Doctoral Dissertations

Abstract

"Nanoporous carbons (NCs) have become increasingly popular in various fields of research due to their unique properties including tunable pore sizes, higher pore volumes and higher surface areas, as well as being able to produce controlled nanostructures. The work presented here uses NC scaffolds with as active hosts for (1) Li-ion battery electrodes and (2) confined metal hydrides (MH) for hydrogen storage applications. In (1) we investigate the Li diffusion characteristics in hard carbons (HCs) that are important for electrochemical applications. We develop a novel method named Voltage-Relaxation Galvanostatic Intermittent Titration Technique (VR-GITT). Parameters derived from the fitting of electrochemical data provide both the diffusion constants as well as morphological information about the diffusion geometry. The VR-GITT method also allows determination of the diffusion constant in the two-phase region of many materials, where the standard GITT method fails. In (2) it is already known that confining MHs in NCs. can alter the kinetics of de/re-hydriding reactions. We investigate the effects of changing the surface electron density in these HCs by the addition of nitrogen (N). The various chemical environments for the surface nitrogens include pyridinic and pyrrolic. The pyridinic N contains a lone pair of electrons that should be available to form Lewis-acid/base complexes that interact with confined MHs, and provide a favorable (wetting) surface energy for incorporation of AlH3, LiBH4, and other hydrides into the carbons. Our results indicate that both B and Al interact with these pyridinic Ns upon introduction to the HCs. The infiltration of LiBH4 is straightforward, while the infiltration of AlH3 requires oxygen reduction techniques during the carbon scaffold synthesis"--Abstract, page iv.

Advisor(s)

Majzoub, Eric H.
Yamilov, Alexey

Committee Member(s)

Fraundorf, Philip
Holmes, Stephen M.
Medvedeva, Julia E.

Department(s)

Physics

Degree Name

Ph. D. in Physics

Sponsor(s)

University of Missouri Research Board
Hydrogen Materials Advanced Research Consortium (HyMARC)
United States Department of Energy Office of Energy Efficiency and Renewable Energy Fuel Cell Technologies Office
Sandia National Laboratories
Honeywell International Inc
United States National Nuclear Security Administration

Comments

This work was partially supported by funds from the Research Board Award from the University of Missouri. The authors gratefully acknowledge research support from the Hydrogen Materials Advanced Research Consortium (Hy- MARC), established as part of the Energy Materials Network under the U.S. Department of Energy, Office of Energy Efficiency and Renewable Energy, Fuel Cell Technologies Office, under Award Number DOE - EE0007656.

This dissertation is a presented to the faculty of the graduate school of the Missouri University of Science and Technology and University of Missouri-St. Louis in partial fullfilment of the requirements for the degree of Doctor of Philosophy in Physics.

Publisher

Missouri University of Science and Technology

Publication Date

Fall 2018

Journal article titles appearing in thesis/dissertation

  • Novel voltage-relaxation GITT and Monte Carlo to determine lithium diffusion and distribution in TiO2 and highly-ordered nanoporous hard carbons
  • AlH3 and LiBH4 confined in N-containing carbon scaffolds: A computational and experimental study

Pagination

xii, 180 pages

Note about bibliography

Includes bibliographic references.

Rights

© 2018 Waruni Jayawardana, All rights reserved.

Document Type

Dissertation - Open Access

File Type

text

Language

English

Thesis Number

T 11423

Electronic OCLC #

1084473125

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Included in

Physics Commons

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