Organic Ionic Plastic Crystals – Novel
Ionic Electrolytes For Alkali Metal
Electrodes
Patrick C. Howlett,
George W. Greene, Jennifer M. Pringle,
Michel Armand and Maria Forsyth
Energy Research Team
Prof. MARIA
FORSYTH
Australian
Laureate Fellow
PATRICK
HOWLETT
JENNY
PRINGLE
MICHEL
DOUG
TONY
MATTHIAS FANGFANG
HOLLENKAMP ARMAND MACFARLANE
HILDER
CHEN
(ADJUNCT) (ADJUNCT) (ADJUNCT)
PhD Students
YAJING
YAN
NAHID
IRANIPOUR
GAETAN
GIRARD
XINGYU
CHEN
CAMERON
POPE
YOGITA
OZA
Recently completed PhDs
FAEZAH
MAKHLOOGHIAZAD
YUNDONG
ZHOU
SHANNON
BIDDULPH
ROSSIE
RAO
AMINAH
NOOR
MEGA
HAMILTON
TAREKEGN
YARIMO
XIAOEN
WANG
CRISTINA
POZOGONZALO
NMR
(Waurn Ponds)
TRISTAN
SIMONS
LIYU
JIN
LUKE
O’DELL
DANIEL
GUNZELMANN
HAIJIN
ZHU
KONSTANTIN
ROMANENKO
Context:Needforcheap,reliableandsafeenergystorage
Metal/airbaLeries(Zinc,Magnesium,oxygenreducQon)
Sodium-ionbaLeries
LithiumBaLeries
SyntheQcEnergySystems(ACES)
§  FlowbaLeries
§  Aircathodes
§  ThermalEnergyHarvesQng
§  3DElectromaterials
§  Solid-StateElectrolytes
§ 
§ 
§ 
§ 
Ø  Developingmaterialsandelectrolytestocontrol
safety,reliabilityandmaximiseenergydensity
PrototypingFacilitytobeestablishedbymid2016
Draw-downelectrodecoater Blisterforming
Tabcut&weld
Bio-logicba:erytests
EmulateBa*eryprototypelineatArgonneNa4onalLaboratory
Slurrymixer
Pouchcasesealing
Degas&sealunit
Up-scaling of electrode
materials production
Nanostructured electrode materials
Finalpouchcell
Market Size & Growth Projections Show Significant Growth For
Advanced Batteries Over The Next 5-10 Years
$200B
Panasonic (auto + stationary
only)
Y27,800B*
Lux Research
$60B
CAGR = 26% p.a.
Navigant Research
$50B
USD Sales
$50B
CAGR = 8% p.a.
$40B
$30B
$55B
$32B
CAGR = 16% p.a.
$20B
$15
B
Sources: Lux Research 2015,
Navigant Research 2015,
Panasonic Corporation
presentation 2015
$10B
Y750B
2014
2015
2016
2017
2018
2019
2020
2021
2022
2023
2024
2025
* Bubble size is not to scale
Common Li-ion Modules And Balance-of-system Are Beginning
To Be Used To Address Both EV And Stationary Storage Markets
Tesla-Panasonic
Tesla Model S BEV
Tesla Powerwall
Panasonic Residential Storage
Daimler
Mercedes S550e PHEV
ACCUMotive
Residential Storage
ACCUMotive
Business Storage
•  Tesla-Panasonic and Daimler are building volume/scale and reducing cell and
system cost by standardising battery components and architecture across
products for both the EV and stationary storage markets
Safety Is Increasingly A Critical Parameter For Advanced Batteries As
More EV And Stationary Applications Are Commercialised
Fundamental Materials Research – Ionic Liquids,
Plastic Crystals, Ionomer Membranes
Research strength in electromaterials materials design and
characterisation
(Australian Laureate Fellowship and Australian Center of Excellence in
Electromaterials Science (ACES))
• 
• 
• 
Ionic Liquids – ‘liquid salts’ i.e., low melting point by design
Plastic Crystals – ‘plastic salts’ i.e., pliable, ‘soft’ salts
Ionomers – single ion conducting polymers
-
-
-
-
Advantages - Thermal & Chemical stability, non-volatile, -non-flammable
i.e., intrinsically safe & durable batteries based on ionic electrolytes
What are Organic Ionic Plastic
Crystals (OIPCs)?
Cation-Anion pairs – analogous to Ionic Liquids
ü  Solid at room temperature → High reliability
ü  Electrochemical and thermal stability →
Safe electrolytes
ü  Ease of processing (vs. ceramic electrolytes)
Ions have orientational or rotational
disorder
But… still maintain long range order crystalline
structure
But… ionic conductivity typically too low for device applications
Figure 6 SEM micrograph of single crystal slip planes in P13 BF4 at −189◦ C.
[21], although the limitations of this simplistic argument
Ø  in molecular crystals have been discussed with
respect the organic crystal, tetraoxane [47].
Polycrystalline slip offsets were also shown via direct
Ø 
micrographic
example to occur in the P1x N(CF3 SO2 )2
plastic crystal systems within individual grains of a bulk
sample. In this
Ø case (Fig. 7), slip has occurred along a
single slip direction; note that the slip terminates at the
grain boundaries which do not lose their coherency.
