manufacturing r&d for low -cost, high-energy-density

ORNL is managed by UT-Battelle for the US Department of Energy

Manufacturing R&D for Low-Cost, High-Energy-Density Lithium-Ion Batteries for Transportation ApplicationsInternational Battery Seminar & ExhibitFort Lauderdale, FL3/23/17

David L. Wood, III, Zhijia Du, Marissa Wood, Jianlin LiOak Ridge National Laboratory

2 International Battery Seminar and Exhibition, March 23, 2017

Dramatic Cost Reduction Is Taking Place

• DOE and USABC have reduced LIB cost by 70% and doubled energy density since 2009.

• Source: D. Howell, “Overview of the DOE VTO Advanced Battery R&D Program,” 2016 DOE Annual Merit Review, Washington, DC, June 6, 2016.

• Updated Ultimate (2025) Targets: $125/kWh, 500 Wh/kg, 1000 deep-discharge cycles.


ORNL Is Addressing Three Major Problems:1. Advanced batteries are not being manufactured in the U.S.2. Advanced batteries have insufficient energy density.3. Advanced batteries still have high cost and insufficient long-term performance.

• Cost– Raw materials– Electrode processing– Cell manufacturing– Formation cycling– Module packaging

• Performance– Power limitations at low temperature– Low capacity at high discharge rates– Capacity fading

• Safety– Short circuiting– Overcharge– Over-discharge– Crush– Thermal runaway

• Life– Calendar life


Building a U.S. Supply Chain and Increasing Competitiveness of Domestic Industry

• ORNL provides a one-of-a-kind leadership facility for industry to collaborate

• Access and IP protected collaboration• Resource for

– Chemical and materials suppliers– Battery manufacturers and their customers– System integrators– Original equipment manufacturers

• Development of processes, process optimization, manufacturing schemes, materials improvements, diagnostics, and production yield


• R2R Manufacturing Team works with many external partners on raw material development.

• New binders, novel conductive additives, active material stability.

• Some internal work on active material synthesis.

LIB Manufacturing at the DOE Battery Manufacturing R&D Facility

at ORNL (BMF)

Raw materials

Slurry processing and mixing

Coating DryingElectrode processing

Cell assembly

Post processing Formation

© MediaTech

© SCS

© SCS


Pilot-Scale Processing of a Diverse Electrode Inventory

• 4 mixers• 6 R2R pieces

of equipment including 3 coating lines, corona treatment, and calendering

• 2 in-line UV lamps

Planetary Mixer (≤2 L)

Corona Plasma Treater (Surface Energy Modification)

Slot-Die Coating Line

Heated Calender (80,000 lbf)


ORNL Pouch Cell Assembly Equipment Enables Pilot-Scale Cell Sizes of Up to 7 Ah

Dry room for pouch cell assembly•Largest open-access battery R&D facility in US.•All assembly steps from pouch forming to electrolyte filling, wetting, and vacuum sealing.•1400 ft2 (two 700 ft2 compartments).•Humidity <0.2% (-53°C dew point or better maintained).•Pouch cell capacity: 80 mAh – 7 Ah.•Single- and double-sided coating capability.•Current maximum weekly production rate from powder to pouch cells is 50-100 cells.


Diverse and Industry Relevant BMF Research Portfolio1. R2R processing of battery, fuel cell, and supercapacitor electrodes2. Aqueous electrode processing3. Thick high-energy electrodes with novel architectures (≥200 micron calendered)4. High-Voltage Cathodes (HVCs) – LMR-NMC, Ni-rich NMC, coated NMC, etc.5. High-Capacity Anodes (HCAs) – Si, SiO, and SiSn alloy composites with C6. Post-mortem analysis of abuse-tested and cycled pouch cells7. Novel water-soluble binders8. Conductive carbon additive optimization (and substitution of C black)9. Effect of calendering on rate performance, capacity fade, and electrode structure10. Non-destructive evaluation of electrode coatings11. Formation-cycle time reduction and SEI layer characterization12. Capacity and voltage fade of Ni-rich NMC and LMR-NMC at high voltage13. Li-S coin cell testing and pouch cell design14. Electron beam and UV curing of electrode binders for solventless processing15. Solving specific industry problems (SPP, CRADA, and FOA projects)


