Betar Gallant, Professor of Mechanical Engineering, Massachusetts Institute of Technology
11:00 PM PT
This event is free and open to the public.
In coming decades, society must undergo an unprecedented transition from fossil energy to one based increasingly on renewable electricity coupled to chemical transformations. In pursuit of this vision, our research is developing advanced materials and chemistries that underlie near- and longer-term electrochemical storage technologies for clean power and mobility. First, I will describe our efforts to increase the energy density of today's rechargeable batteries for electric vehicles by enabling the lithium (Li) metal anode, a long-sought ‘Holy Grail' that has faced significant hurdles since the early days of Li-based technology. These issues arise from the instability of the fragile, nanoscale solid electrolyte interphase (SEI), which causes Li to suffer from poor reversibility, curtailed cycle life and safety issues, and for which rational design principles are still being sought. I will describe our efforts to develop novel methodologies to study the Li interface and discuss how these approaches are elucidating new insights regarding its chemistry, material properties and function. Such insights are collectively informing powerful strategies to develop better interfaces through electrolyte and additive design. In addition, at the cell level, the high energy density of Li anodes is further realized when combined with high-energy cathodes. In the second part of my talk, I will describe our efforts pioneering a new class of cathode conversion chemistry that harnesses reactivity of ultra-high-energy fluorinated gas or liquid reactants, reaching exceptionally high numbers of electron transfers (exceeding 8 e-/molecule). These efforts have identified compelling motifs for making safer, high-energy primary batteries in the near term, and underpin ongoing efforts to bring these emergent chemistries into the realm of rechargeability in the longer term. Underlying our approach is a continued drive to master electrochemical transformations at the molecular and nanoscales, which is central for unlocking needed device-scale performances.