Improved performance of alkaline batteries via magnetic modification and voltammetric detection of

227 Pages·2017·7.41 MB·English

University of Iowa
Iowa Research Online
Theses and Dissertations
Summer 2012
Improved performance of alkaline batteries via
magnetic modification and voltammetric detection
of breath acetone at platinum electrodes
Perry Nelson Motsegood
University of Iowa
Copyright 2012 Perry Motsegood
This dissertation is available at Iowa Research Online: https://ir.uiowa.edu/etd/4883
Recommended Citation
Motsegood, Perry Nelson. "Improved performance of alkaline batteries via magnetic modification and voltammetric detection of
breath acetone at platinum electrodes." PhD (Doctor of Philosophy) thesis, University of Iowa, 2012.
https://doi.org/10.17077/etd.fqqvtunx
Follow this and additional works at:https://ir.uiowa.edu/etd
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IMPROVED PERFORMANCE OF ALKALINE BATTERIES VIA MAGNETIC
MODIFICATION AND VOLTAMMETRIC DETECTION OF BREATH
ACETONE AT PLATINUM ELECTRODES
by
Perry Nelson Motsegood
An Abstract
Of a thesis submitted in partial ful(cid:133)llment
of the requirements for the Doctor of
Philosophy degree in Chemistry
in the Graduate College of
The University of Iowa
July 2012
Thesis Supervisor: Associate Professor Johna Leddy
1
ABSTRACT
Incorporation of magnetic microparticles ( 1 (cid:22)m) at electrode structures
(cid:24)
increases electron transfer e¢ ciency, observed as increased current, for multiple
electrochemical systems. Current increases occur with magnetic (cid:133)eld. Inclusion
of magnetic materials into the cathode matrix of alkaline MnO batteries requires
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the materials to be stable in the strong base electrolyte, typically 6 to 9 M KOH.
Samarium cobalt magnetic particles sustain strong permanent magnetic (cid:133)elds and
are stable in base without surface modi(cid:133)cation. Studies were undertaken at fast
(C/2), moderate (C/3), and slow (C/5) constant current discharges.
Here, alkaline MnO batteries generated increased power and energy when
2
magnetic microparticles are incorporated into the cathode of the battery. Because
of anode limitations in the battery, total coulombic output is not increased for
the (cid:133)rst electron discharge, but the available power and energy is signi(cid:133)cantly
higher compared to nonmagnetic batteries at voltages above 0.9V. Constant current
discharge curves of magnetic batteries demonstrate higher voltages than nonmagnetic
batteries at a given time, which translates to greater power output. This e⁄ect
is also observed by electrochemical impedance spectroscopy, where charge transfer
resistance is less for magnetically modi(cid:133)ed cells.
This work also developed voltammetric measurement protocols for acetone
concentration collected in the liquid and vapor phase and measured in solution.
Acetone on the breath is an indicator for physiological dysregulation. Measurements
are demonstrated for acetone concentrations across the human physiological range,
1 (cid:22)M to 10 mM at platinum electrodes in 0.5 M H SO . E⁄ects arise through
2 4
2
adsorption of acetone from the gas phase onto a platinum surface and hydrogen
in acidic solution within the voltammetric butter(cid:135)y region. The protocol is
demonstrated to yield breath acetone concentration on a human subject within the
physiological range and consistent with ketone urine test strip.
Abstract Approved:
Thesis Supervisor
Title and Department
Date
IMPROVED PERFORMANCE OF ALKALINE BATTERIES VIA MAGNETIC
MODIFICATION AND VOLTAMMETRIC DETECTION OF BREATH
ACETONE AT PLATINUM ELECTRODES
by
Perry Nelson Motsegood
A thesis submitted in partial ful(cid:133)llment
of the requirements for the Doctor of
Philosophy degree in Chemistry
in the Graduate College of
The University of Iowa
July 2012
Thesis Supervisor: Associate Professor Johna Leddy
Copyright by
PERRY NELSON MOTSEGOOD
2012
All Rights Reserved
Graduate College
The University of Iowa
Iowa City, Iowa
CERTIFICATE OF APPROVAL
PH.D. THESIS
This is to certify that the Ph.D. thesis of
Perry Nelson Motsegood
hasbeenapprovedbytheExaminingCommitteeforthethesis
requirementfortheDoctorofPhilosophydegreeinChemistry
at the July 2012 graduation.
