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Title:Spatially resolved ionic measurements with scanning electrochemical microscopy
Author(s):Barton, Zachary James
Director of Research:Rodríguez-López, Joaquín
Doctoral Committee Chair(s):Rodríguez-López, Joaquín
Doctoral Committee Member(s):Gewirth, Andrew A; Leckband, Deborah E; Flaherty, David W
Department / Program:Chemistry
Degree Granting Institution:University of Illinois at Urbana-Champaign
Subject(s):Scanning electrochemical microscopy (SECM)
Li-ion battery
Abstract:Modern electrochemical energy storage systems operate by the concerted shuttling of electrons and cations between a cathode and an anode. Strategies for looking at this process do not have a direct measure of ion movement as it occurs, and thus do not provide essential mechanistic details for optimizing battery performance. This work pioneers the use of Hg-based probes to address this gap in knowledge. First, I show the collection of Li+ over an electrified interface and characterize the linear response of Hg-based signals to changes in ion concentration. To improve the sensing strategy, I then develop a framework and model extracting position and reactivity information from cyclic voltammetry scanning electrochemical microscopy (CV-SECM) and associated methods. This maximizes spatial resolution of substrate ionic reactivity while also minimizing threats to the integrity of the probe. I then improve the sensing platform, delineating a reproducible protocol for generating Hg disc-well probes and providing side-by-side performance comparisons between the new and old probe geometries. Following this, I demonstrate the utility of CV-SECM methods and Hg disc-well probes by separating ionic activity from solid electrolyte interphase (SEI) development processes at an operating model battery anode. Ongoing and future applications for the probes and methods generated by this research include multi-ion measurements, cathode studies, and localized charge–discharge experiments to inform the rational design of the next generation of energy storage materials.
Issue Date:2017-06-13
Rights Information:Copyright 2017 Zachary James Barton
Date Available in IDEALS:2017-09-29
Date Deposited:2017-08

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