Type
Text
Type
Thesis
Advisor
Khalifah, Peter G | Marschilok, Amy C. | Hsiao, Benjamin S
Date
2017-05-01
Keywords
Chemistry
Department
Department of Chemistry
Language
en_US
Source
This work is sponsored by the Stony Brook University Graduate School in compliance with the requirements for completion of degree.
Identifier
http://hdl.handle.net/11401/77068
Publisher
The Graduate School, Stony Brook University: Stony Brook, NY.
Format
application/pdf
Abstract
Phosphate based ceramics are widely used in the field of energy materials, where they have been used both as solid state ionic conductors and as electrode materials. Two kinds of phosphate based ceramics: NASICONs (Na Super Ion Conductors) and alpha-cristobalite form AlPO4 were synthesized and analyzed in this work. Phosphate based NASICONs materials, which have the general formula: A3 xM2(PO4)3, represent the first known family of Na superionic conductors, and for this reason, have found use as solid state electrolytes. More recently, lithium-substituted NASICON-structured materials have been identified as candidate electrolytes for solid state lithium ion batteries. Various approaches for the synthesis of NASICON-type compounds Li1.5Al0.5Ti1.5(PO4)3 and Na1.5Al0.5Ti1.5(PO4)3 were pursued in this work. A variety of experimental conditions (different reaction containers, different reaction atmospheres, different reaction precursors, etc.) were tried to overcome limitations of the high reactivity of samples with crucibles during synthesis procedures. X-ray diffraction techniques were used to identify and quantify product and impurity phases. A second phosphate based ceramic material investigated in the course of this work is AlPO4 with the alpha-cristobalite structure. It is known that SiO2 with the alpha-cristobalite structure is a rare example of a ceramic with a negative Poisson’s ratio. Polycrystalline alpha-cristobalite AlPO4 was synthesized to investigate whether this predicted behavior can indeed be observed. Although the many phase transitions between different polymorphs of AlPO4 complicate the synthesis of the desired alpha-cristobalite form, good methods for preparing dense pellets of this phase were developed. | Phosphate based ceramics are widely used in the field of energy materials, where they have been used both as solid state ionic conductors and as electrode materials. Two kinds of phosphate based ceramics: NASICONs (Na Super Ion Conductors) and alpha-cristobalite form AlPO4 were synthesized and analyzed in this work. Phosphate based NASICONs materials, which have the general formula: A3 xM2(PO4)3, represent the first known family of Na superionic conductors, and for this reason, have found use as solid state electrolytes. More recently, lithium-substituted NASICON-structured materials have been identified as candidate electrolytes for solid state lithium ion batteries. Various approaches for the synthesis of NASICON-type compounds Li1.5Al0.5Ti1.5(PO4)3 and Na1.5Al0.5Ti1.5(PO4)3 were pursued in this work. A variety of experimental conditions (different reaction containers, different reaction atmospheres, different reaction precursors, etc.) were tried to overcome limitations of the high reactivity of samples with crucibles during synthesis procedures. X-ray diffraction techniques were used to identify and quantify product and impurity phases. A second phosphate based ceramic material investigated in the course of this work is AlPO4 with the alpha-cristobalite structure. It is known that SiO2 with the alpha-cristobalite structure is a rare example of a ceramic with a negative Poisson’s ratio. Polycrystalline alpha-cristobalite AlPO4 was synthesized to investigate whether this predicted behavior can indeed be observed. Although the many phase transitions between different polymorphs of AlPO4 complicate the synthesis of the desired alpha-cristobalite form, good methods for preparing dense pellets of this phase were developed. | 41 pages
Recommended Citation
Zhao, Yiran, "Synthetic Studies of Phosphate Based Ceramic Materials" (2017). Stony Brook Theses and Dissertations Collection, 2006-2020 (closed to submissions). 2905.
https://commons.library.stonybrook.edu/stony-brook-theses-and-dissertations-collection/2905