The shift to a low carbon economy will require wide-scale deployment of energy storage technologies. Breakthroughs in battery materials with higher energy density and longer cycle life will enable greater integration of intermittent renewable generation (like wind and solar PV) and accelerate the adoption of electric mobility. Analytical chemistry plays a central role in understanding the composition, structure and performance of those materials that will fuel the energy transition. In this symposium we will present recent advances in in-situ and operando analytical techniques used to probe electrochemical processes under operationally-relevant conditions, yielding fundamental insights into phenomena that impact how these materials function.