Exploratory Synthesis of Plyanion-Based Open-Framework Solids As Potential Candidates For Cathode Material Applications

Author

Adam Siegfried, Clemson UniversityFollow

Date of Award

5-2008

Document Type

Thesis

Degree Name

Master of Science (MS)

Legacy Department

Chemistry

Committee Chair/Advisor

Hwu, Shiou-Jyh

Committee Member

Pennington , William T

Committee Member

Smith , Rhett C

Abstract

This thesis is concerned with exploratory synthesis of polyanion based open-framework solids that can potentially be used as cathode materials in lithium batteries. Two silver manganese vanadates were discovered, Ag₃Mn(VO₄)₂ and AgMn₂V₃O₁₀, which show different possibilities as cathode materials for primary battery applications; the former contains a higher (Ag+Mn)/V ratio, which is sought for high capacity devices, while the latter may prove better for lower power devices. The structures of the two materials differ in that Ag₃Mn(VO₄)₂ is a layered material where as AgMn₂V₃O₁₀ possesses a one-dimensional channel along the c axis.
These materials were synthesized under vacuum in fused silica tubes after the starting materials were ground together and heated to 600 ¡C for three days and then slowly cooled to 300 ¡C. This synthetic route is different than previous cathode materials, which typically have been synthesized by hydrothermal techniques. By utilizing high temperature methods employed within this thesis, thermodynamic rather than kinetic products are formed, which are important for high temperature battery applications.
Also described is a non-centrosymmetric (NCS) cesium cobalt phosphate, Cs₂Co₂O(P₂O₇) which is characterized by a three-dimensional channel framework in which cesium ions reside. KCrAs₂O₇ and RbCrAs₂O₇ were synthesized in molten-salt media, and the crystal structures exhibit a three-dimensional channel framework as well. The magnetic and electronic properties of these three materials are discussed in detail. On the basis of the bond distances and local geometry with respect to the ion-transport of electropositive cations in the channel framework, these materials show potential as ion-exchange materials.

Recommended Citation

Siegfried, Adam, "Exploratory Synthesis of Plyanion-Based Open-Framework Solids As Potential Candidates For Cathode Material Applications" (2008). All Theses. 367.
https://tigerprints.clemson.edu/all_theses/367