For developing new generation nanomaterials for energy applications, the understanding of the factor/mechanism governing their performance is of primary importance. Advanced (scanning) transmission electron microscopy ((S)TEM) techniques have recently been developped to investigate the relationship between the nanomaterials' structure and their functions, with the help of combined electrochemical and theoretical approaches. In this talk, I will discuss how to use advanced TEM techniques to characterize the redox reaction of the transition metal oxide nanoparticles for lithium ion batteries. While ex situ TEM study reveals the structural change in the real cell and probe local phase, interfacial and chemical information at an atomic resolution, in situ TEM study can help us to understand the phase evolution in real time. In the case of spinel oxides nanoparticles, Fe3O4 and Co3O4, we have observed the competition between intercalation and conversion reactions in non-equilibrium state. Surprisingly, these two reactions can be co-existed within one single particle. Phase-field simulation reveals that the reaction pathway is be governed by the rate of lithium diffusion. This talk highlights the unique capability of combining in situ TEM with theoretical simulation to investigate the mechanisms of redox reaction.

Probing phase evolution of metal oxide nanomaterials in batteries

256th National Meeting (2018)

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.