Advanced Energy Storage and the Importance of Graphite ...€¦ · •540,000 EVs sold in US in 2016, < 50 incidents + 1 fire in >10,000 vehicles •Gasoline fires are explosive,

© 2017 PUREgraphite, LLCAll Rights Reserved

July 19, 2017 1

Advanced Energy Storage and the Importance of Graphite

Anode MaterialsDr. John C. Burns – CEO Novonix, Canada

Dr. Edward R. Buiel – CEO PUREgraphite, USA


July 19, 2017 2

• LIB Raw Materials+ How much of what is in each cell?

• Battery Safety

• Natural Graphite Quality for LIBs+ Is larger flake or small flake battery?

+ Purity of the resource and contamination?

+ Is one deposit better than another?

• LIB Life Predictions+ Is Graphite important or just along for the ride?

Overview


July 19, 2017 3

LIB Raw Materials


July 19, 2017 44

Raw Materials in LIBs

• 40-60% cost is raw materials

• Cathode = 16%

• Anode = 6%

• Data from Christophe Pillot (AvicenneEnergy - 2016)


July 19, 2017 55

Cathode Materials in LIBs

• Li[Ni0.6Mn0.2Co0.2]O2 is taking LCO market share in portable electronics and is primarily used in EVs

+ Elemental metals mass breakdown:➢ Li: 11%➢ Ni: 54%➢ Mn: 17%➢ Co: 18%

• Li[Ni0.8Co0.15Al0.05]O2 is used by Panasonic in Tesla cells+ Elemental metals mass breakdown:

➢ Li: 11%➢ Ni: 78%➢ Co: 9%➢ Al: 2%

• Data from Christophe Pillot (Avicenne Energy - 2016)


July 19, 2017 66

Anode Materials in LIBs

• Natural graphite and artificial graphite are primary materials

• Natural is typically cheaper and used in lower end applications.

• Market for artificial graphite likely to grow with EV demand.

• Data from Christophe Pillot (Avicenne Energy -2016)


July 19, 2017 77

Total Material Breakdown

• Estimates for NCA/Gr 18650 cell:+ Cell weight: 50g

+ Cathode active weight: 20g➢ Lithium: 1.4g

➢ Nickel: 10.4g

➢ Cobalt: 1.2g

➢ Aluminum: 0.2g

+ Anode active weight: 10g➢ Graphite: 10g

+ Electrolyte: 5g➢ Lithium: 0.35g

+ Inactive material (foils, separator, housing): 15g

“Our cells should be called Nickel-Graphite, because primarily the cathode is nickel and the anode side is graphite with silicon oxide… [there’s] a bit of lithium in there but its like the salt on the salad”– Elon Musk (June 2016)


July 19, 2017 88

Battery Requirements

• Different applications have very different demands for lifetime and power.

• Cells are designed with different materials to meet these demands at different price points.

Material Demand Lifetime Requirements Cost


July 19, 2017 99

Battery Safety

• Primary concern of major cell suppliers to consumer industries

• When built well, lithium-ion cells can be very safe

• When built “cheap”, lithium-ion cells can be very dangerous

Hoverboards and e-cigarettes have a low quality cells in them and have experienced a high

degree of failures

~100,000 Tesla vehicles on the road~8,000 cells per vehicle

~800,000,000 cells< 50 battery safety incidents

~50 part per billion


July 19, 2017 1010

Battery vs Gasoline Safety• 2003-2007 – 287,000 vehicle fires per year and in 2015 264M gas cars were on the road:

+ 1 fire in ~1,000 vehicles

• 540,000 EVs sold in US in 2016, < 50 incidents+ 1 fire in >10,000 vehicles

• Gasoline fires are explosive, lithium ion fires are harder to start and they do not propagate quickly with properly built battery packs.

Gasoline car fire


July 19, 2017 11

Graphite Processing


July 19, 2017 12

Conventional Natural Graphite Process

• Chinese yield is only 30%

• Yield cost up to $1,000/ton

• Difficult to use HCl/HF in the US

• Needs improvement in consistency

• Significant residual impurities

• Requires calcination

• Not environmentally friendly

Spheronizing

HCl/HF Purification

Pitch Coating

Calcination


July 19, 2017 13

Natural Graphite Quality for LIBs


July 19, 2017 14

Natural Graphite Resources

• Large reserves of graphite with companies actively working to develop the resource

• Coulometrics has worked with about a dozen sources all over the world to sample and test the flake


July 19, 2017 15

Rigorous Flake Concentrate Analysis

• FLAKE ANALYSIS TESTING:

• Sieve samples to sizes shown in Table below.+ +50, 50x100, 100x200, 200x400, 400x635, -635 mesh + Measure masses to get flake size distribution (Table 1)+ Tap Density and LOI (Table 2)+ Measure BET (Table 3)

• Grind samples to -635 mesh+ Repeat BET+ XRD + EChem

➢ Build and test coin cells


July 19, 2017 16

G16-0114Natural Graphite SampleSieve Analysis

Coulometrics Control #

Flake Size(mesh)

