Charge Photometry—A High-Throughput Tool for Operando Studies of Battery Electrodes

In this talk I will introduce Charge Photometry, a technique we have recently established [1-3]. Charge photometry is a optical light scattering microscopy technique that visualizes state-of-charge changes in individual active particles during battery cycling. It exploits the principles of optical interference reflection microscopy to detect scattered light from the active particles. Ion insertion and extraction in the active particles give rise to changes in the detected optical contrast, reporting on the local state-of-charge. Critically, this universal principle means that the charge photometry is agnostic to the underlying battery chemistry and can be applied to a wide range of materials.<br/><br/>I will show examples of how Charge Photometry can be used to gain insights into the mechanisms on charge and discharge within single particles or across the electrode, the nature of phase changes at the single particle level, determine rates of ion diffusion at the single-particle level, monitor degredation of eletrodes down to the singlet particles level and understand electrode-level charge heterogeneity between active particles.<br/><br/>[1] “Operando optical tracking of single-particle ion dynamics and phase transitions in battery electrodes”, Alice J. Merryweather, Christoph Schnedermann, Quentin Jacquet, Clare P. Grey, Akshay Rao, <b><i>Nature, </i></b>594, 522–528, 2021, DOI: 10.1038/s41586-021-03584-2<br/>[2] “Operando monitoring of single-particle kinetic state-of-charge heterogeneities and cracking in high-rate Li-ion anodes”, Alice J. Merryweather, Quentin Jacquet, Steffen P. Emge, Christoph Schnedermann, Akshay Rao, Clare P. Grey, <b><i>Nature Materials</i></b>, 2022, DOI: 10.1038/s41563-022-01324-z<br/>[3] “Operando visualisation of kinetically-induced lithium heterogeneities in single-particle layered Ni-rich cathodes”, Chao Xu, Alice J. Merryweather, Shrinidhi S. Pandurangi, Zhengyan Lun, David S. Hall, Vikram S. Deshpande, Norman A. Fleck, Christoph Schnedermann, Akshay Rao, Clare P. Grey, <b><i>Joule</i></b>, 2022, DOI: 10.1016/j.joule.2022.09.008