Developing Markets for Natural Graphite

By George C Hawley, President

George C. Hawley & Associates Supermin Enterprises

Geophil33@gmail.com

877-335-8923

Prepared for: IM Graphite Conference – Graphite

December 6-7 19, 2011, London, UK

Biographical

• George C Hawley is an international consultant, specializing in the development

and marketing of value-added products based on industrial minerals. • His work in the industrial mineral sector goes back to 1970. • His education and experience are in chemistry, chemical engineering and

polymers. He is a member of the US Society of Plastics Engineers • His background in graphite goes back to the 1950’s when he was Research,

Development and Quality Assurance Chemist for Morgan Crucible Company, the world’s second largest synthetic graphite product maker.

• Specific projects were nuclear, rocket nozzles, chemical, anodes, brushes, and

friction materials.

• He has been working on the development of Canadian graphite since 2000. • In the 1950’s, he also worked on R & D and Process Control of lead acid batteries

for a division of Chloride/Exide group. • Specific projects were electrodes, separators and casings.

Abstract

Natural graphite is undergoing a resurgence.

Graphite has a unique range of properties including refractoriness, high dimensional stability, chemical inertness,

high electrical and thermal conductivity

The existing end uses remain strong.

New uses are developing especially in energy –related markets.

Paramount in these is the use in lithium ion battery anodes.

Nature of Graphite

• Graphite - native carbon 3 covalent bonds at 120 degrees in a plane. (graphene)

•

• 4th bond forms electron gas below and above plane, spacing 0.34 nm.

Electron gas is mobile = high electrical & thermal conductivity in plane

• But much less perpendicular to plane.

•

• Similar anisotropy in thermal expansion and diamagnetism

•

• Natural form is flake. Layers slide on each other on film of air or water

•

• 2 crystal arrangements – slightly different properties

•

• Hexagonal graphite ( alpha) ABAB Rhombohedral ( beta) ABCABC

• Alpha converts to Beta on pulverising Beta converts to Alpha above 1000 deg C

•

• Alpha graphite is semi-metallic Beta graphite is a semi-conductor.

•

• Natural flakes 70% alpha + 30% beta. Synthetic graphite is pure alpha graphite.

• Key Properties of Natural Graphite • Low electrical resistivity (especially in the plane) Low thermal expansion (negative in the plane)

•

• High specific heat High Thermal conductivity (especially in the plane)

•

• High melting point (3550 degrees Celsius) Excellent thermal shock resistance

•

• High refractoriness Low chemical reactivity (slowly oxidised)

•

• Low Porosity Hydrophobic & not wetted by molten metals & slags

•

• High Lubricity Low Hardness (less machine wear) High strength & stiffness

•

• Low Density (SG 2.2) ( compared to metals & non-metals) High diamagnetism

•

• Low neutrons & X-rays absorption High absorption of microwaves IR reflective

• Intercalatable – expandable graphite and lithium ion batteries

Graphene Definition: Graphene is a one-atom-thick planar sheet of sp2-bonded carbon

atoms that are densely packed in a honeycomb crystal lattice Thickness

Graphene 0.335 nm human hair 100,000 nm Strength

Breaking stress 130 GPa ( steel 0.4 GPa, at 7.8 g./cc)

Stress to break 10 cm ribbon 1lb

Resistivity, ohm/cm Graphene 1 x 10-6 silver 1.59 x 10-6 copper 1.68 x 10-6 silicon 6.4

Electron mobility,cm2/V.s

Graphene 15,000 silicon 1,400

Absorption of white light 2.3%

Requirement to replace 4 - 8 nm ITO in touch screens 6 - 12 tonnes

Price – 100 g 12 nm thick “ graphene” $495

Copyright 2010- George C Hawley & Associates

Developing markets The high price of oil and its products, shortages and

environmental concerns with fossil fuels, will have a great effect

on minerals demand.

These changes are in the sectors of:

Energy Sources

Energy Storage

Energy Control

Energy Sources

• Nuclear

• Solar

• Wind/wave /tidal

Non -Nuclear Energy Sources Solar Energy

Potential for graphene transparent electrically conductive layer

Wind/Wave/Tidal

Potential for composites based on partial substitution of graphene/ expanded graphite for

carbon fibers in high strength/high stiffness composites.

Energy Storage Applications Batteries

Lithium Ion Lithium Ion polymer Lithium bromide

Fuel Cell

Flow Battery Bipolar Plates

Supercapacitors

Energy Control Applications Building Envelope

Phase Change Material encapsulation (expanded) Polystyrene foam insulation (micronised)

Wall & ceiling heating elements (expanded/graphene)

Fire protection (expandable)

Fire stopping/barriers Polyurethane foam upholstery

Conductivity Heat sinks – computer chips(expanded) electrostatic painting (micronised & expanded)

Oil & Solvent Spill Management ( Expanded)

Resistive De-icing ( expanded/graphene)

Parking garages Aircraft Power lines

Composites ( expanded/graphene) Aircraft Wind Turbine Automotive Sporting Goods

Copyright 2010- George C Hawley & Associates

Nuclear Energy - Pebble Reactors

Graphite content in the graphite matrix of Triso pebbles is

25 - 65% natural, balance synthetic.

