designing new polymeric electrolytes for lithium – ion battery applications

DeDesigning new signing new polymeric electrolytes polymeric electrolytes

for for Lithium Lithium – Ion – Ion Battery ApplicationsBattery Applications

Alistore ERI | www.alistore.eu

OutlineOutline

• Polymer electrolytes advantages and drawbacksPolymer electrolytes advantages and drawbacks

• Composite polymeric electrolytes: fillers and anion receptorsComposite polymeric electrolytes: fillers and anion receptors

• Role of salt anionsRole of salt anions

• New types of imidazole saltsNew types of imidazole salts

• ConclusionsConclusions

Copyrights Marek Marcinek

Li+

PEO

Polymer Electrolytes Polymer Electrolytes

• Electrodonor polymersElectrodonor polymers• O,N,S (sufficient donor ability for O,N,S (sufficient donor ability for

complexation)complexation)• Sufficient distance between sitesSufficient distance between sites• AmorphousAmorphous• Polyethers - good candidatesPolyethers - good candidates• Low Tg (flexibility)Low Tg (flexibility)

General classification General classification Polymer ComplexesPolymer ComplexesPolymer GelsPolymer GelsPolyelectrolytes (Single Ion Conductors)Polyelectrolytes (Single Ion Conductors)

•nonvolatility,•no decomposition at the electrodes,•no possibility of leaks,•use of metallic lithium in secondary cells (lithium dendrites growing on

the electrode surface would be stopped by the non-porous and solid electrolyte),

•lowering the cell price (PEO is cheaper than organic carbonates; it could be used as a binder for electrodes to improve the compatibility of consecutive layers; moreover fabrication of such a cell would be easier –cost),

•strengthening of cells thanks to the all-solid-state construction,•shape flexibility,•lowering the cell weight – non-volatile, all-solid-state cells don’t need

heavy steel casing,•improved shock resistance,•better overheat and overcharge allowance,•improved safety!!!

Solid Polymer Electrolytes AdvantagesSolid Polymer Electrolytes Advantages

low cationic transference number (close to 0.1-0.3) of most conventional P(EO)-LiX polymer electrolytes,

forming of highly resistive layers at the anode-electrolyte interface,

high degree of crystallinity of PEO based electrolytes,

conductivity at ambient temperature not high enough for application in batteries.

Limitations of polymeric Limitations of polymeric electrolyteselectrolytes

Three component systems:Three component systems:

Composite electrolytes

polymer

Lithium salt

filler able to impact ion-ion and ion-polymer interaction

PEO-DME - (Mw=500) dicapped with methyl groups(Mw=500) dicapped with methyl groups

LiClOLiClO44, LiNTFSi, LiCF, LiNTFSi, LiCF33SOSO33, LiI, LiBF, LiI, LiBF44

•Ceramic fillers•TriphenylboraneTriphenylborane•CalixareneCalixarene•Calix[6]pyrolleCalix[6]pyrolle

ConductivityConductivity

PEGME-LiClO4

PEGME-LiClO4 -Al2O3neutral

PEGME-LiClO4 -Al2O3basidic

PEGME-LiClO4 -Al2O3acidic c / mol kg-1

10-5 10-4 10-3 10-2 10-1 100

log

/ S

cm

-1

-7

-6

-5

-4

-3

Viscosity as a function of salt Viscosity as a function of salt concentrationconcentration

