2015 william arthur paxton all rights reserved

106 Pages·2015·5.56 MB·English

by  William Paxton

©2015
WILLIAM ARTHUR PAXTON
ALL RIGHTS RESERVED
IN-SITU AND OPERANDO CHARACTERIZATION OF BATTERIES WITH ENERGY-
DISPERSIVE SYNCHROTRON X-RAY DIFFRACTION
By
WILLIAM ARTHUR PAXTON
A dissertation submitted to the
Graduate School-New Brunswick
Rutgers, The State University of New Jersey
In partial fulfillment of the requirements
For the degree of
Doctor of Philosophy
Graduate Program in Materials Science and Engineering
Written under the direction of
Thomas Tsakalakos
And approved by
_____________________________________
_____________________________________
_____________________________________
_____________________________________
New Brunswick, New Jersey

January 2015
ABSTRACT OF THE DISSERTATION
In-situ and Operando Characterization of Batteries with Energy-Dispersive Synchrotron
X-ray Diffraction
By WILLIAM ARTHUR PAXTON

Dissertation Director:
Thomas Tsakalakos

Batteries play a pivotal role in the low-carbon society that is required to thwart the effects
of climate change. Alternative low-carbon energy sources, such as wind and solar, are often
intermittent and unreliable. Batteries are able capture their energy and deliver it later when it is
needed. The implementation of battery systems in grid-level and transportation sectors is
essential for efficient use of alternative energy sources.
Scientists and engineers need better tools to analyze and measure the performance
characteristics of batteries. One of the main hindrances in the progress of battery research is
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that the constituent electrode materials are inaccessible once an electrochemical cell is
constructed. This leaves the researcher with a limited number of available feedback mechanisms
to assess the cell’s performance, e.g., current, voltage, and impedance. These data are limited in
their ability to reveal the more-localized smaller-scale structural mechanisms on which the
batteries' performance is so dependent.
Energy-dispersive x-ray diffraction (EDXRD) is one of the few techniques that can internally
probe a sealed battery. By analyzing the structural behavior of battery electrodes, one is able to
gain insight to the physical properties on which the battery’s performance is dependent. In this
dissertation, EDXRD with ultrahigh energy synchrotron radiation is used to probe the electrodes
of manufactured primary and secondary lithium batteries under in-situ and operando
conditions. The technique is then applied to solve specific challenges facing lithium ion batteries.
Diffraction spectra are collected from within a battery at 40 micrometer resolution. Peak-
fitting is used to quantitatively estimate the abundance of lithiated and non-lithiated phases.
Through mapping the distribution of phases within, structural changes are linked to the
battery’s galvanic response. A three-dimensional spatial analysis of lithium iron phosphate
batteries suggests that evolution of inhomogeneity is linked to the particle connectivity. Despite
a non-linear local response, the average of the measured ensemble behaves linearly. The results
suggest that inhomogeneity can be difficult to measure and highlights the power of the EDXRD
technique. Additional applications of EDXRD are discussed.

