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

Introduction

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.

Critical Problems in Charge Dynamics

In this regime lie:

1. The individual electronic/structural steps in the redox chain that can cause electrode capacity loss via charge-transfer to inactive/unstable states.
2. (De)solvation processes that inhibit fast charging through chemical imbalances at electrode/electrolyte interfaces.
3. Sluggish ionic hops limiting the use of many solid-electrolyte and electrode materials.

Project Overview

In 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.

Objectives

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 interfaces.
3. Use lattice vibrations to manipulate ion-hopping in solid electrodes/electrolytes.

Expected Outcomes

I 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 characterizing 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.