c / mol kg-1

10-6 10-5 10-4 10-3 10-2 10-1 100 101

/ P

a s

0.1

1

10

100

PEGME-LiClO4

PEGME-LiClO4 -Al2O3neutral

PEGME-LiClO4 -Al2O3basidic

PEGME-LiClO4 -Al2O3acidic

…and temperature

temperatura/ oC

0 20 40 60 80 100

lepk

oϾ/

Pa

s0,1

1

10

100

PEGME-LiClO4 3 mol kg -1

PEGME-LiClO4-Al2O3 kw. 3 mol kg -1

PEGME-LiClO4-Al2O3 oboj. 3 mol kg -1

PEGME-LiClO4-Al2O3 zas. 3 mol kg -1

PEODME-LiClO4 3 mol kg -1

PEODME-LiClO4-Al2O3 kw. 3 mol kg -1

PEODME-LiClO4-Al2O3 oboj. 3 mol kg -1

PEODME-LiClO4 4 mol kg -1

PEODME-LiClO4-Al2O3 oboj. 4 mol kg -1

Fuoss-KrausFuoss-Kraus

PEGME-LiClO4

PEGME-LiClO4 -Al2O3 neutral

PEGME-LiClO4 -Al2O3 basidic

PEGME-LiClO4 -Al2O3 acidic

c / mol kg-1

10-6 10-5 10-4 10-3 10-2 10-1 100 101

% p

ar j

onow

ych

0

20

40

60

80

100

0

20

40

60

80

100

1e-4 1e-3 1e-2 1e-1 1e+015

20

25

30

35

C / mol * kg-1

T /

oC

% of free ions in PEO-DME neutral system as a function of temperature

0 %20 %40 %60 %80 %100 % 0

20

40

60

80

100

1e-5

1e-4

1e-31e-2

1e-11e+0

15

20

25

30

35

% o

f ion

pai

rs

% of ion pairs in PEO-DME neutral system as a function of temperature

0 %20 %40 %60 %80 %100 %

0

20

40

60

80

100

1e-4 1e-3 1e-2 1e-1 1e+015

20

25

30

35

% of ions triplets in PEO-DME neutral system as a function of temperature

0 %20 %40 %60 %80 %100 %

Changes of the interface resistance in time

Lithium transference numbers for (PEO)20LiClO4 based composite electrolytes containing 10% by weight of inorganic filler additivesType of the electrolyte

Type of the filler Temperature/oC Lithium transference number

(PEO)20LiClO4 Filler free sample 40 0.31

(PEO)20LiClO4 Al2O3 40 0.61

(PEO)20LiClO4 Al2O3 (1% ASG) 40 0.66

(PEO)20LiClO4 Al2O3 (4% ASG) 40 0.72

(PEO)20LiClO4 Al2O3 (8% ASG) 40 0.77

(PEO)20LiBF4 0 70 0.32

(PEO)20LiBF4 Surface modified ZrO2 70 0.81

PEO-based electrolytes transference numberPEO-based electrolytes transference number

CC7272HH9696NN44OO66

MW=1113.56 gr/moleMW=1113.56 gr/mole

Calixarene 1

CC7272HH9494NN66OO1010

MW=1203.55 gr/moleMW=1203.55 gr/mole

Calixarene 2

CC6868HH104104NN44OO66

MW=1073.58 gr/moleMW=1073.58 gr/mole

Calixarene 3

Calix[6]pyrrole

CC7272HH6666NN66

MW= MW= 1014.52 1014.52 gr/molegr/mole

Supramolecular compoundsSupramolecular compounds

Polymer Type Temp (o

C)t+

LiI:PEO7 55 0.51

LiI:PEO7 75 0.56

LiI:PEO7 90 0.51

LiI:P(EO)7 (Calix.2) 0.3 75 0.74

LiI:P(EO)7 (Calix.2) 0.3 90 0.69

LiI:P(EO)7 (Calix.1) 0.3 75 0.35

LiI:P(EO)7 (Calix.1) 0.3 90 0.24

LiI:P(EO)7 (Calix.3) 0.3 75 0.70

LiI:P(EO)7 (Calix.3) 0.3 90 0.33

LiI:PEO20 55 0.35

LiI:P(EO)20 (Calix.2) 1 50 1

LiI:P(EO)20 (Calix.2) 1 75 0.93

LiI:P(EO)20 (Calix.2) 1 90 0.80

LiI:P(EO)20 (Calix.2) 0.3 50 0.51

LiI:P(EO)20 (Calix.1) 0.3 55 0.48

LiI:P(EO)20 (Calix.1) 1 55 0.45

LiI:P(EO)100 90 0.14

LiI:P(EO)100(Calix.1)0.25 90 0.15

LiI:P(EO)100(Calix.1)0.5 90 0.18

Experiment time - 60 minutes, applied voltage 0.01Volt.