Ø 
These micrographs
allow the mechanism of vacancy
migration and role of grain boundaries to be considered
here. The higher
Ø  interfacial energy of grain boundaries
typically cause lattice imperfections (e.g., impurities,
vacancies) to preferentially segregate there, acting as
sinks (and in some cases even sources) for these defects
[48]. The direct microscopic imaging of slip planes
Ø  6 and [49]) in single and polycrystalline P13 BF4
(Fig.
specimens and the structural analogue P12 N(CF3 SO2 )2
(Fig. 2f) support
Ø  the hypothesis that there is a mechanism of vacancy coalescence (thermally or stress activated) to produce dislocations that lead to slip 3planes
occurring within the constraints of the grain boundaries
(termed sub-grain). The coalescence of vacancies, particularly in
Ø P13 BF4 is reinforced by recent positron an-
nihilation lifetime spectroscopy studies which showed
in vacancy
size with a concomitant decrease
Undergo one or a series anofincrease
phase
transformations
up to the melting point
in number, as the P13 BF4 sample was heated through
the phase II to I transition [50].1,2
These ultimately impart
on the system its plastic characteristics and this work
has suggested dislocations within the grain structure are
likely to be responsible. The presence of defect sites
which act as paths of rapid diffusion are further supported by Nuclear Magnetic Resonance (NMR) studies
in which a composite spectrum, constituting a broad
base, superimposed by a sharp narrow peak was observed [39]. On this basis, the diffusion associated with
sub-grain dislocations in this system may be of more
importance in controlling the observed transport properties such as ionic conductivity than the bulk or grain
boundary diffusion. It has been reported previously [51]
that the single mechanism of slip in molecular crystals
will create steric hindrance between adjacent molecules
at the slip boundary. A stabilisation of boundary configuration can only be accomplished by an accompanying rotational displacement about the molecular centre
[51]. This may indeed correlate with the proposed rotator phase mechanism for fast ion conduction in many
4
plastic crystals
[41, 49, 52–55].
In Fig. 8, we present ionic conductivity data for the
plastic crystal forming P11 BF4 and the non-plastic crystal P14 BF4. Clearly, the conductivity data for P11 BF4
Transport mechanism associated with;
disorder modes in matrix ions
formation of secondary phases
presence of structural defects
Conductivity can be enhanced;
Addition of ‘impurities’ – in
this case Li salt
Addition of nanoparticles
Figure 7 Ambient temperature SEM micrograph of polycrystalline slip
occurring in the structural analogue P12 N(CF3 SO2 )2 .
1. Jin, L. et al. J. Am. Chem. Soc. 2012, 134, 9688−9697.
2. Pringle, J. et al. J. Mater. Chem., 2010, 20, 2056–2062
3 . MacFarlane, D. R. et al., Nature (London) 1999, 402, 792.
3299
4- Shekibi et al., J. Phys. Chem. C 2007,
111, 11463-11468.
Figure 8 Temperature dependant ionic conductivity in P11 BF4 and
P14 BF4 .
Phosphonium OIPCs
Ø 
Ø 
N-based OIPCs (e.g. ammonium, pyrrolidinium) often have
Phase I at higher than ambient temperature
Phosphonium ILs possess higher thermal and
electrochemical stability than their ammonium counterparts
Liyu Jin
Variable Temperature Synchrotron XRD
Pure & 4 mol% P1444FSI
•  Phase III (0 °C) and Phase II (17 °C)
– large differences between pure
and doped samples
•  Suggests at least 2 phases present in
4 mol% sample at lower
temperatures (e.g. pure & lithium
enriched phases)
•  Phase I (30 °C) are very similar
•  Similarity of XRD patterns at 30 °C
suggests Li enriched phase has
melted – consistent with DSC
– Gel like solid in Phase I
Conductivity
Phase III & II – 3.5 order of
magnitude increase of σ with
Li addition
– Li enriched phase?
Amorphous phase?
4 mol% & 8 mol% similar σ
Phase I – likely existence of
liquid component percolating
at grain boundaries1 – lower
Ea - still exhibits soft-solid
character
W. A. Henderson, D. M. Seo, Q. Zhou, P. D. Boyle, J.-H. Shin, H. C. De Long, P. C. Trulove,
and S. Passerini, Adv. Energy Mater., 2012, 2, 1343–1350.
Li | LiFePO4 Cell Cycling at 30 °C
i.e. Phase I
•  50 cycles at 0.3C (1.5 – 2
mg.cm-2 cathode loading)
– 160 mAh.g-1
•  SEI formation in initial
cycling
•  Cell polarisation
decrease;
– ‘preconditioning’
process1
– melting at interface
•  Retained 130 mAh.g-1 at
1C
P. C. Howlett, Y. Shekibi, D. R. MacFarlane, and M. Forsyth, Adv. Eng. Mater., 2009, 11, 1044–1048.
Li | LiFePO4 Cell Cycling at 20 °C
i.e. Phase II
•  Reached 155 mAh.g-1 at 0.1 C
after the 10th cycle
•  Large decrease in interfacial
impedance with cycling – SEI
formation & preconditioning
•  Retained 118 mAh.g-1 at 1 C
OIPC Nanofibre Composites
OIPC%
solu*on%
in%
Acetone%
Cast%on%
nanofibres%
and%
evaporate%
Press%in%
plas*c%
phase%eg,%
80%°C%
Thin%&%
flexible%
composite%
Solvent or melt process results in
different morphology
a)
b)
~30 µm
Composite
surface
50 µm
c)
20 µm
d)
Thin and flexible solid-state organic ionic plastic crystal-polymer nanofibre composite
electrolytes for device applications.
