Probing and controlling ultrafast electron and ion dynamics in operating battery electrodes and interfaces

Charge dynamics lie at the crux of electrochemical energy devices, and in-particular batteries, impacting everything from durability to capacity. On mesoscopic time (ns to s) and length scales (nm to mm) we have a good understanding of charge transport related phenomena in batteries. However, when it comes to faster femtosecond/picosecond processes and those at nanoscopic interfaces, our insight remains limited. This is a critical problem. In this regime lie:(a)the individual electronic/structural steps in the redox chain that can cause electrode capacity loss via charge-transfer to inactive/unstable states(b)(de)solvation processes that inhibit fast charging through chemical imbalances at electrode/electrolyte interfaces(c)sluggish ionic hops limiting the use of many solid-electrolyte and electrode materialsIn FemtoCharge, I will take the conceptual leap needed to elucidate ultrafast interfacial dynamics in batteries, by merging femtosecond spectroscopy/microscopy and operando battery science. My novel approach is based on my pioneering work to optically image ultrafast spatio-temporal dynamics, and their coupling to structure, in nanomaterials, and probing in the complex solid/liquid environment of batteries. I will leverage this approach to: 1.uncover optimal electronic/structural pathways for charge-transport in current and developing electrode materials 2.quantitatively reveal potentials and solvation mechanisms at electrode/liquid electrolyte interfaces3.use lattice vibrations to manipulate ion-hopping in solid electrodes/electrolytesI will deliver blueprints for building new electrode/electrolyte battery materials, strategies for external stimuli-based tuning of battery charge-transport and game-changing operando tools for characterising charge-dynamics, particularly when they are stochastic or deeply buried. Ultimately, the fundamental insights and new techniques of FemtoCharge will make controlling charges the future of electrochemistry.