Rising Stars Colloquium: Layla Mehdi

Understanding and Controlling the Kinetics of Nanoscale Processes in Li-Ion Batteries using Operando Scanning Transmission Electron Microscopy

Dr B. Layla Mehdi 1,2

1Engineering & Physical Sciences, University of Liverpool, Liverpool L69 3GH, UK 2

Physical and Computational Science Directorate, PNNL, Richland, WA 99352, USA

The global demand for clean energy to power all aspects of society’s current and future needs in transportation, industrial processes and our homes has created a critical need for improved, energy storage systems with both higher energy densities and high-power capabilities. Advancing new energy storage systems is one of the major scientific and technological challenges of our time, and requires the development and implementation of new battery electrode nanomaterials as well as high stability liquid/solid electrolytes, in a manner that also permits a circular economy to be developed – recycling Li-ion batteries is a major challenge in itself. Systems currently under development are complex multi-scale devices where the fundamental storage process of ion transport across the electrode/electrolyte interface is controlled by the kinetics of diffusion, which can be radically different from one part of the interface to the next. Fortunately, atomic scale imaging methods in operando scanning transmission electron microscopy (STEM) allow the dynamic structural changes and processes that occur locally at the electrode/electrolyte interface to be imaged directly while a nanoscale battery is operating in the microscope. In this presentation, I will focus on the use of Operando STEM to analyse Li-ion batteries and understand the molecular level interactions occurring as a function of key industrial parameters: cycling efficiency, side reactions, anode stability, controlled formation of a solid-electrolyte interphase (SEI) layer and wide range of dynamic phase transformations occurring in Ni-rich cathodes. In addition, I will discuss new imaging methods currently under development to improve our understanding even further, and demonstrate how they can be applied to beyond Li-ion energy storage technologies and many other materials challenges in the future.

Bio: Dr Mehdi is currently an Assistant Professor in the School of Engineering and Associate Director of the Albert Crewe Centre for Electron Microscopy at the University of Liverpool. She received her undergraduate and Master's degree in Chemistry from the University of Warsaw, Poland and her PhD in Chemistry from the Miami University, USA. Following her PhD, she joined the Pacific Northwest National Laboratory (PNNL), USA as a Postdoctoral Research Associate and was then promoted to a staff scientist. Her work at PNNL involved the development of Operando TEM stages to study dynamic processes in Li-ion batteries as part of the Department of Energy’s Joint Centre for Energy Storage Research (JCESR). She has over eight years of experience in the development and application of in-situ methods in electron microscopy for which she has received numerous awards. These include the 2019 Albert Crewe Award from the Microscopy Society of America MSA for distinguished contributions to the field of Microscopy and Microanalysis in the Physical Sciences by an Early Career Scientist, a 2015 MRS Postdoctoral Award, a 2015 Microscopy Society of America postdoctoral award, a 2014 Microscopy and Microanalysis Presidential award, and the 2013 Miami University award for outstanding Ph.D. work. Additionally, in 2016 she received a JSPS Postdoctoral Fellowship to preform Research at the Nagoya University, Japan in collaboration with Toyota. At Liverpool, she is currently a principal investigator of the UK Faraday Institution’s Battery Challenge for “Degradation” and “Characterisation” projects.