P. C. Howlett, F. Ponzio, J. Fang, T. Lin, L. Jin, N.
~30 µm
Iranipour and J. Efthimiadis, PCCP, 2013, 15 (33) 13784.
Li | C2mpyrBF4 10 mol % LiBF4 PVdF | LiFePO4 Cell
Current rate : C/15 (nominal time for full discharge of capacity is 15hrs)
4.0
600
Initial
Cycled
400
0
Increasing cycles
Phase I
0
20
40
60
80
100 120 140 160
-
Capacity (mAh/g)
4.0
0
200
400
600
T = 50 °C
25
21
30
+
N
3.5
2000
H3C
1000
0
2.5
1.5
200
3000
5 8-10 20
2
3.0
2.0
Potential (V)
-Im(Z) (ohm)
4000
1
3.5
Potential (V)
•  Reduced interfacial impedance
with cycling - preconditioning
•  Approached theoretical capacity
after 10 cycles at 80 °C
•  Charge-discharge at 50 °C
T = 80 °C
0
1000
2000
3000
4000
Re(Z) (ohm)
OIPC conductivity @ 50 °C 3.3 ×
3.0
F
2.5
F
2.0
10-7
Scm-1.
1.5
CH3
Phase II
0
20
40
60
80
100 120 140 160
Capacity (mAh/g)
B
F
F
Thermal analysis & Conductivity
10% Li - C2mpyrBF4
+ PVdF
C2mpyrBF4 + PVdF
10% Li - C2mpyrBF4
C2mpyrBF4
N. Iranipour, D. J. Gunzelmann, A. Seeber, J. Vongsvivut, C. Doherty,
F. Ponzio, L. A. O'Dell, A. F. Hollenkamp, M. Forsyth, P. C. Howlett, J.
Mater. Chem., 2015, DOI: 10.1039/c4ta07155g
Nahid
Iranipour
7Li
Solid-state NMR
LiBF4 - C2mpyrBF4
LiBF4 - C2mpyrBF4-PVdF
T (°C)
70
343
333
60
323
313
50
303
283
40
273K
30
10
0
200
100
0
7Li (ppm)
-100
-200
200
100
0
7Li (ppm)
-100
-200
Synchrotron Powder XRD
•  2nd Li-rich phase evident in Phase II & IV – not evident in
composite
•  Li doped composite attains cubic structure in Phase II
•  Broader peak widths indicating smaller crystallite sizes or
higher lattice strain
•  PALS measurements indicate increased average free
volume size (pure OIPC)
Phase II (50 °C)
10% Li - C2mpyrBF4 + PVdF
10% Li - C2mpyrBF4
C2mpyrBF4
C2mpyrBF4 + PVdF
More ‘plastic’ systems…
Triethyl(methyl)phosphonium bis (fluorosulfonyl)imide
[P1222][FSI]
Triethyl(methyl)phosphonium bis(trifluoromethanesulfonyl)imide
[P1222][TFSI]
[P1222][FSI]
Li addition
Li plus fibres
[P1222][TFSI]
Can we avoid Li ‘trapping’?
Poly(diallylmethylammonium)TFSI
Poly(DADMA)
Prof David Mecerreyes
PIL(TFSI)-powder
PIL(TFSI)-electrospun fibers
1500
1000
wavenumber / cm
15 KV
20 KV
500
-1
25 KV
SUMMARY
Lithium batteries are expected to become the dominant
technology for for EV and stationary energy storage in the
coming decade
OIPCs possess ‘ideal’ properties for application as electrolytes
in high energy electrochemical devices
•  ‘Pre-conditioning’ is a key aspect in achieving good cell performance with
OIPCs
•  Stable cycling performance of (Li | LiFePO4) OIPC based demonstrated at
practical rates at 30 °C and 20 °C.
•  Flexible OIPC – electrospun polymer nanofibre composites with enhanced
transport and mechanical properties were described.
•  Functional nanofibres can modify OIPC phase nucleation and ion transport
properties
Acknowledgements
•  Prof Maria Forsyth
•  Dr Fangfang Chen
•  Mrs Nahid Iranipour
•  Dr Jian Fang
•  Prof. Michel Armand (Thinker in
Residence)
•  Prof. David Mecerreyes (Thinker in
Residence)
Australian Research Council
- 
Australian Centre of Excellence for
Electromaterials Science
- 
ARC Discovery Project
- 
APA award – Liyu Jin
•  Prof. D R MacFarlane