Naval Research Lab,
Keywords: Si anode, MEMS, in situ testing, lithiation, Li-ion battery, high temperature
Summary:Nanostructured electrodes have shown great potential in the development of Li-ion batteries with higher energy and power densities and longer cycle life. A fundamental understanding of the mechano-electrochemical behavior during charging/discharging cycles is essential for optimal and reliable design. Previous work has utilized in situ experimental techniques in an electron microscope to directly visualize material response during the reaction cycles. Unfortunately, the present in situ test methods are limited to room temperature and, as a result, the effect of temperature on charging/discharging cycles is not well understood. These electrochemical processes are intrinsically temperature sensitive, particularly for nanostructured electrodes. Here we present a novel microdevice that allows high resolution in situ observation of mechano-electrochemical response of nanomaterials in a scanning electron microscope with controlled temperature. The microdevice consists of built-in microcircuits for concurrent heating and temperature measurement during in situ experiments. To demonstrate these unique capabilities, we present the design, microfabrication and thermal characterization of this new class of microdevice.