Spatially resolved ionic measurements with scanning electrochemical microscopy

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.

Name thesis:degree_name

Ph.D.

Level thesis:degree_level

Dissertation

Discipline thesis:degree_discipline

Chemistry

Grantor

University of Illinois at Urbana-Champaign

Year dc:date

2017

Author dc:creator

• Barton, Zachary James

Contributors dc:contributor

• Rodríguez-López, Joaquín
• Gewirth, Andrew A.
• Leckband, Deborah E.
• Flaherty, David W.

• Scanning electrochemical microscopy (SECM)
• Li-ion battery

Statement dc:rights

• Copyright 2017 Zachary James Barton

Language dc:language

en

Handle dc:identifier

http://hdl.handle.net/2142/98113

OAI identifier oai:identifier

oai:www.ideals.illinois.edu:2142/98113