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Developing Markets for Natural Graphite by George C Hawley
1. 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
2. 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.
3. 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.
4. 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.
5. • 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
6. 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
7. 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
Copyright 2010- George C Hawley &
Associates
9. 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.
10. Energy Storage Applications
Batteries
Lithium Ion Lithium Ion polymer Lithium bromide
Fuel Cell
Flow Battery Bipolar Plates
Supercapacitors
11. 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
12. 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
14. Nuclear Plants – Existing & Future
China China Russia Russia Japan Japan India India World World
Status plants MWe plants MWe plants Mwe Plants Mwe plants Mwe
Jan 2007
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)
Copyright 2010- George C Hawley &
Associates
15. 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.
16. 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.
17. 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)
18. 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.
20. New Possibilities for Graphite Anodes
Capacity, mAh/g
LIC6 372
Li C2.33 900
LiC1.0 2238
21. 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
22. 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
23. 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
24. Selected Properties of Lithium Ion
Battery Anode Materials
Thermal
Density Resistivity,
Material Conductivity
g/cc. Ohm.m
W/m.K
470 10-7-10-6 in basal plane
Graphite 2.26
25 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
25. 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%
26. Comparison of Typical Carbon
Capacities (Enerdel)
Material Initial Reversible Irreversible % First
capacity, capacity, capacity, Cycle
mAh.g mAh.g mAh.g Efficiency
Graphite 390 360 30 92
Hard 480 370 90 77
Carbon
Soft 275 235 40 85
Carbon
Note:
Non –graphitizable hard carbon is made from precursors that
char as they are pyrolized.
27. Chinese Graphite for Lithium Ion
Batteries
Particle
Tap Surface Discharge
size, Fixed
Density, Area Capacity
D50 Carbon, %
g/cc m 2 /g. mAh/g
microns
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.
28. 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.
29. Positive electrodes
Electrode Av. potential Specific capacity, Specific energy,
material difference, volt mA.h/g 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.
30.
31.
32. 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
33. 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
34. 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.
35. 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
36. 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
