Valence
Technology
Inc.
A Brief Review of Valence
Technology’s Phosphate
Program (Saphion®)
Valence
Technology
Inc.
Valence Technology Inc.
Where Safety meets Power
by
12201 Technology Blvd., Suite 150,
Austin, Texas, 78727, USA
Jerry Barker and Yazid Saidi
Pure ™
PO4WER
Pure ™
PO4WER
ICMAT2007: 4th International Conference on Materials for
Advanced Technologies 2007, July 1-6, 2007, Singapore
ICMAT2007: 4th International Conference on Materials for
Advanced Technologies 2007, July 1-6, 2007, Singapore
Introduction- Valence Technology Inc.
Valence
Technology
Inc.

Valence Technology Inc. has been working on
Phosphate Active materials since the early 1990’s
Specialists in Electrochemical and Solid-State
Chemistry

Has built up a large portfolio of lithium and sodium
active materials – phosphates, condensed phosphates,
fluorophosphates and other polyanions (100+ patents on
active materials)
www.jerrybarker.co.uk

Valence needed a cost-effective and scalable process for
synthesizing these materials at a commercial level

Developed the Carbothermal Reduction (CTR) method
for the preparation of active materials

Today Valence makes all its active materials using this
CTR approach – at up to Metric Tonne/day scale
Jerry Barker Consultants
Pure ™
PO4WER
ICMAT2007: 4th International Conference on Materials for
Advanced Technologies 2007, July 1-6, 2007, Singapore
Valence
Technology, Inc.
ICMAT2007, Singapore
July 1-7, 2007
Why Phosphates?
Discharge Voltage (V)
Discharge Characteristics of Phosphate Materials
Vanadium Phos. (LVP)
Iron Phos. blend
Vanadium Fluorophos. (LVPF)
Cobalt Phosphate
5.0
4.0
3.0
2.0
0
100
200
300
400
500
600
Cathode Material Specific Energy (Wh/kg)
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Technology, Inc.
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1
Why Phosphates: DSC on Charged Cathodes
800
600
400
Carbothermal
Reduction
200
0
LFP
LVPF
LVP
LCP
Exotherm (J/g)
Heat Flow (J/gr)
1000
LMO
LCO
LNO
LNO 893 J/g
LCO 570
LMO 335
LFP 124 J/g
100
200
Temperature (C)
300
400
Theoretical basis for safety advantages of phosphates
Valence
Technology, Inc.
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Technology, Inc.
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Carbothermal Reduction (CTR)

Free Energy or Ellingham Diagrams
2C + O2  2 CO = increase in volume and therefore entropy. Carbon is
unique in that CO free energy of formation becomes increasingly negative as
the temperature increases – i.e. more stable at high temperatures.
Implications: Carbon can reduce any oxide provided a high enough
temperature can be reached. Example: Na extraction:
Top: Low affinity for oxygen – easy
to reduce; Bottom: High affinity for
oxygen – difficult to reduce
Na2CO3 (liquid) + 2 C (solid) → 2 Na (vapor) + 3 CO (gas)

Carbothermal Reduction (CTR) technique utilizes an in-situ reducing agent
while leaving behind an embedded conductive network.

Carbon monoxide formed during the high temperature synthesis both
promotes further reduction and deposits carbon “nanoparticles”

Net result: precursor carbon is finely distributed throughout and on surface of
final product.
Determines the relative ease of
reducing of a given metallic oxide to
the metal using carbon
Determines the partial pressure of
oxygen that is in equilibrium with a
metal at a given temperature
C + O2  CO2
2 C + O2  2 CO
Valence
Technology, Inc.
But it tells us nothing about the
kinetics of these reactions
Valence
Technology, Inc.
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Iron Blast Furnace
Fe2+/3+
Fe2+
Fe0

Process „borrowed‟ from the Extractive Metallurgy Industry

Uses a particulate carbon to „reduce in‟ the metal ion.

Potential for use with cheap precursors (Fe 2O3, V2O5, EMD etc)

Residual carbon forms a highly conductive composite product

Use same carbon as typical in Electrode Formulations (Super P)

Valence Technology uses CTR to make all its active materials – at up to
the Metric Tonne/day scale.

