Title

Faulted Structures in Li Ion Exchanged NaMO2 (M=Ni(0.25)Mn(0.75))

Author

Aaron M. DeWahl, Michigan Technological University

Date of Award

2013

Document Type

Master's Thesis

Degree Name

Master of Science in Materials Science and Engineering (MS)

College, School or Department Name

Department of Materials Science and Engineering

Advisor

Stephen A Hackney

Abstract

A family of LiMO2 materials (M=Ni_0.25Mn_0.75) was prepared from Na_1.2-xLi_xMO_∂ precursors (0≤x≤0.6) via ion exchange. The resulting IE products were examined via XRD and compared to simulated XRD patterns produced using DIFFax to determine the defect structures resulting from the IE process. For the 0.1≤x≤0.6 materials, it is observed that there are 3 LiMO₂ sub-phases with different Li contents present. As the amount of Li in the precursor increases, the amount of each phase changes resulting in a net shift to higher 2-theta; corresponding to an overall decrease in lattice parameter, approaching the theoretical values for LiMO₂. Additionally, as x increases, the probability of O3-type shifting increases, most likely due to an increase in the amount O3-Li₂MO₃ minority phase which acts to weaken bonds in the TM layer, allowing the O3 shift to occur more easily. For the x=0 IE product, it was seen that the product had an ~O2-type structure, but with lattice parameters closer to those expected for a NaMO₂ material.

Recommended Citation

DeWahl, Aaron M., "Faulted Structures in Li Ion Exchanged NaMO2 (M=Ni(0.25)Mn(0.75))", Master's Thesis, Michigan Technological University, 2013.

https://doi.org/10.37099/mtu.dc.etds/486