ORGANIC ELECTRODE MATERIALS AND
THEIR APPLICATIONS IN RECHARGEABLE
BATTERIES
Burak Esat1, Sümeyye Bahçeci1, Sevda Akay1, Muhammed Aydın2, Anton Momchilov3
1Fatih University Department of Chemistry, Istanbul/Turkey
2Gebze Institute of Technology, Gebze Kocaeli/Turkey
3 2Bulgarian Academy of Sciences
COST-EXIL
October 2015 in
Belek
Assoc. Prof. Burak ESAT
Fatih University, Department Of Chemistry
Istanbul-Turkey
Outline
Introduction
Early History-Conducting Polymers(CP)
Redox Polymers (RP)
Organo-sulphur Compounds
Carbonyl Compounds
Nitroxides
Others
Our Results
Nitroxide Based RPs as Cathodes
Anthraquinone (AQ) Based RPs
AQ- Functionalized Reduced Graphene Oxide (RGO)
Conclusions
Acknowledgements
History of Organic Batteries Based on
Organic Polymers as Electrodes
Synthesis and use of organic conjugated polymers as electrode materials started after the pioneering work of McDiarmid, Heeger and Shirakawa in mid-1970s
A. Moliton et al. ,Polym. Int. 53:1397–1412 (2004)
Conjugated Polymers Cont’d
Alan J. Heeger: Semiconducting and metallic polymers, Nobel Lecture 2000
Disadvantages:
- Low charge capacity of
battery due to low doping
levels attainable
- Low battery stability &
cycle-life
Redox Polymers
Redox Polymers are the polymers with non-conjugated backbones which have electro-active groups incorporated into their structures either as pendant groups or as a part of their backbone.
Advantages:
-Light-weight
-Flexible
-Moldable into different shapes &sizes
-Low T manufacturing
-High theoretical charge capacity
-High rate capability possible
-Good cycle performance possible
-Environmentally benign
Redox Polymers
Sulfur Based Materials
Carbonyl Based Materials
Organic Radical Based Materials-
Organic Radical Batteries Organic Radical Polymers (ORP) are polymers bearing stable
organic radicals as pendant groups.
An Organic Radical Battery (ORB) can be defined as a battery that
utilizes a polymeric material (pure or composite) with pendant redox
active organic radical in at least one of its electrodes.
Hiroyuki Nishide and Kenichi Oyaizu , Science 2008:
Vol. 319 no. 5864 pp. 737-738 DOI: 10.1126/science.1151831
ORB
Oyaizu K., Nishide H., Adv. Mater. 2009,21,2339
R- e
+ eRR
- e
+ e
p-type doping
n-type doping
A Totally Organic Radical Battery
Redox Activity of
Organic Radicals
Nitroxide Type Radicals
Suga T., Nishide H., Interface. Winter 2005, 32.
P- Type Organic Radical Polymers
Polyacrylate Polystyrene
Polyether Polynorbornene Polyisocyanate
Theoretical Capacity
(mAh/g)=
(n) 96500
______________________
3600 monomer (g/mol)
1000
Nishide H . et al.© 2009 IUPAC, Pure and Applied Chemistry 81, 1961–1970
N- Type Organic Radical Polymers
C C
C
Nishide H . et al.© 2009 IUPAC, Pure and Applied Chemistry 81, 1961–1970
Graphite Anode/ORP Cathode
Suga T., Nishide H., Interface. Winter 2005, 32.
The power output per battery with a charge capacity of
5mAh increased to 7kW/L (1.4 times the level of
conventional units
Some Organic Cathode -Active Redox
Polymers Synthesized by Our Group
CR 2016 Coin Type Batteries
Cathode Composite :
20-40% Polymer
50-70% Carbon
10% PVdF Binder
Specific EnergyCapacity=
275 mWh/g
Specific ChargeCapacity=
77 mAh/g
TheoreticalCharge
Capacity
= 91 mAh/g
Specific EnergyCapacity=
250 mWh/g
Specific ChargeCapacity=
70 mAh/g
TheoreticalCharge
Capacity
= 102.6 mAh/g
Specific EnergyCapacity=
175 mWh/g
Specific ChargeCapacity=
36 mAh/g
TheoreticalCharge
Capacity
= 91 mAh/g
Specific EnergyCapacity=
280 mWh/g
Specific ChargeCapacity=
80 mAh/g
TheoreticalCharge
Capacity
= 108.8 mAh/g
Malonyl Tempo Diester Substituted
Thiophene
Theoretical Capacity=
108.8 mAh/g
Theoretical Capacity =
(n) 96500
__________________
3600 monomer (g/mol)
1000
Aydin M., Esat B., Journal of Polymer Research, 2015 available on-line
Polymer & Composite Characterization
0.5 0.6 0.7 0.8 0.9 1.0 1.1
-12
-10
-8
-6
-4
-2
0
2
4
6
8
Cu
rren
t (
A)
Voltage (V)
Poliymer
Composite
-Polymer : Eox: 0.75V , Ered: 0.66V , -Composite : Eox: 0.79V , Ered: 0.65V .
