Advanced material selection for Li-ion solutions.pdf · © Dow 2010 All rights reserved June 2010 Advanced material selection for Li-ion Dow Chemical [email protected]

© Dow 2010 All rights reserved June 2010

Advanced materialselection for Li-ion

Dow Chemical

[email protected]


COSTSAFETY

LIFE

Industry demands the performance of Li-ion

Material barriers preventLi-ion enabling industrial apps

BUTLi-ion dominates consumer

portable applications

MaterialBarrier

Consumer Apps Industrial Applications

New materials are essential to bring the benefits of Li-ionto industrial and Automotive applications

“To make a leap forwards with hybrids,we’ll need a new battery technology”.

- D. Hermance, Toyota .

1-3 3-5 20-50 50-90 30-100 100-300 250-1000 2000

Wh (capacity)

Phone PDA LaptopPowertools eBike UPS HEVMedic pHEV

15000


Dow applies unique competences to enableLithium Ion batteries and applications

ManufacturingPolymer films (packaging)

FilmTec membranes (water purification)World-class cellulose ethersLargest global latex supplier

High purity solventsSix-Sigma

ChemistryInorganic chemistryOrganic ChemistrySB latex chemistry

Cellulose ether-based materialsSmall molecule synthesis

Electrochemistry

Dow is a leading automotive supplier and provides capability andcredibility in building Li-ion business for P-H-EV

Material SciencePolymer film technologyPolymer material science

Polymer processing /rheologyHigh through-put R&D

Transport scienceModeling


Dow’s Objective: to enable Li-Ion applications

• Apply Dow’s long history of materials innovation into emerging

automotive P-H-EV and other Lithium-ion applicationsincluding power tools and e-bike

• Develop advantaged materials, that create value for ourpartners & customers

• Develop strategic mutually beneficial partnerships to developnext generation Li-ion components

• Provide unparallel service and support to our customers andpartners that enables them to capture significant market share

The Dow Chemical Company seeks to become apreferred supplier of superior materials to

lithium-ion battery manufacturers


Dow’s Developmental Separator:High Thermal Dimensional Stability

Early stage developmental separator

• Minimal shrink after aging 1hr at 225ºC• excellent thermal dimensional stability vs polyolefin separators

Dow Separator225ºC for 1 hour

(no shrink at 125ºC)

Before

After


Dow Electrolyte A – Developmental ProductDow is developing differentiated carbonate-based electrolyte using

novel additives that will lead to improved safety through lower flammability

Electrolyte PropertiesCarbonateBaseline

DowElectrolyte A

Decomposition Temp.

(Safety)180 ºC ~240 ºC

Conductivity (@25 °C)

(Power/Energy Density)10 mS/ cm 9 mS/ cm

Oxidative Stability

(High V. Cathodes)4.5 V 4.5 V

Temperature Range

(Operating capability)-20 to +50 ºC -20 to +50 ºC

• Increased decomposition temperature (~ 60ºC higher)

• Excellent performance (results indicate increased capacity)

• R&D efforts to further increase conductivity and temperature range


Dow Electrolyte A improves

thermal stability

•Enables safer batteries

•Thermal decompositiontemperature increased

•Heat flow significantly reduced =lower heat generation duringthermal decomposition

Dow Electrolyte A demonstrates

improved performance (button cell)

• Increased capacity (~25% increaseat 3V) vs carbonate controlwithout additive

• Validation is in progress

(large format cells)

4C Discharge Curves

1M LiPF6 in EC/DEC 1:1 v/v

2

2.5

3

3.5

4

4.5

0 20 40 60 80 100

Specific Capacity (mAh/g)

Vo

ltag

e(V

)

Carbonate Control

Dow Electrolyte A

Thermal Stability Comparison

Control: 1M LiPF6 in 1:1 EC/DEC

-1

0

1

2

0 50 100 150 200 250 300

Temperature (C)

Heat

Flo

w(W

/g)

Carbonate control

Dow Electrolyte A

Electrolyte A: Performance Data


Dow’s Commercially Available Binders:SBR Latex & CMC (Carboxy Methyl Cellulose)

Degree of Substitution (d.s.) = 1

Dow is the only company offering both Latex and Cellulose Ethers

• Ideal for nano structured anodes

• Water based processing

© Dow 2010 All rights reserved June 2010 9

2003 2005 2006 200920082007

R&DPatents

Up scale

Full cell

Demoapps

First demonstrator cells Proven in 100 kg scale

Dow cathode story: from Nano to MacroFrom Idea to Application


A new cathode: Why Phosphate ?Advantage of phosphates:• Low cost• Over-charge & under-charge resilient (1 Li)• Excellent structural stability (strong bond P-O)

- Good cycle life- Thermally and chemically stable- Safe

Phosphate choice:• Iron too low V 3.6 V vs. Li• Cobalt too high V 4.8 V vs. Li• Nickel too high V 5.1 V vs. Li• Manganese ideal V 4.1 V vs. Li

