A large proportion of the function of batteries arises from the electrodes, and these are in turn mediated by the atomic-scale perturbations or changes in the crystal structure during an electrochemical process (e.g. battery use). A range of researchers have applied operando and in situ diffraction to probe electrode crystal structure evolution during electrochemical processes inside fully functioning batteries. This allows the direct correlation of structural, electrochemical and external parameters, e.g. atomic site occupancies, applied current and temperature, which provides a relatively holistic picture of electrode function.

This talk is divided into two parts, the first delving into the history of operando/in situ diffraction based techniques used to study lithium-ion batteries, encompassing X-ray, neutron and electron diffraction. I will highlight selected developments, recent breakthroughs, and key considerations required for carrying out these studies, including but not limited to cell design and choice of instrument. The second part of the talk will showcase our recent work in this space, trying to push the boundaries of these experiments. Here we are exploring aspects such as battery types with a range of form factors, i.e., thin-film to large format, the influence of temperature whilst performing in situ experiments, long term in situ experiments and particularly pertinent to applications the high-current rate behaviour of electrodes and their relationship to structural evolution or stability.

The presentation will provide a critical snapshot of how operando and in situ diffraction methods ar contributing to the development of lithium-ion batteries.