PolymerSEM image
Composite(Polymer/Graphite/PVDF:20/70/10)
CompositeSEM image
2.5-3.8 V at 0.1 mA (~0.3C)
0 20 40 60 80 100
180
200
220
240
260
280
Sp
ecific
En
erg
y C
ap
acity (
mW
h/g
)
Cycle ID
Charge
Discharge
0 20 40 60 80 100
40
60
80
Sp
ecific
Ch
arg
e C
ap
acity (
mA
h/g
)Cycle ID
Charge
Discharge
0 20 40 60 80
2.4
2.6
2.8
3.0
3.2
3.4
3.6
3.8
4.0
Vo
lta
ge
(V
)
Specific Charge Capacity
Specific EnergyCapacity=
180 mWh/g
Specific ChargeCapacity=
55 mAh/g
PROBLEM: Capacity fading due to
polymer dissolution
0 20 40 60 80
2,9
3,0
3,1
3,2
3,3
3,4
3,5
3,6
3,7
3,8
Vo
ltag
e (V
)
Capacity (mAh/g)
0,2 C
0,5 C
1 C
2 C
4 C
3V—3.9V
0 2 4 6 8 10
260
280
300
320
340
360
380
Sp
ecific
En
erg
y C
ap
acity (
mW
h/g
)
Cycle ID
Charge
Discharge
5 mol% Thiophene added intopolymerization rxn mixture
to decrease solubility in electrolyte
Specific EnergyCapacity=
280 mWh/g
Specific ChargeCapacity=
80 mAh/g
0.2 C
0 10 20 30 40 50
75
80
85
90
95
100
105
Sp
ecific
Ch
arg
e C
ap
acity (
mA
h/g
)
Cycle ID
Charge
Discharge
Less soluble polymer= Smaller capacity fading
Anode Materials: Quinones
Synthesis
Anode Materials: Quinones
-1.6 -1.4 -1.2 -1.0 -0.8 -0.6
-8
-6
-4
-2
0
2
4
6
8
10
12
14
Cu
rre
nt (
A)
Voltage vs. Ag/Ag+
(V)
Scan Rate= 0.0005V/s
Vs Ag/AgCl
TheoreticalCharge
Capacity
= 160.3 mAh/g
Organic Electrolyte
Aqueous Electrolyte
AQ Functionalized Reduced Graphene
Oxide (RGO)
AQ Functionalized Reduced Graphene
Oxide (RGO)
Synthesis
Conductivity
RGO-AQ 50%: 657 S/m
RGO-AQ-AQ 200%: 517 S/m
RGO-AQ 500%: 316 S/m
(RGO-AQ 50% = AQ to RGO
Ratio =50% w/w during preparation)
RGO-AQ| 30% NaOH | NiOOH
Conclusions
We have proved that organic RPs (Redox Polymers) with pendant TEMPO radicals which are obtained via simple & efficient low T organic synthetic methods can be used as cathode-active materials.
The cathode materials initially showed charge capacities close to their theoretical capacities, but the capacity degraded over time in most of the cases possibly due to polymer dissolution or electrode material degradation
These problems may be solved by:
Appropriate electrolyte choice
Chemical crosslinking of polymer or covalent attachment of the polymer on carbon surface
Anthraquinone-bearig RPs can be used as anode-active materials although they show sluggish redox behavior in organic elecrolytes.
AQ group is shown to be a good candidate in anode materials in high-rate aqoueous batteries when used with conventional cathode materials such as NiOOH.
RGO functionalization with electro-active groups such as AQ and Nitroxide radicals is a good strategy which avoids the use of redundant polymeric backbones and is thus promising for increasing the capacity.
Acknowledgements
This research has been supported by
Fatih University (BAP P50021103_G)
TUBITAK (Project # 112T516 & 114Z295)
Thank you for your attention