Understanding Mixed-Phase Cathode Materials for Sodium-Ion Batteries
Faculty Advisor: Dr. Claire Xiong
The rapid development of electric vehicles and large-scale energy storage systems has increased demand for lithium-ion batteries; however, due to lithium being a limited resource, materials that are less expensive and more abundant remain attractive alternatives. In particular, sodium-ion batteries are a promising supplemental approach to reduce dependence on lithium. Although much progress has been made on sodium-ion chemistries, many structure-property-performance challenges persist. For instance, with the ionic radii of sodium ions (1.02 Å) twenty-five percent larger than lithium ions (0.76 Å), a large mechanical strain at the phase boundary — in the case of sodium-ion cathodes — is expected. Thus, it is crucial to design structurally stable electrodes to reduce the plastic deformation (or phase transformation) during the removal and insertion of sodium ions. Mixed-phased cathode materials with intergrown phases have shown promising structural stability and electrochemical properties. Thus, the goal of this project is to understand the mechanisms of intergrowth phase formation and the effects of processing variables on nucleation and growth of intergrowth phases in mixed-phased cathode materials.
Role of Participant(s):
The participant(s) will be involved in the design and synthesis of advanced Na-ion electrode materials as well as in the characterization of interfaces within the electrodes. They will be trained to characterize the electrode materials via scanning electron microscopy (SEM) and XRD and aid in the further characterization via TEM (transmission electron microscopy). Finally, they will learn to evaluate battery performance by testing electrodes electrochemically in Na half-cells.