Basics of Slot-Die Coating Process

Frontier Industrial Technology


Colloidal Science and Coating Considerations

Bergstrom, Adv. Colloid Interface Sci. 70 (1997) pp 125-169Bergstrom et. al., J. Am. Ceram. Soc. 79 [2] (1996) pp 339-348Hough & White, Adv. Colloid Interface Sci. 14 (1980) pp 3-41Prieve & Russel, J. Colloid Interface Sci. 125 [1] (1988) pp 1-13Benzing & Russel, J. Colloid Interface Sci. 83 [1] (1981) pp 178-190Hunter, Foundations of Colloid Science, 1&2 (1995)

Active material stability in water (ICP-MS) Surface charge stabilization (dispersants

and zeta potential) Solvent selection (surface tension

optimization) Mixing protocol (dispersants, order of

addition, etc. Rheological optimization (extent of

agglomeration, agglomerate size, viscosity, coating parameter optimization)

Drying protocol (electrode architecture, crack alleviation, particle cohesion, coating adhesion)


Approach to Combining Aqueous Processing with Thick, High-Energy Electrode Coatings

• Problems:– Excessive

agglomeration and settling in aqueous dispersions.

– Poor wetting and adhesion of water-based dispersions to current collector foils.

– Poor electrode flexibility, integrity, and power density of thick electrodes.

• Overall technical approach and strategy:

11

Cost analysis

Simulation of energy-power

density vs electrode thickness

Graded thick

electrodes

Electrode formulation

Dual slot-die

coating

Aqueous processing

Drying protocol

ModelingExperimental

Characterization/testing

Electrodearchitecture/

structure

Electrolyte wetting/diffusion

Pouch cell testing

Enables Si-based and Li metal anodes, and can be combined with solid-state electroytes!


All-Aqueous Cells Outperform Baseline NMP/PVDF Cells in Accelerated Life Test (2.0 mAh/cm2 Cathode Loading)

50

60

70

80

90

100

110

0.01 0.1 1 10

BaselineIndustry PartnerAll Aqu

Nor

mal

ized

Cap

acity

(%)

C-rate (C)

0

20

40

60

80

100

0 200 400 600 800

BaselineIndustriy partnerAll Aqu

Cycle No

Cap

acity

Ret

entio

n (%

)

1C/-2C

25oC

T increased to 30oC

NMC532: 12.6 mg/cm2; 50 µm; 36.8%CP-A12: 8.2 mg/cm2; 56 µm; 32.5%

NMP processed electrodesNMC cathode via aqueous processing (industry partner)Aqueous processed electrodes

- Cells have identical rate performance.- Baseline cells have the best capacity retention in the short-term. - Aqueous cells outperform baseline in the long-term.

1.5 Ah Pouch Cells


Excellent Cyclability in All-Aqueous Processed Pouch Cells (2.0 mAh/cm2 Areal Loading)

Excellent cyclability at 0.2C and 0.33C 84% capacity retention at 0.33C discharge rate after ~740 cycles Energy density at 169 Wh/kg at 0.2C

1000

1100

1200

1300

1400

1500

1600

1700

0

100

200

300

400

500

0.01 0.1 1 10C-rate (C)

Cap

acity

(mA

h)

Energy Density (W

h/kg) & Pow

er Density (W

/kg)

capacity

energy density

power density

25oC2.5-4.2V

50

60

70

80

90

100

0 100 200 300 400 500 600 700 800Cycle No

Cap

acity

Ret

entio

n (%

)

0.33C/-0.33C

30oC2.5-4.2V


Cracking of Thick (4-6 mAh/cm2 Loading) Electrodes is Problematic for Aqueous Processing

A. 15 mg/cm2 B.17.5 mg/cm2

C.20 mg/cm2 D.25 mg/cm2

• NMC/CB/binder=90/5/5• Aqueous processing• Slot-die coated• With the increase of loading

(thickness), cracks are developed and become profound.

Scale bar: 200 μm (A-D), 500 μm (E)

E.Calender 25 mg/cm2

Calendaring does not solve the problem.


Why Cracking Occurs: Cell Performance Can Be Improved at 4 mAh/cm2 Loadings If Cracking Is Alleviated

All particles are suspended in the solvent.

Air-solvent interface reaches the sediment surface. Menisci are formed between particles.

Capillary pressure builds up and local gaps widen.