Calculated natural graphite needed for 110 MWe pebble

reactor

For commissioning 100 tonnes;

Annual pebble replacement 19 – 35 tonnes

Copyright 2010- George C Hawley & Associates

PBMR vessel, turbines, and generator

Copyright 2010- George C Hawley & Associates

Nuclear Plants – Existing & Future

Status

Jan 2007

China

plants

China

MWe

Russia

plants

Russia

MWe

Japan

plants

Japan

Mwe

India

Plants

India

Mwe

World

plants

World

Mwe

Operating 11 8,587 31 21.743 55 47,577 17 3,779 439 372,059

Building 5 4,540 7 4,920 2 2,285 6 2,976 34 27,798

Planned 30 32,000 8 9,600 11 14,945 10 8,560 93 100,595

Proposed 86 68,000 20 18,200 1 1,100 9 4,800 222 193,095

Total 121 104,540 35 32,720 14 18,330 25 16,336 349 321,488

2011

China – 14 operating,

26 in construction – 2 PBMR.

Sources: Reactor data: WNA to 14/01/08.IAEA- for nuclear electricity production & percentage of electricity (% e)

Lithium Ion Batteries (LIB)

• Rechargeable (secondary) lithium ion batteries are rapidly replacing other types because of their high voltage, high capacity, longevity, and light weight.

• 67% of all portable secondary batteries in Japan are LIB.

• They are now used in cell phones, laptops and power tools.

• They are a common, but expensive, alternative to lead acid batteries used in electric bikes and are starting to be used in electric cars and trucks.

• Because of high petroleum prices and global warming due to carbon emissions from internal combustion engines, the future of LIB is bright.

• In view of the projected growth, availability of components is key.

Lithium Batteries 101

• Lithium ion batteries consist of two electrodes - a cathode of some

lithium- containing compound, and an anode which is most commonly graphite based.

• Both active materials are mixed with polymer and coated onto metallic

foil which carries the electrons to the exterior. • These electrodes are insulated from each other by a permeable

polymeric separator. • The ions move through an organic electrolyte. This is reactive with the

anode graphite, causing loss in capacity (irreversible capacity), but has some benefits. A graphite anode must be coated to optimize this.

• Lithium metal is the ideal anode, but it is highly reactive with water and

air, and can catch fire. The problem is overcome by using an anode of a substance that can intercalate lithium ions, which react reversibly with it.

Desirable Characteristics of LIB Anode Materials

• High reversible capacity • Low Irreversible capacity (due to reaction with electrolyte) • Good electrical and thermal conductivity • Dimensional stability • Long life • Easy processing • Non-reactive with other components – safety • LOW COST (especially for automotive applications)

Availability of Components

• Lithium is plentiful.

• Graphite is the least expensive of intercalating substances. There are many others. But all have disadvantages – low voltage, high expansion, poor life, poor conductivity, and high cost.

• Synthetic graphite is satisfactory, and has a large source in petroleum coke. But natural graphite has lower cost and higher capacity.

• The weight of graphite required is theoretically 10.4 times that of lithium, but is closer to 13 X due to inefficiencies. It works out to be about 2 x LCE.

• China produces 73% of the world’s natural graphite, Canada only 2.3%.

• China has applied export licences, export duties and VAT on graphite exports increasing the cost at mine site by 50%. This and scarcity has increased graphite prices by a factor 3.5 over historic levels.

• China has announced intention to be the world leader in electric vehicles.

• The largest use of graphite is in refractories for the steel industry. So growth of LIB will compete with the steel industry which has been growing in China at the rate of 8- 12 % annually.

Negative electrodes

Electrode

material

Av.potential

difference, volt

Specific capacity,

mA.h/g

Specific energy,

kW.h/kg

Graphite, LiC6 0.1- 0.2 372 0.0372- 0.0744

Titanate,

Li4Ti5O12 1- 2 160 0.16- 0.32

Silicon,

Li4.4Si 0.5- 1.0 4212 2.106- 4.212

Germanium

Li4.4Ge 0.7- 1.2 1624 1.137- 1.949

New Possibilities for Graphite Anodes

Capacity, mAh/g

LIC6 372

Li C2.33 900

LiC1.0 2238

New Possibilities for Graphite Anodes (2)

Li+ only intercalates via edges of graphite

Time to charge depends on the velocity of the lithium ions

Solution:

perforate the graphite to allow entrance of the ions

Result:

charging time reduces 10 x

New Possibilities for Lithium Ion Batteries

Lithium bromide cells

Lithium and bromine both intercalate in graphite

Bromine can be displaced by heat at 80 0C +

LiBr battery can be recharged by waste heat

Cost of Lithium Ion Batteries for Vehicles ANL May 2000

High Energy Cell Material Price/kg g/cell % Cell cost

Cathode 55 1,408 48.8

Electrolyte 60 618 23.4

Graphite 30 563.6 10.7

Separator 180 60.5 6.9

High Power Cell Material Price/kg g/cell % Cell cost

Cathode 55 64.8 28.2

Electrolyte 60 44 20.9

Graphite 30 12.7 3.0

Separator 180 16.4 23.3

Selected Properties of Lithium Ion

Battery Anode Materials

Material Density

g/cc.

