Unlocking the full potentials of renewable energy calls for advanced technologies of energy conversion and storage. Photo-electrochemistry by semiconductor electrode can achieve one-step conversion of solar energy into chemical fuels, while its practical application is limited by long-term durability. Switching from graphite to Li-metal anode can double the energy density of state-of-art Li battery but cause rapid capacity fading upon cycling. Unifying my extensive expertise in Surface and Interface Sciences enables a fundamental look at the nature of Interphase-confined Electrochemistry (ICE) that is urgently necessary to break through the persisting challenges of emerging energy technologies.
My PhD thesis at Caltech has delivered three key mechanisms for understanding the stability of semiconductor photoelectrodes for solar fuels. First, accelerating catalytic kinetics of fuel-forming reactions can suppress corrosion pathways at semiconductor surface that are competitive but less favored by thermodynamics. Also, their photo-electrochemical behaviors are sensitive to altered surface stoichiometry producing unfavorable surface states. Architectural integrity is equally significant for multi-layered solar-fuel devices where corrosion of specific functional layer can cause individual failure mode.
To follow, my postdoc works at Stanford is bridging a knowledge gap from interfacial electrolyte reactivity to the formation of solid-electrolyte interphase (SEI) at Li metal anode (LMA). By innovating X-ray photoelectron spectroscopy (XPS), I managed to reveal underlying electron-transfer pathways causing electrolyte breakdown, and its kinetic dependence on thermodynamic driving force. These fundamentals of SEI chemistry further illustrate the dynamic assembly of passivating layer against dissolution.
During my PhD at Caltech, I also extensively collaborated with Prof. Harry B. Gray and Dr. Nathan Dalleska on analytical verification of N2-reduction electrocatalysis. We established a new protocol of isotopic quantification of ammonia with low detection-limit and high sensitivity.
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