Lithium transferrence numbers Lithium transferrence numbers tt++ for for LiI:PEOLiI:PEO77 and and LiI:PEOLiI:PEO2020

Conductivity of the system P(EO)10(LiI)1(Calixarene)x

2,6 2,8 3,0 3,2 3,4 3,6 3,810-11

10-10

10-9

10-8

10-7

10-6

10-5

10-4

10-3 Calixarene 1

tota

l / S

cm -

1

1000T -1 / K -1

x = 0 x = 0.1 x = 0.2 x = 0.4 x = 0.6 x = 0.8

110 100 90 80 70 60 50 40 30 20 10 0

t / °C

Temperature dependence of the bulk conductivity and interphase resistance RSEI of

the LiTf:P(EO)20 and LiTf:P(EO)20(C6P)0.5 Electrolytes

RSEI

Bulk conductivity

Lithium transference numbers for PEO-LiX-Calix-6-pyrrole electrolytes

Type of the electrolyte

Molar fraction of calix-6-pyrrole

Temperature/oC Lithium transference

number

(PEO)20LiI 0 70 0.25

(PEO)20LiI 0.125 70 0.56

(PEO)20LiI 0.25 70 0.75

(PEO)20LiI 0.5 70 0.78

(PEO)20LiBF4 0 70 0.32

(PEO)20LiBF4 0.125 70 0.78

(PEO)20LiBF4 0.25 70 0.81

(PEO)20LiBF4 0.5 70 0.85

(PEO)20LiCF3SO3 0 75 0.45

(PEO)20LiCF3SO3 0.5 70 0.76

Self-diffusion coefficients D and t+ at 363 K

Dpolymer10-8 cm2/s

D-

10-8 cm2/s

D+

10-8 cm2/s

t+

PEO-LiBF4-calixpyrrole

6.51 27.5 24.6 0.47

PEO-LiBF4 3.37 36.1 20.0 0.36

How does it (probably) work?

O OO

O

O

ClO4- Li+

Li+ClO4

-

ClO4-

Li+

Calix

CalixCalix

O

KI>Kcal>KT KI>KT>Kcal Kcal>KI>KT

KI-ion pairs formation constantKT-ionic tiplets formationKcal-calix-anion complex constant

Ion pairs (KA) and Ionic Triplets (KT) formation constans calculated for PEO-LiX (X=I-, CF3SO3

-) electrolytes

SaltKA KT

LiI 3,87x104 130

LiCF3SO3 3,18x104 72

LiBF4 1.75x105 77.69Kcal6-anion=27x103

Cyclic voltammograms of LiTf:PEO20 membranes with and without C6P and SiO2 additives at (a)75˚C and (b)90˚C over potential range

of 0-5.0V using SS/PE/SS cell configurationH. Mazor, D. Golodnitsky, E. Peled, W. Wieczorek, B. Scrosati, J.Power Sources, 178 (2008) 736-743

PEO-based electrolytes additives stabilityPEO-based electrolytes additives stability

Inhibition of crystallization

New Types of Ceramic Composites New Types of Ceramic Composites 1/2 – Concept and Structure 1/2 – Concept and Structure

New Types of Ceramic Composites New Types of Ceramic Composites 2/2 – Preliminary/First!!! 2/2 – Preliminary/First!!!

Electrochemical Testing Electrochemical Testing

Anions:

• are an important part of SEI build-upat +/- electrodes

• Control transport numbers t+ /t-

• Control dissociation and conductivity

• Control aluminium corrosion

AsF6-

BF4-

PF6- SbF6

-

ClO4-

Classics…Classics…

Tendency to decompose according to equilibrium:LiBF4 BF3 + <LiF>

LiPF6 PF5 + <LiF>Fast reaction above 80°C

Destruction of electrolyte and interfaces

Explosive ! Toxic !

