SEMINAR: INVESTIGATION OF THE MORPHOLOGY EVOLUTION OF NANOSCALE CU2SB ELECTRODES DURING ELECTROCHEMICAL CYCLING VIA EX-SITU ELECTRON MICROSCOPY

摘要

Alloying active materials for lithium-ion batteries have been studied for many years as candidates for high energy density anodes. Binary elemental compositions are often used to combat disadvantages such as morphological instability, poor conductivity, and high volume expansion. One challenge of using such materials is determining definitively the location of each elemental component during charge and discharge. In the system Cu2Sb, the fast mobility of copper allows the formation, and subsequent reformation, of multiple Li_xCu_ySb phases and Cu2Sb. These transformations, considered critical to the increased reversibility of this system versus other transition row antimony intermetallics (e.g. FeSb2 and Mn2Sb), must depend on the state and location of copper as it is reversibly extruded and reincorporated. A definite mechanism requires this information to understand the underlying pathways for unwanted side reactions that result in capacity loss and lithium trapping.