Thesis Committee:
Johna Leddy, Thesis Supervisor
Mark A. Arnold
Edward G. Gillan
Claudio J. Margulis
Michelle M. Scherer
Always bear in mind that your own resolution to
succeed is more important than any other thing.
Abraham Lincoln
(cid:24)
OR
Success is not (cid:133)nal, failure is not fatal:
it is the courage to continue that counts.
Winston Churchill
(cid:24)
ii
ACKNOWLEDGMENTS
I would like to ardently thank Prof. Johna Leddy for her guidance and
encouragment to transform a horrible situation into a new opportunity. Without
her, I probably would have left The University of Iowa and never have earned the
opportunities I now face. I would like to acknowledge the undergraduate students
who worked on the battery project: Jen Augello, Jessica Jewett, Jacob Robbins, and
Darren Youngs. Recognition goes to Nate Coleman and Andrew Zimmerman for
their conversations and assistance with SEM and XRD data acquisition. Gratitude
is expressed toward Prof. Petr Vanysek (Northern Illinois University Department
of Chemistry) for conversations and instruction on impedance spectroscopy.
Resounding thanks goes to the Leddy Group as a whole and speci(cid:133)cally toward
fellow departmental graduate students Tim Paschkewitz, Mike Ivanov, David
Rotsch, Arundhuti Sen, and Kreso Bucar for their friendship and support during
my graduate career. For (cid:133)nancial assistance, The University of Iowa Graduate
College, National Science Foundation, and GM Nameplate (Seattle, WA) are greatly
appreciated.
I would like to humbly thank my entire family, especially my wife Jennifer. It is
by her grace, patience, and support that I am able to achieve this goal. Finally, to
my children Aleksander and Natalia for making me laugh and being a continuous
reminder of why this is important.
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TABLE OF CONTENTS
LIST OF TABLES ................................................................vii
LIST OF FIGURES............................................................... ix
CHAPTER
1. INTRODUCTION ............................................................. 1
1.1 Alkaline Batteries.......................................................... 1
1.1.1 Basic Electrochemistry Of Zn MnO Battery ....................... 2
2
j
1.1.2 Magnetic Field E⁄ects on Electrochemical Systems................. 4
1.1.3 Self Exchange Reactions ............................................ 4
1.2 Acetone Detection on Human Breath...................................... 5
1.2.1 Brief history ........................................................ 5
1.2.2 Conventional Detection Techniques................................. 6
1.2.3 Electrochemical Acetone Reduction on Platinum ................... 6
2. ALKALINE BATTERY SYSTEMS AND MAGNETIC PROPERTIES........ 8
2.1 Alkaline Battery Electrochemistry......................................... 8
2.1.1 Cell Voltage......................................................... 9
2.1.2 Battery Capacity ..................................................10
2.1.3 Discharge Current (C rate)........................................11
2.1.4 Energy versus Power...............................................12
2.2 Magnetic Impacts on Electrochemical Systems ...........................13
2.2.1 Dahms Ru⁄Model.................................................17
2.3 MnO Allotropes and Lattice Structures .................................19
2
2.3.1 Pyrolusite..........................................................19
2.3.2 Ramsdellite ........................................................19
2.3.3 Nsutite and Electrolytic MnO ....................................21
2
2.3.4 Magnetic Susceptibility ............................................21
2.4 Experimental .............................................................22
2.4.1 Materials...........................................................22
2.4.2 Powder X-ray Di⁄raction ..........................................23
2.4.3 Scanning Electron Microscopy .....................................24
2.4.4 Battery Assembly Procedure.......................................24
2.5 Techniques................................................................32
2.5.1 Chronopotentiometry ..............................................32
2.5.2 Impedance Spectroscopy...........................................33
2.5.3 Summary of Statistical Tests ......................................36
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