Conceptual approach to anion design

“N, C” are favorable:

Weak interactions Li—N but easy oxidation

“O” is not a favorable building block:

Strong Li—O interactions ion pairing, ≠ ClO4-, BOB-

If O present, F or CnF2n+1 is required

Stability Domains

Li4Ti5PO12

LiV3O8

LiMnPO4

LiFePO4

LiCoPO4

Li metal

LiMO2 mixed oxides

Graphite

Fluorinated anions

Non fluorinated anions

Diagonally Diagonally OOpposed pposed IInterests?nterests?

+ -

Enhance the activity of anions (SN)

Li+

Organic chemistry Electrochemistry

Maximize the conductivity

Ionic processes +-

-

- I- = 2,2 Å design of polyatomic

anions

Hückel anions…

X = N, C-CN, CRF, S(O)RF

See P. Johansson et alPhysical Chemistry Chemical Physics, volume 6, issue 5, (2004).

Aromaticity 4n + 2 «  » electrons

pKA = 10-60 pKA = 10-20

Gain of > 1 eV by resonance

LiDCTA

NN

N

CNNC

-

DCTA

Stable to 3.8 V (La Sapienza, KZ) inexpensive

NH2H2N

CNNC

ON

O-

NC CN

NN

N--2H2O

Gives quite fluid ILs N

NC CN

NN

N-

Most Stable Lithium Imidazole Configurations

LiTDI LiPDI

B3LYP/6-311+G(d)Scheers et al. 2009

1.88 Å 1.87 Å

1.92 Å

1.93 Å

LiTDI < LiPDI < LiDCTA < LiTFSI < LiPF6

Gas Phase Ion Pair Dissociation Energies

Ion pair (g) Li+ (g) + Anion- (g)

MP2/6-31G(d)

LiTDI LiPDI LiDCTA LiTFSI LiPF6 Scheers et al. 2009

LiTDI (2-trifluoromethyl-4,5-LiTDI (2-trifluoromethyl-4,5-dicyanoimidazole lithium salt)dicyanoimidazole lithium salt)

C

CN

C

N-

CF3

C

C

N

N

Li+

d io x a n e / T

+ L i2 C O 3 / w a te r

C NH2

NH2CN

N O

C

O

C

O

CF3

CF3

+

- Easy, low‑demanding, inexpensive, one‑step, high yield syntheses;

- Salts are pure, stable in air atmosphere, non‑hygroscopic, stable up to 250°C, easy to handle;