DOW combine benefits of a Phosphate and voltage of an Oxide

PLi

Mn

Durable Power Safe, V, low cost ($/kg)

High EnergyLow cost ($/Wh)

Nanostructured Li Mn PO4 =


Challenges of Phosphates, LiMnPO4

2.5 3.0 3.5 4.0 4.5-0.0003

-0.0002

-0.0001

0.0000

0.0001

0.0002

0.0003

3.48 V

3.6 V

3.9 V

4.22 V

I/A

cm

-2)

E / V vs. Li/Li+

Scan rate 25 V s-1

Temp. = 30oC

• LiMnPO4 is even less conductive than LiFePO4 : more polarisation- Carbon coating technology is more critical

• LiMnPO4 has double lattice mismatch than LiFePO4- Smaller domain and particle size necessary

• Low material density for phosphates: LiCoO2: 5.5, LiFePO4: 3.7, LiMnPO4: 3.4 g/cm3

• Sensitivity of Fe to air and moisture

• Sensitivity of anode to Fe and Mn

Challenge: electronic conductivity *

* C. Delacourt et al. Solid state ionics 117 (2006) 333C. Delacourt et al. J. Electrochem. Soc 152 (2005) A913

Challenge: Impedance

Phosphates have low density, and conductivity:Mn Phosphate is even more challenging!


LiMnPO4 electrochemical performance

Charge C+CV – Discharge C/10

Dow show world best performance and stability for LiMnPO4

Performance

Charging condition: CCCV 2.7 - 4.4V vs. LiDischarge: C rate calculated from 150mAh/gElectrode: C-LiMnPO4 2% carbon, 7.5% PVDF

Total carbon in electrode 20%Electrode thickness: 53 micronLoading (AM): 5.42 mg/cm2

Electrolyte: 1 M LiPF6 EC / PC / DMC 1:1:3 w/wRoom Temperature 0

20

40

60

80

100

120

140

160

0 1 2 3 4 5C-rate

Spe

cific

capa

city

(mA

h/g)

0.0

0.1

0.2

0.3

0.4

0.5

0.6

Dis

char

geen

ergy

(Wh/

g)

Before durability

After durability

200 cycles at 50oC


Electrode preparation, Cell preparation

Slurry Coating Calendar

Real electrode with good mechanical properties and performance

Cell

60 - 90 µm ~ 8-10 mg/cm2

150 mAh/g ~ 1.5 mAh/cm2

Standard electrolyte

Good adhesion Poor adhesion


0

50

100

150

0 100 200 300 400 500 600Cycle number

Spe

cific

capa

city

(mA

h.g-

1)

0

50

100

150

Effi

cien

cy(%

)

0

50

100

150

0 50 100 150 200 250 300Cycle number

Spe

cific

capa

city

(mA

h.g-

1)

0

50

100

150

Effi

cien

cy(%

)5 D

Performance & durability of DOW G2 materialDurability at Room T

Charging condition: CCCV 2.7 - 4.25V vs. LiDischarge: C rate calculated from 150mAh/gElectrode: C-LiFe0.2Mn0.8PO4, 2% Carbon, 5% PVDF

Total carbon in electrode 10%Electrode thickness: 41 micronLoading (AM): 5.4 mg/cm2

Electrolyte: LP30 + 1% VC

Durability at 50 C

Impressive performance and stability for DOW material

D/10

1D

0

20

40

60

80

100

120

140

160

180

0 1 2 3 4 5C-rate

Spe

cific

capa

city

(mA

h/g)

0.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

Dis

char

geen

ergy

(Wh/

g)

50 C

RT

Performance


DOW G2 material

0 2 4 6 8 10

50

100

150

200

Dis

charg

ecapacit

y(m

Ah/g)

Rates of discharge

C C C C C

LiNi0.5

Mn0.5

O2

LiNi0.33

Mn0.33

Co0.33

O2

LiNi0.4

Mn0.4

Co0.2

O2

LiNi0.8

Co0.15

Al0.05

O2

Dow performance: Bar-Ilan University

Dow rate performance exceeds alternatives


DOW stability at 50 oC : Bar-Ilan University

Bar-Ilan University confirm good stability

Dow’s“LiMnPO4 is the least surface reactive of all cathode materials studied;this is well expressed in very good cycleability.It’s rate capability is better than NCA and NMO”

Prof Aurbach, IMLB 2008, China

Cycle number


XANES measurements of DOW LiMnPO4

0

0,4

0,8

1,2

1,6

6540 6560 6580 6600 6620 6640

merge_021_d1_cartomerge_021_C0_2pos1merge_021_C0_2pos2merge_021_C0_4pos1merge_021_C0_4pos2merge_021_CO_6pos1merge_021_C0_6pos2merge_021_C0_8pos1merge_021_C0_8pos2merge_021_C1pos1merge_021_C1pos2

energy

MnPO4

LiMnPO4

0

0,4

0,8

1,2

1,6

6540 6560 6580 6600 6620 6640

merge_021_d1_cartomerge_021_C0_2pos1merge_021_C0_2pos2merge_021_C0_4pos1merge_021_C0_4pos2merge_021_CO_6pos1merge_021_C0_6pos2merge_021_C0_8pos1merge_021_C0_8pos2merge_021_C1pos1merge_021_C1pos2

energy

MnPO4

LiMnPO4

Displacement in lower energies:reduction of Mn (Mn3+ Mn2+)

