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© 2013 Evans Analytical Group
Analytical Methods for Characterizing Battery Materials
NCCAVS, 10th Sept 2013Sanjay Patel
Page 1 of 25
© 2013 Evans Analytical Group 2
• Founded in 1978• Leader in advanced surface analysis and materials
characterization• 700 employees• Locations worldwide
Evans Analytical Group
Page 2 of 25
Analytical Techniques in Other Industries
Page 3 of 25
Commercial Analytical Lab?
Sample Commercial Analytical Lab.
(EAG)
• Fully Confidential – no IP or patent related issues
• Fast turnaround – typically 3-5 days
• Access to best available techniques and procedures
Data Supplied
© 2013 Evans Analytical Group
Page 4 of 25
© 2013 Evans Analytical Group 5
Research and Development
•Accuracy•Lowest detection Limit
•Resolution•Physical / Chemical Information
Manufacturing / Production Control
•Repeatability•Cost•Speed – turnaround time•Sampling
Analytical Considerations
Analytical consideration for R&D and manufacturing differ
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© 2013 Evans Analytical Group 6
Choosing the Analytical Method
0.E+00
1.E+01
2.E+01
3.E+01
4.E+01
5.E+01
6.E+01
7.E+01
8.E+01
9.E+01
1.E+02
Sr Cl Cu V Si
Impu
rity
Leve
l (pp
m w
t%)
Element Measured
R&DMeasurement accuracy important
Manufacturing controlChecking impurity levels are below a critical value
Optimum Technique Selection - Costs
Reduced
Page 6 of 25
7
Bubble Chart for Analytical Techniques
1. Microscopy
2. Surface Analysis
3. Bulk Analysis
© 2013 Evans Analytical Group
Page 7 of 25
Study of SEI
© 2013 Evans Analytical Group 8
TEM, cycled cathode particle
• Small spot size to analyze
individual particles
• Ability to measure elemental and
molecular components
• Shallow information depth (few
nms)
• Depth profiling ability
Analysis of SEI is essential for understanding
electrochemical mechanism which results in
loss of cell performance/cycle life.
Characterization of SEI Requires:
Page 8 of 25
9
Small Area Elemental Analysis
Auger used for imaging LiNiCoMnOcathode particles ~1 micron size particles
© 2013 Evans Analytical Group
A09ZJ63820.spe: M010 80% capacity 20C Generic Electrolyte, Cathode EAG
2009 Dec 3 10.0 keV 0 FRR 2.3051e+005 max 3.34 min
Sur1/Area1/2 (S9D9)
100 200 300 400 500 600 700 800 900 1000
-1
-0.5
0
0.5
1
1.5
2
x 105 A09ZJ63820.spe
Kinetic Energy (eV)
c/s
CP
NiCo
Mn
NiNiCo
Co
MnMn
C
P
O• Typical spot size ~ 50 nm• Li difficult due to poor sensitivity• Elemental analysis• No molecular information
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TEM / EELS
© 2013 Evans Analytical Group 10
TEM
0
10000
20000
30000
40000
50000
60000
0 5 10 15 20
Distance (nm)
Inte
nsity
C
P
O
Fe
EELS Measurement
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11
SEM / EDS
Oxygen mapped by AugerSEM tool
Oxygen mapped by EDS in SEM tool
© 2012 Evans Analytical Group
Source of Auger electron signal
EDS
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12
Bubble Chart for Analytical Techniques
© 2013 Evans Analytical Group
EELS/EDS – elemental analysis during microscopy
Auger – elemental analysis of small areas
XPS – Chemical/molecular information
TOF-SIMSSmall area analysis Molecular informationElemental informationDepth profiling capability
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13
Depth of Analysis / Information Depth
Analysis Depth Variation with Technique
© 2013 Evans Analytical Group
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© 2013 Evans Analytical Group 14
Lithium Titanium Oxide Anode100
80
60
40
20
01007550250μm
Total Ion Image, sample CMC: 24; TC: 1.140e+006
24
20
16
12
8
4
0
TOF-SIMS Imaging Capability
1. Ion Image – can mass select
2. Images recorded as a function
of depth
3. Entire mass spectrum recorded
per pixel – allowing any mass to
be imaged or depth profile
generated at any region
Page 14 of 25
© 2013 Evans Analytical Group 15
Secondary Ion ImageTotal Counts
100
80
60
40
20
01007550250μm
Total Ion Image, Sample AMC: 302; TC: 9.952e+006
280
240
200
160
120
80
40
0
100
80
60
40
20
01007550250μm
Li+ ion image, Sample AMC: 9; TC: 5.721e+005
8
6
4
2
0
Secondary Ion ImageLithium
TOF-SIMS Mass Selection
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Variation in material grade from one supplier to another or even batch to batch (from the same supplier), should be monitored to ensure identical performance of manufactured cells.
Cell Manufacturer
Material Supplier #1
Material Supplier #2
Material Supplier #3
Cells with Identical Performance Manufactured
Cells with Varying Performance Manufactured
Raw Material Control
© 2013 Evans Analytical Group
Page 16 of 25
Understanding Particle Size and Distribution
17
Efficiency and consistency of the slurry mixing process is evaluated by SEM by checking particle distribution and agglomeration
LiFePO4 cathode Graphite based anode
Cathode particles
Carbon black
Anode particles
Carbon black
~300nm size
Cathode
Anode
© 2013 Evans Analytical Group
Page 17 of 25
18
Manufacturing Control of Electrode Materials
© 2013 Evans Analytical Group
Minor Elements (impurity analysis): ICP-MS or GDMS
-GDMS had advantage of measuring all elements in period table rather than a select number of elements as in the case for ICP-MS. -ICP-MS provide better accuracy over GDMS.
Major Elements: ICP-OES
Organic Analysis: GC/MS
Page 18 of 25
Impurity Analysis of LiFePO4
19
Samples A and B: expected to be similar
Samples C, D, E and F: expected to be similar and to have higher levels of vanadium
Samples G and H: from two different overseas suppliers
© 2012 Evans Analytical Group
Study• Eight LiFePO4 batches ready for cell manufacture• Measure impurities
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Elements >0.01 at. Wt%
© Copyright 2013 Evans Analytical Group LLC 20
Unwanted impurities detected e.g. manganese, magnesium etc.
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Sample LFP-H has significantly higher levels of Si, Nb and Ti compared to LFP-A and LFP-B.
© 2013 Evans Analytical Group
Comparison of GDMS Data
21
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This chart shows higher levels of Mn and Mg in LFP-H compared to LFP-A and LFP-B.
© 2013 Evans Analytical Group
Comparison of GDMS Data
22
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Two cells with very different characteristics – made from similar LiFePO4 (according to supplier)
Cell Cycling Data – Performance Variation
© 2013 Evans Analytical Group 23
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Summary
24© 2013 Evans Analytical Group
• Careful choice of analytical technique is essential for improving product development and good manufacturing control.
• Fast “turn-around” with optimized analytical method results in significant cost savings.
• With continued advances in battery materials, the analytical method requires changes/modification based on the material and information required.
Page 24 of 25
Thank You!
25© 2013 Evans Analytical Group
Contact:
Sanjay Patel
480-239-0602
www.eag.com
Page 25 of 25