The City College of New York
Chemical Engineering Department
PRESENTS

Professor  Craig B. Arnold
Department of Mechanical and Aerospace Engineering, Princeton University

Department: Chemical Engineering
Date & Time: Mon, Sep 21,  14:00 
Location: Steinman Hall - T312
Topic: TBA

ABSTRACT

 Current trends in device technology, particularly in the fields of large area and flexible electronics, are creating a need for new types of mechanically robust energy storage devices with high cycle life and capacity. In such cases, the electrochemical performance is sensitive to the structural and mechanical properties of the internal materials. The ability to characterize and control these aspects provides an important direction for optimization in such systems. In this presentation we will examine two model systems; metal oxide supercapacitors and rechargeable lithium ion batteries with the goal of understanding the relationship among structure, processing, mechanical properties and electrochemical performance. In the case of supercapacitors, we show the use of a large-area laser-based printing technique able to produce distributed devices on flexible platforms. We employ this method to modify and control ionic transport properties in the material and demonstrate that it is possible to optimize the multiscale structure for high rate performance. In the case of batteries we characterize the accommodation of external compressive stress in the cell and how it affects the thermodynamic properties of these flexible systems. We find that changes in the open circuit potential with stress depend on the initial charge state of the cell and the corresponding crystal structure. Furthermore, we find the observed strain response under both a cyclic and static applied loading are indicative of polymer viscoelasticity and can be quantitatively modeled by a 3 parameter Kelvin-Voigt model.