Redox Processes and Materials Design for Lithium-Oxygen & Redox-Flow Batteries

Yi-Chun Lu*

The Chinese University of Hong Kong 

Abstract: Energy storage system is a critical enabling factor for deploying unstable and intermittent renewable power sources such as solar and wind power sources. Energy storage devices including lithium-oxygen (Li-O2) and flow batteries have received extraordinary attention owing to their attractive energy density and flexibility in scaling power and energy. In this presentation, we will discuss fundamental redox processes and design strategies in Li-O2 and redox flow systems. We exploit various spectroscopic techniques coupled with single-cell electrochemical characterizations to probe the battery reactions. We use rotating-ring disk electrode (RRDE) and online electrochemical mass spectrometry (OEMS) to investigate the influences of solvent and redox mediator on the stability of Li-O2 batteries. Interactions between multiple redox-active species are studied and exploited to achieve higher energy density with enhanced stability in flow system. We will discuss the cycling stability of these multiple redox systems and the synergistic interactions in improving the energy and reversibility of the batteries. The influence of flow rate and current density on the electrochemical performance under a continuous flow mode will also be discussed.

Biography: Prof. Yi-Chun Lu received her Ph.D. degree in Materials Science & Engineering from the Massachusetts Institute of Technology in 2012. She is currently an Assistant Professor in the Department of Mechanical and Automation Engineering at The Chinese University of Hong Kong (CUHK). She was the recipient of the Hong Kong SAR Research Grants Council Early Career Award (2014), Young Researcher Award (2016), University Education Award, (2016), Vice-Chancellor's Exemplary Teaching Award (2014). Prof. Lu's research interest centers on developing fundamental understandings and material design principles for clean energy storage and conversion. Specifically, her research group is studying: Electrode and electrolyte design for high-energy metal-air and metal sulfur batteries; Redox-active components and solution chemistry for redox-flow batteries. Electrocatalysts and electrode design for low-temperature fuel cells and electrolyzers; Mechanistic understanding of interfacial phenomena governing electrochemical energy conversion and storage processes.