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Acknowledgements
Getting a PhD was something that I never originally thought I could do. In retrospect though,
embarking on this journey was one of the best decisions I have ever made. While getting a PhD
may seem like an individual pursuit, the process requires the contribution of and support by
many. In the end, there are many people whom I should acknowledge.
First, I should acknowledge all the great scientists whose names appear in the references
sections of this dissertation. Organizing one’s work and communicating it in a publication format
can be an arduous task and yet it is essential for the progress of science. I am, thus, grateful for
all of those who have written before me, making it possible for me to “stand on their
shoulders.”
Second, I should acknowledge my adviser, Tom Tsakalakos, for his tireless dedication to his
students. I consider myself extremely lucky to have had his support from the beginning. I am
also extremely grateful for Lisa Klein who has always been available for encouragement and
advice throughout the process. Additionally, the advice and support of Glenn Amatucci, Vassilis
Keramidas, and K.C. Lim is gratefully acknowledged. My work at Brookhaven wouldn’t have
been successful without the knowledge of the beamline master Zhong Zhong. Another person
whom I attribute to the “Brookhaven-experience” is Koray Akdoğan; I will always think back to
the many enlightening discussions we had there.
I have special gratitude for İlyas Şavkliyildiz and Brandon Berke for showing me the ropes in
the research group. I owe a lot to the coding mastery of Scott Silver, Wu Yi, Ankur Choksi, and
Hui Zhong. Their hard effort has saved me, and other EDXRD researchers, time and frustration.
Additionally I would like to thank all the rest of my cohort for making this experience more
colorful: Hülya Biçer, Tevfik Ozdemir, Shivani McGee. My graduate experience wouldn’t have
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been the same without getting to know and working with Bart Visser. Our many discussions
about science, life, and nature will always be remembered.
Certainly, I owe so much to my family for supporting me along the path of life: my parents,
Helen and Art Paxton; my sisters, Emma and Daria Paxton; my grandparents, Mary and David
Sive, Dorothy and Norman Paxton. Lastly, I thank all my friends, old and new, who make my life
all the much richer.
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Table of Contents
Acknowledgements......................................................................................................................... iv
List of Figures .................................................................................................................................. ix
List of Tables .................................................................................................................................... x
1. Introduction ............................................................................................................................. 1
1.1 Motivation............................................................................................................................ 1
1.2 Literature Review ................................................................................................................. 3
1.3 Scope of Work ...................................................................................................................... 5
1.4 References ........................................................................................................................... 6
2. Technical Background .............................................................................................................. 8
2.1 Lithium-Ion Batteries ........................................................................................................... 8
2.2 Diffraction Background ...................................................................................................... 10
2.3 Synchrotron Radiation ....................................................................................................... 12
2.4 Energy-Dispersive X-ray Diffraction ................................................................................... 14
2.5 The Application to Lithium-Ion Batteries ........................................................................... 17
2.6 Data Collection ................................................................................................................... 19
2.6.1 Tomographic Profile ............................................................................................... 19
2.6.2 Diffraction Spectra ................................................................................................. 20
2.6.3 Peak Shape Analysis ............................................................................................... 21
2.7 References ......................................................................................................................... 24
3. Tracking inhomogeneity in high-capacity lithium iron phosphate batteries ......................... 25
3.1 Preface ............................................................................................................................... 25
3.2 Graphical Abstract ............................................................................................................. 25
3.3 Highlights ........................................................................................................................... 25
3.4 Abstract .............................................................................................................................. 26
3.5 Introduction ....................................................................................................................... 26
3.6 Experimental ...................................................................................................................... 29
3.6.1 Electrochemical cells .............................................................................................. 29
3.6.2 Energy-dispersive x-ray diffraction ........................................................................ 30
3.6.3 Stoichiometric determination ................................................................................ 31
3.6.4 Measurement strategy .......................................................................................... 32
3.7 Results and discussion ....................................................................................................... 33
3.7.1 Depth profiling ....................................................................................................... 35
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3.7.2 In-plane profiling .................................................................................................... 37
3.8 Conclusions ........................................................................................................................ 40
3.9 Acknowledgements ............................................................................................................ 40
3.10 References ......................................................................................................................... 40
4. Asynchronous stoichiometric response in lithium iron phosphate batteries ........................ 43
4.1 Preface ............................................................................................................................... 43
4.2 Abstract .............................................................................................................................. 43
4.3 Introduction ....................................................................................................................... 44
4.4 Experimental ...................................................................................................................... 46
4.5 Results and Discussion ....................................................................................................... 49
4.6 Concluding Remarks........................................................................................................... 58
4.7 Acknowledgements ............................................................................................................ 59
4.8 References ......................................................................................................................... 60
4.9 Supplemental Figures ........................................................................................................ 62
5. Additional Data ...................................................................................................................... 64
5.1 Preliminary evidence for inhomogeneity .......................................................................... 64
5.2 CR2032 and BR2032 Coin Cells .......................................................................................... 67
5.2.1 Preface ................................................................................................................... 67
5.2.2 Electrochemical Cells ............................................................................................. 67
5.2.3 Slit settings ............................................................................................................. 68
5.2.4 Data analysis .......................................................................................................... 68
5.2.5 Results and Discussion ........................................................................................... 68
5.2.6 Further reading ...................................................................................................... 75
6. Summary and Future Work .................................................................................................... 76
Appendix A. Tools for Data Analysis .............................................................................................. 79
A.1 CNF Converter .................................................................................................................... 79
A.2 Peak Fitting: Fityk ............................................................................................................... 79
A.3 Batch Peak Fitting Script .................................................................................................... 80
A.4 Lattice Parameter Calculator ............................................................................................. 80
A.5 Time Stamp Extractor ........................................................................................................ 80
Appendix B. Anisotropic thermal expansion of zirconium diboride .............................................. 82
B.1 Preface ............................................................................................................................... 82
B.2 Abstract .............................................................................................................................. 82
B.3 Introduction ....................................................................................................................... 83
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B.4 Experimental ...................................................................................................................... 84
B.5 Results and Discussion ....................................................................................................... 86
B.6 Conclusions ........................................................................................................................ 94
B.7 Acknowledgements ............................................................................................................ 94
B.8 References ......................................................................................................................... 95

