The stress and strain behavior of materials for energy storage and production

platinum catalyst;oxygen reduction reaction (ORR);tin electrode;silicon anode;alloying electrode;Lithium-ion batteries

Cason, Michael

关键词: platinum catalyst;    oxygen reduction reaction (ORR);    tin electrode;    silicon anode;    alloying electrode;    Lithium-ion batteries;   

Others  :  https://www.ideals.illinois.edu/bitstream/handle/2142/78580/Cason_Michael1.pdf?sequence=1&isAllowed=y

美国|英语

来源: The Illinois Digital Environment for Access to Learning and Scholarship

【 摘 要 】

The complex structural dynamics of materials systems involved in the production and storage of energy are examined in order to provide insight into the understanding and design of more effective systems. Within this dissertation, two categories of electrochemical systems are explored in the context of how their structural attributes relate to their function: high-capacity lithium-ion battery anode materials, specifically silicon and tin, and the surface stress changes of platinum, palladium, and rhodium catalysts for the oxygen reduction reaction of fuel cells. In the first section, silicon microstructuring is utilized in order to design structures that can withstand the large volumetric strains associated with forming lithium rich alloys during the normal operation of lithium-ion batteries containing silicon active anodes. A unique microstructure design is used to direct lithium transport through the silicon in order to mitigate performance-limiting material failure during normal battery operation. Like silicon, tin suffers from a similar strain-related failure when operating as an alloying electrode in lithium-ion batteries. A tabletop surface stress measurement is performed to monitor the evolution of stress, in situ, as tin thin films are electrochemically lithiated. Tin films with varying oxide content are evaluated and an evidence of an unexpected reversibility of tin oxide conversion products is discussed. In the subsequent sections, platinum, palladium, and rhodium catalysts are examined in-situ during the oxygen reduction reaction. In particular, platinum surface atom bond distance changes areiiiexamined via X-ray Absorption Spectroscopy (XAS), in particular Extended X-ray Absorption Fine Structure (EXAFS), and also with same tabletop surface stress measurement mentioned previously. The tabletop method shows loose quantitative agreement with the EXAFS measurement, suggesting that the method is capable of sensitivities necessary for observing structural dynamics relevant to surface-localized catalytic activity. Further work involving other catalysts, including palladium and rhodium, is therefore enabled and preliminary data is included and described in the appendix. Additionally, a critical review of the structural dynamics of supported nanoparticles is also included as an appendix.