Wednesday, 11 September 2024 11:00am – 12:00pm

This seminar will be delivered in Lecture Theatre 2

Speaker: Professor Sarah H. Tolbert

Host: A/Prof. Girish Lakhwani

Title: Applications of Nanoporous Materials – From Batteries to Magnetics

Abstract: In this talk, we explore a number of unique material properties that can be tuned using nanoscale porosity. We begin with materials for electrochemical energy storage (i.e. batteries), focusing on a family of fast charging materials known as pseudocapacitors. When conventional electrode materials are synthesized in nanoporous form, they can be used to produce batteries that charge much faster than those made with conventional bulk materials. This arises because of a very desirable combination of electrical connectivity throughout each porous grain, electrolyte access to the interior of the material, and short solid-state ion diffusion lengths within the walls of the nanoporous network. In some materials, the nanoscale wall dimensions can also suppress intercalation-induced phase transitions, further improving kinetics. Nanoscale porosity can also help increase stability in other battery electrodes, particular those that have large volume changes upon cycling. Focusing on alloy anodes, we show that nanoscale porosity can help mitigate structural degradation due to volume changes. We next consider how nanoporous materials can be used to control the behavior of magnetic materials. Here, we examine multiferroic composites, where ferroelectric and ferromagnetic materials are coupled through strain. Multiferroic composites can be made using a nanoporous magnetic network that is conformally filled with a ferroelectric phase. We find the largest multiferroic response in materials with partly filled pores, indicating that mechanical flexibility is a key performance factor. Finally, if time allows, we will briefly examine how silica based nanoporous materials can be used in passive daytime radiative cooling. Here materials are designed to scatter incoming solar radiation, while emitting strongly in the atmospheric transparency window, resulting in passive cooling.

Bio: Sarah Tolbert is a professor in the Department of Chemistry and Biochemistry at UCLA. Research in her group focuses on self-organized nanoscale materials and includes both organic templated inorganic phases and colloidal materials. Current work in her group is aimed at understanding and controlling structure and periodicity in complex nanostructured composite materials, and in exploiting that periodicity for a range of structural, optical, and electronic materials applications. Professor Tolbert’s honors include a National Science Foundation Early CAREER Development Award, the Office of Naval Research Young Investigator Award, a Beckman Young Investigator Award, and an Alfred P. Sloan Foundation Fellowship.