ME Department Seminar: Ju Li (MIT)

11:00 am on Friday, November 8, 2013
RM 245, 110 Cummington Mall
Electrochemical-mechanical actions: in situ TEM experiments and modeling -- The creation of a nanoscale electrochemical and mechanical testing platform [Science 330 (2010) 1515; Nano Letters 11 (2011) 4535; ACS Nano 6 (2012) 9425; Nature Nano. 8 (2013) 277] inside a transmission electron microscope (TEM) is reported, consisting of electron-transparent single nanowire electrodes and a liquid electrolyte, and direct observations of the electrochemical lithiation and delithiation of the nanowires. SnO2, ZnO, Si, Ge, graphene and carbon nanotube anodes and LiFePO4 nanowire cathode have been tested. Lithium embrittlement is found to be a persistent issue. These in situ experiments complement our modeling efforts, and together they provide insight into how materials degrade in service due to combined electrochemical-mechanical actions.