Particle Size(mm)

Mass in Sieve(g)

Size Fraction(%)

G16-0114

+50 0.300 0 0%

50x100 0.300-0.150 0 0%

100x200 0.150-0.075 7.66 3.4%

200x400 0.074-0.037 56.76 25.4%

400x635 0.037-0.020 98.98 44.2%

-635 0.020 60.41 27.0%


July 19, 2017 17

G16-0114Natural Graphite SampleTap & Ash Analysis

ID#Flake Size

(mesh)Tap Density

(g/cc)

LOI – Ash Content (% carbon)

Sample 1 Sample 2 Sample 3 Average

G16-0114

As Received 0.53 96.37 96.43 96.49 96.43

+50 No material after sieving

50x100 No material after sieving

100x200 0.48 97.79 97.81 N/A 97.80

200x400 0.45 97.71 97.34 97.53 97.53

400x635 0.41 96.95 96.91 97.00 96.95

-635 0.40 94.26 93.24 94.48 93.99

Fine material concentrates impurities


July 19, 2017 18

G16-0114GSP Ore, Graphite ConcentrateBET Analysis

ID#Flake Size

(mesh)

BET SA (As Received) BET SA (Ground to -635)

Ads.(m2/g)

Des.(m2/g)

Avg.(m2/g)

Ads.(m2/g)

Des.(m2/g)

Avg.(m2/g)

G16-0114

As Received 5.40 5.32 5.36 5.71 6.37 6.04

+50 Not enough material after sieving

50x100 Not enough material after sieving

100x200 3.39 3.41 3.40 6.67 6.43 6.55

200x400 4.11 4.18 4.15 5.94 6.08 6.01

400x635 5.08 5.07 5.08 7.04 6.86 6.95

-635 6.29 6.36 6.33 N/A N/A N/A


July 19, 2017 19

PURITY?


July 19, 2017 20

G16-0114GSP Ore, Graphite ConcentratePIXE Analysis

• Significant Impurities including:+ Al, S, Fe, and Si: 2400 - 4330ppm

➢ S (4560ppm)

➢ Si (7690ppm)

➢ Fe (2400 ppm)

➢ Al (3840ppm)

+ Smaller amounts of Na, Mg, Cl, K, Ca, Ti, Cr, Mn, Ni, Cu, Zn, Ga, As, Br, Rb, Zr, Mo….

Carbon ID Description Na Mg Al Si P S Cl K Ca Sc Ti V Cr Mn Fe Co Ni Cu

G16-0114 Graphite Corp 367 327 3840 7690 4560 62 976 167 156 37 6 2400 21 107

Zn Ga Ge As Se Br Rb Sr Y Zr Nb Mo Tc Rh Pd Ag Cd In Sn Sb Te I Cs Ba La Ce Pr Nd Pm Sm Eu Gd Tb

10 1 3 5 10 8 36

Dy Ho Er Tm Yb Lu Hf Ta W Re Os Ir Pt Au Hg Tl Pb Bi Th UTotal -ppm

20789

ID#


Sample 1

Sample 2

Sample 3

Average

G16-0114 96.70 96.78 96.74 96.74


July 19, 2017 21

G16-0159Graphitized/Purified GSP OrePIXE Analysis

• Significant Impurities including:+ Al, Si, and Mo : 15 - 50ppm

+ Fe <10ppm

Carbon ID Description Na Mg Al Si P S Cl K Ca Sc Ti V Cr Mn Fe Co Ni Cu

G16-0159 Graphite Corp PF 50 22 8 5 1.8

Zn Ga Ge As Se Br Rb Sr Y Zr Nb Mo Tc Rh Pd Ag Cd In Sn Sb Te I Cs Ba La Ce Pr Nd Pm Sm Eu Gd Tb

15

Dy Ho Er Tm Yb Lu Hf Ta W Re Os Ir Pt Au Hg Tl Pb Bi Th UTotal -ppm

101.8

ID#


Sample 1

Sample 2

Sample 3

Average

G16-0159 99.99 100.00 99.99 99.99

Natural Graphite will NEVER EVER EVER not need to be purified….


July 19, 2017 22

Electrochemistry?


July 19, 2017 23

G16-0114: As ReceivedElectrode Preparation

• Electrode Mixing Information:+ Active material (G16-0114): 2.54g

+ Conductive carbon (SFG-6L): 0.056g

+ Binder (Kynar HSV900/NMP): 6.0%

• Electrode Properties+ Active mass: 92.0%

+ Loading: 13.76 mg/cm2

+ Calendered Density: 1.700 g/cc


July 19, 2017 24

G16-0114: As Received1M LiPF6 in EC/DEC (1:1) Additives: NoneElectrochemical Data

• C/20 cycling+ Rev. Cap

➢ 364 - 368 mAh/g

+ Irrev. Cap.➢ 47.9 - 49.9 mAh/g

+ First cycle efficiency➢ 87.1 - 88.1%


July 19, 2017 25

G16-0114: 100x200 Mesh1M LiPF6 in EC/DEC (1:1) Additives: NoneElectrochemical Data


