Real Time Optical Probes of Phase Transitions in Nanoscale Materials – Dr Akshay Rao, Cavendish Laboratory, Physics, Cambridge

October 15, 2021 @ 2:00 pm – 3:00 pm
Hilde Hambro

Reversible and irreversible phase transitions are key to the operation and eventual degradation of many nanoscale materials and devices. Operando imaging of such phase transitions at the nanoscale currently requires sophisticated synchrotron X-ray or electron microscopy techniques, which do not lend themselves to high-throughput material screening. In this talk I will introduce our recent work to develop simple lab-based optical scattering microscopies to track phase transitions under operating conditions. For instance, in the archetypal Li-ion battery cathode material LixCoO2, we visualize the insulator-to-metal, solid solution and lithium ordering phase transitions directly and determine rates of lithium diffusion at the single-particle level, identifying different mechanisms on charge and discharge. We are also able to capture the dynamic formation of domain boundaries between different crystal orientations associated with the monoclinic lattice distortion at the Li0.5CoO2 composition [1]. I will discuss how such methods might be applied to other systems such memristors and bio-electronic circuits.

[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, Nature, 594, 522–528, (2021).

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