Examples:
Take Home Message:
Intermediate oxidation states:




ICMAT2007, Singapore
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Characteristics of Carbothermal Reduction
Reaction Mechanisms:
3 Fe2O3 + CO  2 Fe3O4 + CO
Fe3O4 + CO  3 FeO + CO2
FeO + CO  Fe + CO2
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3 LiH2PO4 + V2O5 + C  Li3V2(PO4)3 + 3 H2O + CO
Fe3+  Fe2+
Mn3+  Mn2+
V5+  V3+
Mo6+  Mo4+ etc.
LiH2PO4 + 0.5 Fe2O3 + 0.5 C  LiFePO4 + H2O + 0.5 CO
LiH2PO4 + 0.5 Mn2O3 + 0.5 C  LiMnPO4 + H2O + 0.5 CO
0.5 V2O5 + (NH4)2HPO4 + C  VPO4 + 2 NH3 + H2O + 0.5 CO
Valence
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2
CTR: A Schematic Representation
SEM of Carbothermal Material
lithium salt
Before reaction: Mixture of carbon,
metal oxide, phosphate and lithium salts
Metal
Oxide
The CO produced promotes
reduction while residual carbon
remains as carbon “nanoparticles”
Metal
Oxide
carbon
Lithium Metal Phosphate
starts to form as the oxide
is reduced
Lithiated
Metal
Phosphate
Net result: as the product is
formed, precursor carbon is
distributed throughout and on
surface of final product
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Valence
Technology, Inc.
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Technology, Inc.
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SEM of Carbothermal Material
-LiV2O5
0.5 Li2CO3 + 0.5 V2O5 + 0.5 C  LiV2O5 + 0.5 CO2 + 0.5 CO
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Life Cycling of Li // -LiV2O5
Li//-LiV2O5
C/5 Rate, 2.80-3.80 V
4.0
400
3.5
3.0
2.5
2.0
1.5
1.0
0.5
150
Specific Discharge Capacity
(mAhr/g)
500
Differential Capacity, dQ/dV [C/V]
+
Electrode Potential [V vs. Li/Li ]
x in LixV2O5
1.0 0.9 0.8 0.7 0.6 0.5 0.4 0.3 0.2 0.1 0
4.5
0
300
200
Extraction
100
0
-100
Insertion
-200
-300
-400
0
25
50
75
100
ICMAT2007, Singapore
July 1-7, 2007
125
150
Cathode Specific Capacity [mAh/g]
-500
1.0
1.5
2.0
2.5
3.0
3.5
4.0
+
Electrode Potential [V vs. Li/Li ]
125
100
75
23C
60C
50
25
0
0
100
200
300
400
500
600
Cycle #
J. Barker et al. J. Electrochem. Soc.150, A1267, (2003)
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3
Graphite//-LiV2O5
4.5
2000
4.0
1500
Differential Capacity, dQ/dV [C/V]
3.5
Cell Voltage [V]
3.0
2.5
2.0
1.5
1.0
Charge
500
0
-500
Discharge
-1000
LiH2PO4 + 0.45 Fe2O3 + 0.1 Mg(OH)2 + 0.45 C
 LiFe0.9Mg0.1PO4 + 1.1 H2O + 0.45 CO
-1500
0.5
0
LiFe(Mg)PO4
1000
0
25
50
75
100
125
150
-2000
1.0
Cathode Specific Capacity [mAh/g]
1.5
2.0
2.5
3.0
3.5
4.0
Cell Voltage [V]
J. Barker et al. J. Electrochem. Soc.150, A1267, (2003)
Valence
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Li//LiFe1-xMgxPO4
Olivine - LiFe1-xMgxPO4
 Fe and Mg occupy the same
crystallographic position
 Controlled morphology and
particle size give rise to fast
electrode kinetics
 150-170 mAh/g @ 3.45 V vs. Li
 Metric Tonne production
4.5
800
4.0
600
3.5
Electrode Potential [V vs. Li]
 Framework comprises PO4
tetrahedra and MO6 octahedra
Differential Capacity, dQ/dV [C/V]
 3- Dimensional Framework
Structure
3.0
2.5
2.0
1.5
1.0
0
20 40 60 80 100 120 140 160
Cathode Specific Capacity [mAh/g]
Valence
Technology, Inc.
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200
0
-200
-400
-600
0.5
0
400
-800
1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5
Electrode Potential [V vs Li]
Valence
Technology, Inc.
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Capacity