Eventually, the film cracks to release stress.

ℎ𝑚𝑚𝑚𝑚𝑚𝑚 = 0.41 (𝐺𝐺𝐺𝐺𝜙𝜙𝑟𝑟𝑟𝑟𝑟𝑟𝑅𝑅3

2𝛾𝛾 )1/2

How thick can a coating be made without cracking?

The parameter that can be easily changed is 𝜸𝜸 – solvent surface tension.

R: particle radiusG: shear modulus of particlesM: coordination numberΦrcp: particle volume fraction at random close packing 𝜸𝜸: surface tension


Reducing the Surface Tension of the Solvent Reduces the Residual Stress Between Particles

• To lower the surface tension of water, another component is needed for this purpose.– Surfactants can be used for surface tension reduction, but usually lead to bubbling issues.– Common coating solvents can be used to form mixture with water for surface tension reduction.

Anal. Chem., 61, 194 (1989); J. Chem. Eng. Data 2010, 55, 2905–2908

VOC Exempt

As with water, the solvent recovery step is eliminated. Cost savings include reducing capital investment and energy input for recovery.

Solving Solvent Challenges • By Daniel B. Pourreau, Coatings Magazine, July-August, 2007


Coating Integrity and Morphology is Dramatically Improved with Small Amount of Methyl Acetate (MA)

Aqueous ProcessingCrack formation

90 wt% H2O + 10 wt% MANo cracking

NMP/PVDF BaselineNo cracking

25 mg/cm2

4.0 mAh/cm2


Full Pouch Cell (175 mAh) Rate Performance with 10% MA is Superior to Baseline NMP/PVDF Performance Cracked (pure water) cathode at 25 mg/cm2 has poor rate capability. Rate performance for the 25 mg/cm2 cathode processed with NMP or H2O/MA (9/1) is

slightly better than the 12.5 mg/cm2 electrode up to 2C. However, the H2O/MA (9/1) formulation does not cycle well compared to other formulations.

0.12 0.14 0.16 0.18(1/γ)1/2 (m/mN)1/2

12

16

20

24

28

32

36

Crit

ical

are

al lo

adin

g (m

g/cm

2 )

R² = 0.9346

0%

7%10%

12%

15%

20%

0 40 80 120 160 200cycle number

0.5

0.6

0.7

0.8

0.9

1

Nor

mal

ized

cap

acity

rete

ntio

n

H2O 12.5 mg/cm2

H2O 25 mg/cm2

NMP 25 mg/cm2

H2O/MA (9/1) 25 mg/cm2

H2O/IPA (9/1) 25 mg/cm2

H2O/IPA (8/2) 25 mg/cm2

% IPA in water

0.1 1Discharge C rate

0

20

40

60

80

100

Perc

enta

ge o

f ful

l cap

acity

H2O 12.5 mg/cm2

H2O 25 mg/cm2

NMP 25 mg/cm2

H2O/MA (9/1) 25mg/cm2

H2O/IPA (9/1) 25 mg/cm2

H2O/IPA (8/2) 25 mg/cm2

0.33C/-0.33C


Energy Density Plateaus With Increasing Electrode Thickness

• graphite: 10μm• Baseline: NCA 2μm; 1.0M LiPF6• a: NCA NCA 500 nm; 1.0M LiPF6• b:NCA 2μm; 1.5M LiPF6• c: NCA 500 nm; 1.5M LiPF6

Z. Du, D.L. Wood, III, C. Daniel, S. Kalnaus, and J. Li, “Understanding Limiting Factors in Thick Electrodes for High-Energy-Density Li-Ion Batteries,” Journal of Applied Electrochemistry, Accepted, 2017.

60 90 120 150 180 210 240Cathode thickness (μm)

500

550

600

650

700

750

Ener

gy d

ensi

ty (W

h/L)

Baseline(a)(b)(c)

Black C/5,Blue C/2, Cyan 1C,Red 2C

CathodeNCA, 70 vol%

Al foil, 15 um

Cu foil, 15 um

Separator, 20 um

Separator, 20 um

AnodeGraphite 70 vol%

AnodeGraphite 70 vol%

CathodeNCA, 70 vol%0

• Modeling with NCA cathode shows that increasing electrode thickness results in mass-transport limitations (high concentration polarization).

