Dr. Kingshuk Roy, TCG-CREST, Kolkata

Abstract: 

The promise of sodium metal batteries, particularly anode-less configurations, rests on mastering one deceptively simple event: the first nucleation of sodium on a bare substrate. Yet, this event is governed by a complex web of interfacial kinetics, solvation chemistry, nucleation energetics, and evolving interphases. This talk will present a ground-up exploration of sodium metal anode stability, integrating molecular-level electrolyte behavior, current collector surface chemistry, and spatially modulated ion flux. This talk will begin with probing the interfacial charge transfer kinetics and solvation-desolvation dynamics using fast-scan voltammetry, capturing transient plating behavior in real time. By combining variable-temperature nuclear magnetic resonance, Raman spectroscopy, and several other fundamental material and electrochemical characterization techniques across length and time scales, this talk will help uncover how solvation asymmetry and mobility dictate desolvation energetics and SEI evolution. These insights are distilled into mechanistic descriptors that quantify electrolyte efficacy. Building on this, the talk will also demonstrate how spatially engineered sodiophilic domains engineer sodium ion flux and stabilize deposition morphology. Various degrees of post-cycling in-situ measurements will reveal that edge-localized electric fields and chemical defects can guide uniform plating and suppress dendrites. Together, these findings reframe the problem of Na metal stability; not as a materials limitation, but as an interfacial design challenge, solvable through a unified, multiscale strategy linking molecules to morphology.