Graphite//LiFe1-xMgxPO4 – 18650 cycling
110
100
90
80
70
60
50
40
30
20
10
0
Li3V2(PO4)3
3 LiH2PO4 + V2O5 + C  Li3V2(PO4)3 + 3 H2O + CO
0
100
200
300
400
500
600
700
800
900 1000 1100
Cycle
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4
Structure of Li3V2(PO4)3
Li//Li3V2(PO4)3
 Three distinct crystallographic
sites for Li+
 High Li ion mobility gives rise to
fast insertion kinetics
5.0
300
4.5
250
4.0
200
Differential Capacity, dQ/dV [C/V]
 Framework comprises PO4
tetrahedra and slightly distorted
MO6 octahedra
Electrode Potential [V vs. Li]
 3- Dimensional Framework
Structure
3.5
3.0
2.5
2.0
1.5
1.0
All 3 Li ions extractable
generating a specific capacity close
to theoretical (197 mAh/g)
0.5
0
150
100
50
0
-50
-100
-150
0
50
100
150
200
Cathode Specific Capacity [mAh/g]
-200
2.5
3.0
3.5
4.0
4.5
5.0
Electrode Potential [V vs Li]
Acknowledgements: Profs. Goodenough, Delmas, Gopalakrishnan
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Technology, Inc.
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Graphite//Li3V2(PO4)3
5
Valence
Technology, Inc.
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Li3V2(PO4)3 Lithium-ion cells: Cycling
250
200
4
Differential Capacity, dQ/dV [C/V]
184 mAh/g
Cell Potential [V]
167 mAh/g
3
2
1
150
100
50
0
-50
-100
0
0
50
100
150
200
Cathode Specific Capacity [mAh/g]
-150
2.0
2.5
3.0
3.5
4.0
4.5
5.0
Cell Potential [V]
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Fluorophosphate - LiVPO4F
 Framework Triclinic Structure
related to the minerals, Amblygonite
LiAlPO4F and Tavorite LiFePO4OH
LiVPO4F
 Structure comprises a 3D
framework built up from PO4
tetrahedra and MO4F2 octahedra
 Representation left is shown
along the c-axis
0.5 V2O5 + (NH4)2HPO4 + C  VPO4 + 2 NH3 + H2O + 0.5 CO
 V located in the MO4F2 octahedra
LiF + VPO4  LiVPO4F
 Electrochemistry suggests 2 sites
for the Li ions
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5
Li//LiVPO4F
Refined XRD Data for LiVPO4F (Triclinic)
5.0
300
4.5
a = 5.1658(8)Å
b = 5.3034(8)Å
c = 7.4945(2)Å
 = 66.917(8)o
 = 66.994(7)o
 = 81.619(9)o
Cell vol. = 173.85(5) Å3
200
Differential Capacity, dQ/dV [C/V]
Electrode Potential [V vs. Li]
4.0
3.5
3.0
2.5
2.0
1.5
1.0
100
0
-100
-200
0.5
0
0
-300
2.5
20 40 60 80 100 120 140 160
Cathode Specific Capacity [mAh/g]
3.0
3.5
4.0
4.5
5.0
Electrode Potential [V vs Li]
Theoretical Capacity - 155 mAh/g Reversible Specific Capacity!!
Valence
Technology, Inc.
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Graphite//LiVPO4F
5.0
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LiVPO4F vs. LCO: Lithium-ion Cells
5.0
300
4.5
4.5
200
Cell Voltage [V]
3.5
3.0
2.5
2.0
1.5
1.0
100
0
-100
4.06 V
3.76 V
3.5
LiCoO2
3.0
2.5
2.0
1.5
1.0
-200
0.5
0.5
0
LiVPO4F
4.0
RCB Cell Voltage [V]
Differential Capacity, dQ/dV [C/V]
4.0
ICMAT2007, Singapore
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0
20 40 60
80 100 120 140 160
Cathode Specific Capacity [mAh/g]
-300
2.0
0
2.5
3.0
3.5
4.0
4.5
5.0
0
2
4
6
Cell Voltage [V]
8
10
12
140 mAh/g Reversible Specific Capacity!!
Valence
Technology, Inc.
14
16
18
Time on Test [h]
J. Barker et al. Solid State Ionics 177, 2635, (2006)
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LiVPO4F Lithium-ion cells: Cycling
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LiVPO4F Lithium-ion cells: Latest Cycling