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List of Figures
Figure 2.1 Schematic of a typical lithium ion battery [2] ................................................................ 9
Figure 2.2 Two-dimensional representation of Ewald's Sphere ................................................... 10
Figure 2.3 Bragg diffraction from a cubic crystal lattice ............................................................... 12
Figure 2.4 Sample synchrotron spectra ......................................................................................... 13
Figure 2.5 Schematic of the EDXRD apparatus used at the NSLS beamline X17B1 ....................... 15
Figure 2.6 Geometry of gauge volume .......................................................................................... 16
Figure 2.7 Typical construction of a lithium-ion polymer cell [7] .................................................. 17
Figure 2.8 Orientation of diffraction vectors ................................................................................. 18
Figure 2.9 Gauge volume positioning within electrode layers ..................................................... 19
Figure 2.10 Sample data from an EDXRD experiment .................................................................. 20
Figure 2.11 Screenshot from peak-fitting software fityk .............................................................. 22
Figure 3.1 Energy-dispersive synchrotron x-ray diffraction .......................................................... 31
Figure 3.2 Internal phase mapping and structural information .................................................... 34
Figure 3.3 Operando electrode mapping ....................................................................................... 36
Figure 3.4 Spatial inhomogeneity while discharging .................................................................... 39
Figure 4.1 Experimental configuration of the X17B1 beamline at NSLS. ...................................... 47
Figure 4.2 Summary of the characterization capabilities of energy-dispersive x-ray diffraction as
they relate to lithium-ion batteries. .............................................................................................. 51
Figure 4.3 The cell potential as a function of capacity obtained when discharging the cell. ....... 52
Figure 4.4 Time evolution of the iron phosphate mole fraction as a function of position (depth)
in the electrode layer. .................................................................................................................... 53
Figure 4.5 Mole fraction of FePO and LiFePO4 phases at the position which is centrally located
4
in the electrode. ............................................................................................................................. 55
Figure 4.6 Waterfall plot of the 9 spectra collected in a fixed position at 242 μm, which is
approximately the center of the electrode depth. ........................................................................ 56
Figure 4.7 Scanning electron micrograph of the positive electrode. ............................................ 57
Figure 4.8 A tomographic profile of the battery is produced by plotting the total scattered
intensity as a function of position. ................................................................................................ 62
Figure 4.9 Phase map contour plots for each time point. ............................................................. 63
Figure 5.1 Locations measured in topological study ..................................................................... 64
Figure 5.2 Topological variation of state of charge for two batteries ........................................... 66
Figure 5.3 EDXRD spectra of both lithiated and non-lithiated MnO ............................................ 69
2
Figure 5.4 Li MnO depth profiles ................................................................................................. 70
x 2
Figure 5.5 EDXRD spectra of both CF and LiF+C phases ............................................................... 71
x
Figure 5.6 Depth profiles of LiF phase .......................................................................................... 72
Figure 5.7 Phase maps of MnO2 (CR2032) cells ........................................................................... 73
Figure 5.8 Phase maps of CFx (BR2032) cells ................................................................................ 74
Figure B.1 Schematic of the EDXRD experiment ........................................................................... 86
Figure B.2 Lattice constant a as a function of temperature .......................................................... 88
Figure B.3 Lattice constant c as a function of temperature .......................................................... 89
Figure B.4 Temperature dependence of coefficient of thermal expansion .................................. 92
Figure B.5 Diffraction spectra ........................................................................................................ 93
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