(2ad) Molecular Engineering of Reactive Electrochemical Interfaces

Decarbonization of our future society requires widespread utilization of renewable energy at a global scale. To achieve carbon neutrality, advanced technologies of energy conversion and storage need to be developed to compensate the intermittent nature of renewable energy sources, especially solar and wind. However, one critical challenge hurdling the development of next-generation energy technologies is the reactive nature of electrochemical interfaces for high-energy applications, such as Li metal battery. As conventional electrochemistry studies charge-transfer processes occurring at “clean” electrode surface, the formation of solid-electrolyte interphase (SEI) via active decomposition of electrolyte species leads to a less well documented research area that is highly relevant for enabling high-energy electrochemical devices.

Combining my extensive expertise of fundamental electrochemistry and surface science allows comprehensive elucidation of the elusive correlation between the nanoscale molecular reactivity and the macroscopic behaviors of energy materials. Using Li metal anode (LMA) as an illustration, I have demonstrated the powerful capability of multi-modal X-ray photoelectron spectroscopy (XPS) to uncover both the reaction pathway and formation mechanism of SEI layer at electrode surfaces. These new insights can be further extended into identifying key functional molecular moieties dictating the operational reversibility of LMA. More importantly, the significance of electric double layer (EDL) at the vicinity of Li metal during plating/stripping is emphasized to rationalize the molecular origins of irreversible capacity loss for LMA, especially dead Li. Complex molecular phenomena such as competitive adsorption of anions and pseudocapacitive Li underpotential deposition (Li UPD), are systematically revealed to constitute a versatile molecular engineering toolbox that is foundational to fine tuning both the efficiency and stability of reactive electrochemical interfaces.

Research Interests: Pivoting towards an independent career, my future MoREI laboratory will unlock the full potentials of high-energy applications based on under-explored reactive electrochemical interfaces, operating far beyond the thermodynamic stability window. We will primarily focus on rationally leveraging reactive metals for enabling next-generation rechargeable batteries as well as conventionally challenging chemical-fuel synthesis, with a particular emphasis of rationally designing favorable SEI through molecular engineering. Three directions will be pursued: (a) fundamental understanding of structure-performance relationship in liquid electrolyte mediated by electrochemical reactivity; (b) advanced characterization to elucidate the elusive SEI reaction and formation mechanisms; (c) designing artificial interphases with desirable physical and chemical compatibility to regulate the interfacial reactivity to improve the macroscopic performance.

Teaching Interests: My previous chemistry background as well as chemical-engineering training have allowed me to introduce a mechanism-driven perspective into teaching wide-ranging chemical engineering courses involving principles, thermodynamics and kinetics of chemical reactions. Moreover, my research interests in renewable energy will motivate me to establish new courses related to the fundamental and practical aspects of electrochemical energy technologies, with a great potential of preparing next-generation scientists and engineers to solve grand energy challenges.