Cathode Specific Capacity [mAh/g]
160
140
120
100
80
60
40
20
0
0
20
40
60
80
100
120
140
160
180
200
Cycle Number
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6
Fluorophosphate - Na3V2(PO4)2F3
 Framework Tetragonal Structure
built up from [PO4] tetrahedra and
[VO4F2] bi-octahedra with bridging
Fluorine.
Na3V2(PO4)2F3
 Representation left is shown
along the a-axis
V in the MO4F2 octahedra
 Electrochemistry suggests 3 sites
for the Na ions
0.5 V2O5 + (NH4)2HPO4 + C  VPO4 + 2 NH3 + H2O + 0.5 CO
3 NaF + 2 VPO4  Na3V2(PO4)2F3
J. Barker et al. Solid State Ionics 177, 1495, (2006)
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Refined Structure - Na3V2(PO4)2F3
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Li//Na3V2(PO4)2F3
5.0
40
4.5
30
Differential Capacity, dQ/dV [C/V]
Electrode Potential [V vs. Li]
4.0
3.5
3.0
2.5
2.0
1.5
1.0
20
10
0
-10
(b)
-20
(a)
0.5
0
0
20 40 60 80 100 120 140 160 180
Cathode Specific Capacity [mAh/g]
-30
2.5
3.0
3.5
4.0
4.5
5.0
Electrode Potential [V vs Li]
Simple Analytical Tool: weigh the cathode!
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Li//Na3V2(PO4)2F3
5.0
40
4.5
Differential Capacity, dQ/dV [C/V]
Electrode Potential [V vs. Li]
3.5
3.0
2.5
2.0
1.5
1.0
20
10
0
-10
-20
-30
0.5
0
Novel Battery
Applications
30
4.0
0
20
40
60
80 100 120 140
Cathode Specific Capacity [mAh/g]
Valence
Technology, Inc.
-40
2.5
3.0
3.5
4.0
4.5
5.0
Electrode Potential [V vs Li]
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Alternate Cell Configurations
LITHIUM-ION
Graphite / Li electrolyte / Li cathode
Symmetrical
Lithium-ion Cells
SYMMETRICAL LITHIUM-ION
LiVPO4F / Li electrolyte / LiVPO4F
SODIUM-ION
Hard Carbon / Na electrolyte / Na cathode
HYBRID-ION
Graphite / Li electrolyte / Na Cathode
Valence
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Symmetrical LiVPO4F Lithium-ion Cells
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Li//LiVPO4F - Dual Plateau Behavior
Concept
5
Use the same active material as both anode and cathode
150
100
Simplicity of manufacture and use (single electrode coating)
Intrinsically safe: bullet-proof technology
Very low cost
Ideally suited for large format applications
Bi-polar: Charge in either direction
Differential Capacity, dQ/dV [C/V]
Electrode Potential [V vs. Li]
4
3
2
1
50
0
-50
-100
-150
-200
0
-200-150-100 -50
Anode = Cathode = LiVPO4F: 150 mAh/g
0
50 100 150 200
Cathode Specific Capacity [mAh/g]
Electrolyte: 1M LiPF6 in EC/DMC
-250
0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0
Electrode Potential [V vs. Li]
J. Barker et al. Electrochem. Solid-State Chem. 8, A285, (2005)
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LiVPO4F//LiVPO4F Lithium-ion Cells
3.0
200
150
Differential Capacity, dQ/dV [C/V]
RCB Potential [V]
2.5
2.0
1.5
1.0
100
Sodium-ion Cells
50
0
-50
-100
160
-150
0.5
0
0
20 40 60 80 100 120 140 160
Cathode Specific Capacity [mAh/g]
-250
0.5
1.0
1.5
2.0
2.5
RCB Potential [V]
3.0
3.5
Cathode Specific Capacity [mAh/g]
140
-200
120
100
80
60
40
20
0
J. Barker et al. Electrochem. Solid-State Chem. 8, A285, (2005)
Valence
Technology, Inc.
0
10
20
30
40
50
60
70
Cycle Number
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8
Sodium-ion Batteries
Sodium-ion: Hard Carbon/Na+/Na3V2(PO4)2F3
Concept
5
5
4
4
Cell Voltage [V]
An enabling technology
Energy Density similar to lithium-ion