Thermal

Conductivity

W/m.K

Resistivity,

Ohm.m

Graphite 2.26 470

25

10-7-10-6 in basal plane

10-5-10-2 perpendicular

Silicon 2.40 149 6.4 x 10-2

Germanium 5.36 58 4.6 x 10-1

Lithium 0.53 84.8 9.28 x 10-3

Note: Lower electrical resistivity means greater conductivity

Expansion of Lithium Ion Battery Anode Materials on Charging and Discharging

Graphite +/- 10% Silicon +/- 300% Germanium +/- 370%

Compare with

Ice /Water Freeze Thaw +/- 9.97%

Comparison of Typical Carbon

Capacities (Enerdel) Material Initial

capacity,

mAh.g

Reversible

capacity,

mAh.g

Irreversible

capacity,

mAh.g

% First

Cycle

Efficiency

Graphite 390 360 30 92

Hard

Carbon

480 370 90 77

Soft

Carbon

275 235 40 85

Note:

Non –graphitizable hard carbon is made from precursors that

char as they are pyrolized.

Chinese Graphite for Lithium Ion

Batteries Particle

size,

D50

microns

Fixed

Carbon, %

Tap

Density,

g/cc

Surface

Area

m 2 /g.

Discharge

Capacity

mAh/g

Natural 12 – 25 >= 99.95 >= 1.0 3.5 – 7.5 360-370

MCMB 8 - 16 99.9 -99.96 1.30 – 1.42 1.0 – 2.5 320-340

Notes:

1. Natural graphite manufacturers micronize, process into potato shape and purify their

concentrates.

Battery manufacturers add proprietary coatings to reduce electrolyte reaction.

Spacing between planes – 0.335 nanometers.

2. MCMB = MesoCarbonMicroBeads, Made by controlled carbonisation of pitch from which low

molecular weight fractions have been volatilised.

Then the residues are extracted by solvent. The product is then graphitised.

Known as “Soft Carbon”

Spacing between planes – 0.375 nanometers.

Notes:

1. All products except A12 are based on petroleum coke.

2. CPreme coat the coke particles to make them rounder.

3. ConocoPhillips produces annually 5 million out of 80 million tons coke world total.

4. A12 is based on natural graphite. Its capacity is higher than the coke-based anode

graphite.

Positive electrodes

Electrode

material

Av. potential

difference, volt

Specific capacity,

mA.h/g

Specific energy,

kW.h/kg

LiCoO2 3.7 140 0.518

LiMn2O4 4.0 100 0.400

LiFePO4 3.3 180 0.495

Li3V2 (PO4) 3 3.0 – 4.2 131.2 n.a.

Price of Lithium Ion Battery Anode Materials

US$/kg World Production tonnes Natural Graphite, 99.95% 10 - 30 2000 – 3000 total natural graphite 1.1-1.6 million (potential demand for LIB 0.5 – 1.0 million) Synthetic Graphite, 99.99% 15 - 60 84,500

Silicon, 99.99% 65 31,800 (total silicon) (780,000) Germanium, 940-1425 120

World Vehicle Production, 2010

Region Million units

World 77.86

China 18.26

USA + Canada + Mexico 12.17

Japan 9.61

Germany 5.91

S. Korea 4.27

India 3.54

UK 1. 39

Forecast 2015 ( PricewaterhouseCoopers ) 97

Estimation of Graphite Demand for Vehicular Lithium Ion Battery Anodes

Cumulative Lithium Demand from 2010 to 2100 for Electric Vehicles

Kg Lithium per vehicle

Hybrid EV Plug In Hybrid EV Battery EV

0.068-0.091 1.48-2.28 5.13-7.70

Gruber et al., Global Lithium Availability and Electric Vehicles, Journal of Industrial Ecology, July 2011

Calculated Equivalent Demand for anode graphite *

tonnes per million vehicles

710 – 950 15,390 -23,710 53,350-80,080 * Assumes 100% efficiency.

Electric Local Delivery Vehicles

Fedex 43 EV

Purolator 955 HEV

UPS 128 EV ( out of 2,200 alternative energy vehicles including HEV, biodiesel,

LNG, CNG and propane

USPS (proposed) 20,000 EV LA Airport eBus -12 EV

Lifetime fuel savings $0.5 million

School buses city buses submarines

Conclusions 1. Natural graphite is finding new markets mainly related to energy .

2. It is the best choice now available as a precursor for lithium ion battery anodes for EV.

3. It is abundant in nature and has the lowest cost.

4. It has high electrical and thermal conductivity.

5. Its characteristics and performance are well known.

6. For LIB anodes, it must be micronized, spheronized, purified and coated

7. Synthetic graphite makes an excellent anode. It is already fairly pure and rounded.

8. It is abundant as a by-product of refining of certain petroleum products.

9. But it has lower capacity, due to its internal structure.

10. It is costly since coke has to be graphitized at 2600-3300 0 C