage
Specific Power = weight
Current x Voltage x Discharge time
Specific Energy =
weight

34. RESULTS
PROPERTY SPECIFIC SPECIFIC SPECIFIC
CAPACITANCE POWER ENERGY
MATERIAL (F/g) (kW/kg) (kWh/kg)
LiMn2O4 15 200 20
LiCo0.25Cu0.25Ni0.25M
6 110 6
n1.25O4

35. FUTURE WORK
Finding the cycle life behavior of this capacitor and
variation of properties with cycle life.
Continuing the same work for the LiCoO2 cathode material
prepared by various methods and comparing their results
with the results of LiMn2O4.

36. THANK YOU

37. QUERIES ?