Anode: Hard carbon
Cell Voltage [V]
Sodium-ion: A safer/cheaper alternative to lithium-ion technology?
3
2
1
82 mAh/g
79 mAh/g
3
78 mAh/g
2
1
Electrolyte: 1M NaPF6 in EC/DMC
0
0
Cathode: Na insertion material
10
20
30
40
50
60
70
80
90
0
100
0
50
Cumulative Cathode Specific Capacity [mAh/g]
100
150
200
250
300
Cumulative Specific Capacity [mAh/g]
Anode Reaction: Reversible Na+ insertion
J. Barker et al. Electrochem. Solid-State Chem. 6, A1, (2003)
Cathode Reaction: Reversible Na+ insertion
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Hybrid-ion Batteries
Concept
Hybrid-ion: An enabling technology - many new cell chemistries
Key Feature: Fully lithiated graphite is stable in a Na electrolyte
Hybrid-ion Cells
Anode: Graphite (but can also use e.g. Li4Ti5O12)
Electrolyte: 1M LiPF6 in EC/DMC
Cathode: Na+ insertion material
Anode Reaction: Reversible Li+ insertion
Cathode Reaction: Reversible Na+ insertion (initially)
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Hybrid-ion: Graphite /Li+/Na3V2(PO4)2F3
5.0
140
Cathode Specific Capacity [mAh/g]
Differential Capacity, dQ/dV [C/V]
20
Cell Voltage [V]
4.0
3.5
3.0
2.5
2.0
10
0
-10
-20
1.5
0
20
40
60
80
100 120 140
Cathode Specific Capacity [mAh/g]
-30
2.5
3.0
3.5
4.0
4.5
5.0
120
C/2 Rate
2C Rate
100
80
60
40
20
0
0
Cell Voltage [V]
J. Barker et al. Electrochem. Solid-State Chem. 9, A190, (2006)
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Hybrid-ion: Graphite /Li+/Na3V2(PO4)2F3
30
4.5
1.0
Valence
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20
40
60
80
100
120
Cycle Number
J. Barker et al. Electrochem. Solid-State Chem. 9, A190, (2006)
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Hybrid-ion: Li4Ti5O12/Li+/Na3V2(PO4)2F3
Hybrid-ion: Li4Ti5O12/Li+/Na3V2(PO4)2F3
5.0
140
3.5
80
3.0
60
Cathode Specific Capacity [mAh/g]
Na3V2(PO4)2F3
4.5
Differential Capacity, dQ/dV [C/V]
4.0
2.5
3.0
Cell Voltage [V]
Electrode Potential [V vs. Li]
3.5
2.5
2.0
2.0
1.5
1.0
1.5
40
20
0
-20
-40
Li4Ti5O12
0.5
1.0
0
0.5
-60
0
25
50
75
100
125
150
Cathode Specific Capacity [mAh/g]
0
0
25
50
75
100
125
150
175
-80
1.0
1.5
2.0
2.5
3.0
120
Li Eelectrolyte
100
2Na/1Li Electrolyte
80
60
40
20
3.5
Cell Voltage [V]
0
200
Active Material Specific Capacity [mAh/g]
Valence
Technology, Inc.
40
60
80
100
Cycle Number
ICMAT2007, Singapore
July 1-7, 2007
Other Phosphates – but no time to mention!!
Valence
Technology, Inc.
ICMAT2007, Singapore
July 1-7, 2007
Summary: Phosphates for Lithium-ion
Both sloping and flat discharge profiles are possible
 Li2MPO4F (US#6810686 + others)
depending on the metal combinations and structure.
Carbothermal Reduction – low cost processing, scalable
 Na2MPO4F (US#6810686 + others)
Through the use of preparative methods exceptional life
 LiVPO4.OH (US#6777132)
cycling and high rate performance may be attained.
 LiVP2O7
Phosphate materials have demonstrated superior safety
characteristics.
 β-LiVOPO4
Applicability into new battery chemistries: sodium-ion,
 New Active Phosphate Phases – ca.150 mAh/g, 4
V vs. Li average, sloping and flat voltage profiles
Valence
Technology, Inc.
20
ICMAT2007, Singapore
July 1-7, 2007
hybrid-ion, symmetrical lithium-ion etc.
Valence
Technology, Inc.
ICMAT2007, Singapore
July 1-7, 2007
Thank you for your
attention!
www.valence.com
www.jerrybarker.co.uk
Valence
Technology, Inc.
ICMAT2007, Singapore
July 1-7, 2007
10