Doctoral Dissertations

Keywords and Phrases

Atomic Layer Deposition; Cathode; Conductive Films; Lithium-Ion Battery; Nanostructured Materials; Thin Film Coating

Abstract

"Atomic/molecular layer deposition (ALD/MLD) has emerged as an important technique for depositing thin films in both scientific research and industrial applications. In this dissertation, ALD/MLD was used to create novel nanostructures for two different applications, catalysis and lithium-ion batteries.

MLD was used to prepare ultra-thin dense hybrid organic/inorganic polymer films. Oxidizing the hybrid films removed the organic components and produced the desired nanoporous films. Both porous alumina and titania films can be prepared by such a way. A novel nanostructured catalyst (Pt/SiO2) with an ultra-thin porous alumina shell obtained from the thermal decomposition of an aluminium alkoxide film deposited by MLD for size-selective reactions was developed. The molecular sieving capability of the porous metal oxide films was verified by examining the liquid-phase hydrogenation of n-hexene versus cis-cyclooctene.

For lithium-ion battery cathodes, two different approaches are presented. Firstly, ultrathin and highly-conformal conductive CeO2 films were coated on LiMn2O4 particles using ALD process. The initial capacity of the 3 nm CeO2-coated sample showed 24% increment compared to the capacity of the uncoated one, and 96% and 95% of the initial capacity was retained after 1,000 cycles with 1C rate at room temperature (RT) and 55 ⁰C, respectively. The study of ionic and electronic conductivities of the coated and uncoated materials helped explain the improved performance of CeO2 coated materials. Secondly, iron oxide films were deposited using ALD on LiMn1.5Ni0.5O4 particles for the synergetic effect of performance enhancing by iron doping and conformal iron oxide film coating. With an optimal film thickness of ~0.6 nm, the initial capacity improved by 25% at RT and by ~26% at 55 ⁰C at 1C cycling rate. The synergy of doping of LiMn1.5Ni0.5O4 with Fe near surface combined with the conductive and protective nature of the optimal iron oxide film led to high capacity retention (~93% at RT and ~91% at 55 ⁰C) even after 1,000 cycles at 1C cycling rate"--Abstract, page iv.

Advisor(s)

Liang, Xinhua

Committee Member(s)

Al-Dahhan, Muthanna H.
Park, Joontaek
Rezaei, Fateme
Choudhury, Amitava

Department(s)

Chemical and Biochemical Engineering

Degree Name

Ph. D. in Chemical Engineering

Sponsor(s)

National Science Foundation (U.S.)
Missouri University of Science and Technology. Materials Research Center
University of Missouri Research Board

Comments

This work was supported in part by the National Science Foundation grant NSF CBET 1402122.

Publisher

Missouri University of Science and Technology

Publication Date

Summer 2016

Journal article titles appearing in thesis/dissertation

  • Highly porous titania films coated on sub-micron particles with tunable thickness by molecular layer deposition in a fluidized bed reactor
  • Encapsulation of supported metal nanoparticles with an ultra-thin porous shell for size-selective reactions
  • Significant capacity and cycle-life improvement of lithium-ion batteries through ultrathin conductive film stabilized cathode particles
  • Ionic and electronic conductivities of thin atomic layer deposited film coated lithium-ion battery cathode particles
  • Employing synergetic effect of doping and thin film coating to boost the performance of lithium-ion battery cathode particles

Pagination

xiii, 161 pages

Note about bibliography

Includes bibliographic references.

Rights

© 2016 Rajankumar Patel, All rights reserved.

Document Type

Dissertation - Open Access

File Type

text

Language

English

Thesis Number

T 11353

Electronic OCLC #

1041856673

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