• Three ways to alleviate this problem are to: 1) raise the electrolyte salt concentration; 2) reduce active particle size; or 3) introduce graded electrode architectures.


Dual-Slot-Die Coating Leads to Better Graded Pore Structures and Particle Size Gradients

Dual Slot Die Coating Lips

Slurry for Bottom Coating Slurry for

Top Coating

Slot Die


Several Basic Cathode and Anode Coating Configurations Are Being Investigated at 4-6 mAh/cm2)

Mixed Particle Sizes (6 µm & 12 µm, 50/50 wt%)

12 µm Particles on Bottom / 6 µm Particles on Top

6 µm Particles on Bottom / 12 µm Particles on Top

All Small Particles (Control; 6 µm)

Al

Al Al

Al

1 2

3 5 4 6(2-Pass) (Dual Slot Die) (2-Pass) (Dual Slot Die)


Bilayer Structure Well Preserved after CalenderingAs Coated Calendered to 30% Porosity

5

6

Al

Al

Large particles on bottom / Small particles on top (Dual Slot-Die)

Small particles on bottom / Large particles

on top (Dual Slot-Die)


Differences in Particle-Size and Pore-Size Gradients (NMP)

0

10

20

30

40

50

60

70

80

90

100

0.1 1 10

% o

f Ini

tial C

apac

ity

C Rate

Rate Performance ComparisonAMO Coating #3 Avg: 2-Pass LargePart Bottom/Small Part Top

AMO Coating #4 Avg: 2-Pass SmallPart Bottom/Large Part Top

AMO Coating #5 Avg: Dual Slot DieLarge Part Bottom/Small Part Top

AMO Coating #6 Avg: Dual Sot DieSmall Part Bottom/Large Part Top

Coatings with the large 12 µm particles on the bottom and small 6 µm particles on the top show slightly better rate performance at high C rates than coatings with the opposite configuration

25 mg/cm2

4.0 mAh/cm2


Anode Performance Suffers At High Areal Loadings (NMP)

5

10

15

20

25

30

35

40

0 200 400 600

Spec

ific

Cap

acity

(mA

h/g)

Cycle No

High-Rate Cycle Life Comparison: ~6 mAh/cm2

Showa Denko

Hitachi MAGE 3

Superior SLC 1520T

1C Charge, 2C DischargeHPPC every 50 Cycles

70

90

110

130

150

0 100 200 300 400

Spec

ific

Cap

acity

(mA

h/g)

Cycle No

High-Rate Cycle Life Comparison: ~2.6 mAh/cm2

Showa Denko

Hitachi MAGE 3

Superior SLC 1520T

1C Charge, 2C DischargeHPPC every 50 Cycles


Conclusions and Future Work• State-of-the-art pouch cell performance can be achieved with aqueous NMC 532 and

graphite processing at conventional areal loadings of 2.0-2.5 mAh/cm2 (~50 µm and 12-16 mg/cm2 NMC 532). How do we solve the fast initial capacity fading observed at high discharge rates? Formation modification, particles coatings, electrolyte additives, etc.

• Aqueous LIB electrode processing can be enhanced with VOC-exempt solvents such as methyl acetate (MA), while improving rate performance.

• Dual slot-die coating is an effective method for making electrode architectures with particle-size and pore-size gradients, as well as multi-layer (>2 layers) coatings.

• Graded electrode architectures must be implemented at both anode and cathode to maintain good high-power (C-rate) performance.

• MA approach will be combined with dual slot-die approach to make full pouch cells with graded cathodes and anodes (and study associated capacity fade).

• Aqueous processing formulation chemistry, mixing protocol, and coating parameters are being developed for Ni-rich cathodes (i.e. NMC 811 and NCA).


DOE and R2R Manufacturing Team AcknowledgementsStaff:

Jianlin LiZhijia Du

Rose RutherClaus DanielDavid Wood

Post-Docs:Lamuel DavidKevin Hays

Chengyu MaoYangping ShengMarissa Wood

PhD Students:Seong Jin AnNate Phillip

Technicians:Jesse AndrewsTJ Christensen

Vehicle Technologies Office Sponsors:

Peter FaguyDavid Howell

Advanced Manufacturing Office

Sponsors:David Hardy

Mark Johnson

Vehicle Technologies OfficeAdvanced Manufacturing Office

manufacturing r&d for low -cost, high-energy-density

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