DischargingCharging

0

0,4

0,8

1,2

1,6

6540 6560 6580 6600 6620 6640

merge_021_D0_2

merge_021_d0_4_carto

merge_021_D0_6

merge_021_D08

merge_021_d1_carto

merge_022PX3

energy

Li0.2MnPO4

LiMnPO4

Isobestic points

0

0,4

0,8

1,2

1,6

6540 6560 6580 6600 6620 6640

merge_021_D0_2


merge_021_D0_6

merge_021_D08

merge_021_d1_carto

merge_022PX3

energy

Li0.2MnPO4

LiMnPO4

0

0,4

0,8

1,2

1,6

6540 6560 6580 6600 6620 6640

merge_021_D0_2


merge_021_D0_6

merge_021_D08

merge_021_d1_carto

merge_022PX3

energy

Li0.2MnPO4

LiMnPO4

Isobestic points

Displacement in higher energies:oxidation of Mn (Mn2+ Mn3+)

• Both LiMnPO4 and MnPO4 phases are present during the charge and dischargeIsobestic points indicate a linear combination of each species

• No pre-peak change during charge/discharge – no perturbation on Mn octaedric site

• No Jahn-Teller effect (in contrast to MnO2 )

No structural re-arrangement : this explains the excellent durability

Tested at INM (Fr) PSI (Ch)


Dow performance 18650 prototype cell

Capacity at 1C: 900 mAhCycle: 4.25-2.0VCharge CCCV: CC 2 C/2

CV at 4.25 V until C/100

0 3 6 9 12 15 18 21 24

0

20

40

60

80

1000.5C

HPL- 18650 cell-5Gen 2.1 - LMPOV range: 4.25 ~2V

1C10C8C5C

2C

Ca

pa

city

rete

ntion

(%)

Cycle No.

1C


overcharge test 18650 cell with DOW cathode:

Voltage

Temperature

Voltage

Temperature

No smoke, no leakage and no explosionDow cathode is at the centre of a safe cell

Tested at Bar Ilan


Validation of safety: DSC parallel exp.

LiMnPO4 is safer than alternatives (similar to Iron Phosphate)

Tested at Bar Ilan


0

20

40

60

80

100

120

140

0 5 10 15Cycle number

Spe

cific

capa

city

(cat

hode

)[m

Ah/

g]

D/10 D/5 D/2 D 2D

1.7

1.9

2.1

2.3

2.5

2.7

2.9

0 10 20 30Time [hour]

Cel

lVol

tage

-6.00

-3.00

0.00

3.00

6.00

Cur

rent

[mA

]

Voltage

Current

100

125

150

0 50 100 150 200 250 300Cyclenumber

Spe

c.C

apac

ity(c

atho

de)

[mA

h/g] Cycle life at room T

D/2, C/5

Charge C/10– Discharge C/10Discharge capacity (C/5 charge)

Novel, safe, durable Li-ion : Li4Ti5O12-LiMnPO4

Li Titanate - Mn Phosphate: a safe, durable 2.5V power source


0.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

LiCoO2 LiFePO4 DowP

rice

of

Ind

ustr

ialL

i-Io

n($

/Wh

) Prodution

Other Materials

Cathode Materials

Price breakdown of a 3.6 Ah HEV Li-ion cell

Do not meet requirements:• LiCoO2 Not Safe, Cost• NMC,NCA Not Safe, Cost• LiMn2O4 Poor durability

Industry requirements:– Intrinsically safe– Low cost– Durable

Achieverequirements

LiFePO4

DOW

LiMnPO4

Voltage (vs. C) 3.2 3.85

Implication20% less

cells

Price ($/Wh)20% less

cost

In battery pack

20% more Voltage = 20% less cells in series

= 20% less electronics cost

Performance Li Mn PO4 achieves industry targets

Manganese Phosphate material can solve safety,battery cost, environment issues


Dow is an ideal partnerBreak-through technology

Unique Cathode material - LiMnPO4

Performance

Safe

Durability

Compatible with cell production

Industry cost target

Validated Protected technology

3 year advance in field

DOW technology & team

Numerous patents

Validated in demonstrator cells

Scale up in progress

Winning team

Quality supplier of fine chemical

World class products

Global logistics and support

Strong relations with Automotive

Technical leaders

Energy Storage Solutions

Dow’s history of innovation

Aim: preferred supplier of Li-ion material

Electrolyte high safety & performance

Binder nano-anodes & ecological

Separator high T stability

Dow enable Li-ion industrial applications

Documents

Advanced material selection for Li-ion solutions.pdf · © Dow 2010 All rights reserved June 2010 Advanced material selection for Li-ion Dow Chemical [email protected]