Polymerized Ionic Liquid Block Copolymers As Solid-State Polymer Electrolytes for
Lithium-Ion Batteries
Jacob R. Nykaza1, Yossef A. Elabd2
1Drexel University, Department of Chemical & Biological Engineering, Philadelphia PA 19104, U.S.A.
2Texas A & M University, Artie McFerrin Department of Chemical Engineering, College Station, TX 77843, U.S.A.
Lithium-Ion Batteries
Polymer Synthesis: Reversible Addition Fragmentation
chain Transfer (RAFT) Polymerization
Characterization: Conductivity & Morphology
Ionic Conductivity
PIL Block Copolymer: poly(MMA-b-MUBIm-Br)1
NC
O
]m
CH3
(2)
n
(3)
Ratio
n
O
O
O
( )11
O
O
( )11
Br
O
MMA
O
O
O
O
m
EMImTFSI
N
Br
PMMA Macro-CTA
N
(1) CTA, THF, 70 °C, 5 h
(2) 11-BrUMA, THF, 70 °C, 6 h
(3) 1-butylimidazole, DMF, 70 °C, 72 h
p(MMA-b-MUBIm-Br)
• Nonflammable
• Lightweight
• Flexible
0.0
• Low Capacity
m
O
Polymerized Ionic Liquid (PIL) Block
Copolymers
]
][
[
[
n
m
O
O
]
][
(4)
O
O
( )11
[
n
m
O
O
(5)
O
( )11
2.6
3.6
0
20
40
60
80
100
120
T- T (K)
g
EIS: 4-electrode in-plane method, Solartron, 1260 impedance analyzer, 1287 electrochemical interface, Zplot software
Small Angle X-Ray Scattering
TFSI
N
poly(MMA-b-MUBIm-TFSI)
Ratio = 0.5
poly(MMA-b-MUBIm-TFSI)
Ratio
p(MMA-b-MUBIm-Br)
p(MMA-b-MUBIm-TFSI)
(4) 0.1 M LiTFSI, DI H2O, 23 °C, 24 h
(5) Various IL mixture ratios
Block Copolymer
• Self-assembled nanostructures
• Tunable morphology and domain size
• 3-D nano-ion conducting channels
p(MMA-b-MUBIm-TFSI)
+ IL mixture
Note: 18 mol % MUBIm-TFSI determined by
1H
NMR
𝐼𝐿 𝑚𝑖𝑥𝑡𝑢𝑟𝑒 [𝑚𝑜𝑙 𝐼𝑚+ 𝑇𝐹𝑆𝐼− ]
𝑅𝑎𝑡𝑖𝑜 =
𝑃𝑜𝑙𝑦 𝑀𝑀𝐴 − 𝑏 − 𝑀𝑈𝐵𝐼𝑚 − 𝑇𝐹𝑆𝐼 [𝑚𝑜𝑙 𝐼𝑚+ 𝑇𝐹𝑆𝐼− ]
0.5
0.4
0.3
0.2
Temp.
120 °C
0.1
• Ratio ranged from 0.0 (no IL mixture) to 0.5.
• Values over 0.5 provided unstable free standing films.
• Synthesize PIL block copolymer using RAFT polymerization
• Study impact of incorporation of ionic liquid (IL) mixture
• Develop highly conductive solid-state polymer electrolytes for Lithium-ion
Polymer Batteries
30 °C
Characterization: Glass Transition Temperature (Tg)
0.1
Ratio
0.0
Br
(CH2)9
Br
11-BrUMA
126 °C
39.1 °C
0.1
15.2 °C
0.3
OO
N
F
poly(MMA-b-MUBIm-TFSI),
Ratio = 0.0
N
O
S
F
F
OO
S
F
F
N
F
F
N
0.2
14.3 °C
IL mixture = 1 M LiTFSI/EMImTFSI
O
• Synthesized novel polymerized ionic liquid (PIL) block copolymer by ion exchange and addition of IL
mixture.
• Anion exchange to TFSI- from Br- anion resulting in only one Tg that decreases with addition of IL
mixture.
• Conductivity increases ~2 orders of magnitude with increasing amount of IL mixture that is
predominately due to increase in charge density.
• SAXS shows disordered morphology that does not change over temperature range studied.
• Attractive material for polymer electrolyte in lithium ion batteries.
13.7 °C
EMImTFSI
0.4
10.1 °C
F
-100
F
References
(1) Nykaza, J. R.; Ye, Y.; Elabd, Y. A. Polymer 2014, 55, 3360.
0.5
O
S
F
-50
0
50
100
Temperature (°C)
150
Conclusions
25.9 °C
Heat Flow (a.u.)
23 °C
Heat Flow (a.u.)
O
LiTFSI
q (nm )
39.1 °C
O
(1) triethylamine, DCM, 25 °C, 18 h
-1
SAXS: Rigaku S-MAX 3000, through-plane, Linkam High Temperature Control Stage
(1)
Cl
1
poly(MMA-b-MUBIm-TFSI)
poly(MMA-b-MUBIm-Br), Ratio = 0.0
(CH2)9
0.1
q (nm )
OH
+
1
Under Vacuum
-1
11-bromoundecyl methacrylate
O
0.0
30 °C; Under Vacuum
Synthesis: IL Monomer & IL mixture
F
3.4
EMIm TFSI
Objectives
S
3.2
1000/T (K )
Li TFSI
PIL block copolymers as solid-state membranes for lithium-ion polymer batteries
are of particular interest due to the following unique properties:
F
3
-1
N
Polymerized ionic liquid (PIL) block copolymers have recently been synthesized
and are of interest for energy conversion and storage devices such as fuel cells,
batteries, super capacitors, and solar cells.
O
2.8
-9
poly(MMA-b-MUBIm-TFSI)
O
( )11
O
N
N
Dry
poly(MMA-b-MUBIm-TFSI)
O
O
TFSI
Br
-8
n
N
N
-7
0.2
0.1
]
][
-6
0.3
-10
2.4
PIL Block Copolymer: poly(MMA-b-MUBIm-TFSI)
-5
Intensity (a.u.)
• Safety Concerns with
Flammability of Liquid
Electrolyte
• High conductivity and chemical stability
• Wide electrochemical window
• Tunable physical properties
-6
Dry
Future Challenge
+
0.5
-8
Ion Exchange & IL mixture addition
Critical Drawback
Polymerized Ionic Liquid
-4
Intensity (a.u.)
• High Energy Density
• High Cycle Lifetime
• Low Maintenance
-4
0.4
Solution: Polymer Electrolyte
Liquid Electrolyte
0.0
0.1
0.2
0.3
0.4
0.5
-3
-2
p(MMA-b-BrUMA)
Image reference: Bruce, P. G.; Solid State Ionics 2008,179,752-760
-2
log (S cm-1)
O
[
HO
m
]
][
[
-1
(1)
S
]
][
[
O
log  (S cm )
S
0
-80
-40
0
40
80
120
160
200
Acknowledgement
Temperature (°C)
Li
NTI 1001-037
DSC: TA instruments, Q200, 10 ºC/min, N2 gas, second heating cycle.
W911NF-07-1-0452