➢ 364 - 366 mAh/g

+ Irrev. Cap.➢ 42.4 - 46.2 mAh/g



July 19, 2017 26



➢ 374 - 375 mAh/g

+ Irrev. Cap.➢ 48.3 - 50.1 mAh/g

+ First cycle efficiency➢ 88.0%


July 19, 2017 27



➢ 371 - 372 mAh/g

+ Irrev. Cap.➢ 49.9 - 51.4 mAh/g



July 19, 2017 28

G16-0114: -635 Mesh1M LiPF6 in EC/DEC (1:1) Additives: NoneElectrochemical Data


➢ 351 mAh/g

+ Irrev. Cap.➢ 59.6 mAh/g



July 19, 2017 29

G16-0114GSP Ore, Graphite ConcentrateElectrochemical Data Summary

ID#

Flake Size

Ground to -635 mesh

eChem Results

Rev. Capacity(mAh/g)

Irrev. Capacity(mAh/g)

First Cycle Efficiency(%)

G16-0114

As Received 367 47.9 88.1

+50 Not enough material after sieving

50x100 Not enough material after sieving

100x200 366 42.4 88.6

200x400 375 48.3 88.0

400x635 371 49.9 88.1

-635 351 58.6 85.4

Lower Rev.Cap. due to impurities


July 19, 2017 30

Natural Graphite Resources

• Samples from all over the world show the same capacity and similar process ability

• Samples are largely interchangeable if fines (-635 mesh) is removed


July 19, 2017 31

LIB Lifetime


July 19, 2017 32

Standard Cell Cycling at 21°C

• Cells cycle with limited capacity loss

• Variation in cell capacity are more a reflection of temperature stabilitythan cell capacity loss


July 19, 2017 33

Cell Cycling

• Why do cells fail this way?+ See Jeff Dahn Win Talk and

explanation above

• What can you do?+ High Precision Coulometry

➢ Measure loss of electrons per cycle due to oxidation/reduction of the electrolyte

Cap

acit

y

Cycle Number

Cycles flat

Dies Quickly

Use HPC (High Precision

Coulometry) to determine

this point.


July 19, 2017 34

HPC? Google Jeff Dahn Win Talk

© 2017 Coulometrics, LLC.

All rights reserved.34


July 19, 2017 35

Prof. Jeff Dahn – WIN Talk

• Fresh cell

• Battery is charged and electrolyte starts to become oxidized on the positive electrode


July 19, 2017 36


• Newish cell

• Reduction products start continue SEI layer growth on anode


July 19, 2017 37


• Half way through life

• SEI layer thickening

• Pores start to close


July 19, 2017 38


• Near end of life

• SEI has grown to the point where pores are beginning to clog and it is difficult for lithium to penetrate into the graphite anode material


July 19, 2017 39


• End of life

• SEI has blocked access of lithium into the pores

• Lithium plating occurring on surface of the anode

• Lithium inventory is reduced each cycle and cell fails quickly


July 19, 2017 40

Cell Cycling

• Why do cells fail this way?+ See Jeff Dahn Win Talk and

explanation above

• What can you do?+ High Precision Coulometry

➢ Measure loss of electrons per cycle due to oxidation/reduction of the electrolyte

Cap

acit

y

Cycle Number

Cycles flat

Dies Quickly

Use HPC (High Precision

Coulometry) to determine

this point.


July 19, 2017 414141

Coulombic Efficiency & Cell Life:Rapid Capacity Loss Cells

0 100 200 300 400

Moli Cycles

1.6

1.8

2

2.2

Ca

pa

cit

y (

Ah

)

0.992

0.996

1

CE

2100

2200

2300

2400

Ch

. E

nd

.C

ap

. (m

Ah

)

0 4 8 12 16 20

HPC Cycles

Control

VC

FEC

VC + FEC

11.91 mAh/cycle3.956 mAh/cycle5.333 mAh/cycle2.754 mAh/cycle

J. Electrochem. Soc., 160, A1451-A1456 (2013).

• Highest CE = longest life until rapid capacity loss

• Lowest CE = shorted life until rapid capacity loss


July 19, 2017 43

HPC Testing

• HPC Testing results

• Tesla Cells+ 2013 Model S

+ Removed from damaged vehicle

+ 2.5-3.0 CIE/h

• STD Natural Graphite+ 5.0-6.0 CIE/h

C/20 to C/30 Cycling at 40°C

PUREGraphite

Gen2 – Graphite

Graphite is really important for

life!


July 19, 2017 44

This work was supported by:National Science Foundation under Grant No. 1315040 (CVD

Process for Coating Graphite)

and by:Department of Energy under Grant No. DE-SC0015953 (High yield

spheronization).

Contact information:

Dr. Edward R. Buiel

Coulometrics, LLC

423-954-7766

[email protected]

Thank You!

Documents

Advanced Energy Storage and the Importance of Graphite ...€¦ · •540,000 EVs sold in US in 2016, < 50 incidents + 1 fire in >10,000 vehicles •Gasoline fires are explosive,