New saltsNew salts

- NN

CF3

N N

- NN

C2F5

N N

- NN

n-C3F7

N N

-

N

NN

N

CF3

Li+

Li+

Li+

Li+

LiTDI LiPDI LiHDI

LiTPI

Conductivity in PEO

2.5 2.6 2.7 2.8 2.9 3.0 3.1 3.2 3.3 3.4 3.51E-8

1E-7

1E-6

1E-5

1E-4

1E-3

0.01

cond

uctiv

ity / -1

cm-1

1000/T / K-1

DCTA PDI TDI

SS / PEO20LiX / SS

cooling scan

LiDCTALiPDILiTDI

N

NN

NC CN

Li+

2.4 2.6 2.8 3.0 3.2 3.4 3.61E-8

1E-7

1E-6

1E-5

1E-4

1E-3

0.01

T/°C2139,460,184

C

ondu

cibi

lità

/ S

cm-1

x: 10%

1000T-1 / K-1

111,5

x: 0%

PEO20LiCF3SO3+ ZrO2SACasting

PEO20LiDCTAHot-Pressing

2.4 2.6 2.8 3.0 3.2 3.4 3.61E-8

1E-7

1E-6

1E-5

1E-4

1E-3

0.0121

T / °C39,460,184111,5

Cond

ucib

ilità

/ Sc

m-1

1000T-1 / K-1

PEO20

LiBOB

PEO20

LiBF4

PEO20LiBOB/ LiBF4

Hot-Pressing

2.4 2.6 2.8 3.0 3.2 3.4 3.61E-8

1E-7

1E-6

1E-5

1E-4

1E-3

0.0121

T / °C39,460,184111,5

Con

duci

bilit

à / S

cm-1

1000T-1 / K-1

PEO20

LiDCTA

PEO20

LiBF4

2.6 2.8 3.0 3.21E-6

1E-5

1E-4

1E-3

0.01

Conduct

ivity

S

/ cm

1000 / T K-1

PEO 20

A

PEO 20

B

PEO20LiTDIPEO20LiPDI

Hot-PressingPEO20LiTDIPEO20LiPDI

3.0 3.5 4.0 4.5 5.0 5.5 6.0 6.5

0.00

0.05

0.10

0.15

0.20

curr

ent /

mA

/cm

2

Potential / V

DCTA PDI TDI

Li / PEO20LiX / Super P

Anodic breakdown voltage vs. Li

P(EO)20LiDCTA 3.6V

P(EO)20LiPDI 4.0V

P(EO)20LiTDI 4.0V

Anodic stability

LiDCTALiPDILiTDI

0 40 80 120 160 2000

-20

-40

-60

-80

-100

Zim

m /

Ohm

Zreal / Ohm

2h 4.5h 7h 1d 2d 5d 7d 12d

0 40 80 120 160 2000

-20

-40

-60

-80

-100

Zim

m /

Ohm

Zreal / Ohm

2h 4.5h 7h 1d 2d 5d 7d 12d

0 40 80 120 160 2000

-20

-40

-60

-80

-100

Zim

m /

Ohm

Zreal / Ohm

2h 4.5h 7h 1d 2d 5d 7d 12d

LiPDI

LiTDILiDCTA

Li / PEO20LiX / Li

Interphase resistance - PEO

0 3 6 9 12 150

40

80

120

160

200

240

resi

stan

ce /

Ohm

time / d

PDIa PDIb TDIa TDIb DCTAa DCTAb

Interphase resistance - PEOLi / PEO20LiX / Li

LiPDIaLiPDIbLiTDIaLiTDIbLiDCTAaLiDCTAb

Cycling behaviour

Rate capability (PEO)

% o

f ca

paci

ty a

t C

/20

Rate capability (PEO)

% o

f ca

paci

ty a

t C

/20

Research team working on new saltsResearch team working on new salts

Presentation of research teamworking on new lithium salts:

Warsaw University of Technology: - L. NiedzickiL. Niedzicki, J. Syzdek J. Syzdek and W. WieczorekW. Wieczorek – characterization of salts and low molecular weight polyether electrolytes- J. PrejznerJ. Prejzner, P. SzczecińskiP. Szczeciński, M. BukowskaM. Bukowska - synthesis of new salts- A. Błażejczyk, M. KalitaA. Błażejczyk, M. Kalita – synthesis of anion receptors- Z. ŻukowskaZ. Żukowska M. Marcinek M. Marcinek – spectroscopic studies

Universite de Picardie Jules Verne, Laboratoire de Reactivite et de Chimie des Solides- S. GrugeonS. Grugeon, S. LaruelleS. Laruelle - characterization of solid polymeric electrolytes, studies of electrochemical stability and battery performance- and M. ArmandM. Armand – development of new salt systems

Faculty of Chemistry, University of Rome, “ La Sapienza- S. PaneroS. Panero, P. RealeP. Reale and B. ScrosatiB. Scrosati, - characterization of solid polymeric electrolytes; conductivity, transference numbers and electrochemical stability

Department of Applied Physics, Chalmers University of Technology, - J. ScheersJ. Scheers, P. JohanssonP. Johansson, P. JacobssonP. Jacobsson – modeling and spectroscopic studies