Li-metal anodes can provide a significant improvement in energy storage capacity, though degradation of the Li-metal electrode during cycling in volatile liquid electrolytes prevents stability and longevity. Hear from Dr. Katherine Jungjohann about how her team has used cryogenic electron microscopy to understand these degradation mechanisms by imaging electrodes extracted from coin cells with FIB/SEM, and intact coin cells using a laser plasma FIB by Thermo Fisher Scientific.

Attend this webinar to learn about:

The advantages of cryo-EM for imaging solid-liquid interfaces
The advantage of imaging battery electrodes with a cryo stage on a laser plasma focused ion beam
Opportunities for nano-to-millimeter scale characterization of energy materials and systems

An interfacial understanding is necessary for developing strategies to commercialize high-energy density rechargeable lithium metal anode batteries, as currently, the lithium anode/electrolyte interface is unstable with prolonged cycling. We have used several strategies to improve the cycling performance of lithium metal anodes, including reducing the parasitic reactions between lithium metal and the electrolyte, and improving the electrodeposited lithium metal morphology. These strategies have generated unconclusive electrochemical data, that has required the need for nanoscale interfacial characterization of the solid-liquid electrode interfaces. Our team has used the cryogenic transfer workflow developed by Leica in collaboration with cryo-SEM/FIB tools by Thermo Fisher Scientific to cross-section lithium metal anodes and intact coin cell batteries to observe the interfacial structures, lithium morphology, and failure mechanisms relative to changes in electrode contract pressure and electrolyte chemistry. Cross-sectional SEM images and EDS maps of the lithium metal anodes have provided a better understanding of the electrodeposited lithium morphology, quantity of ‘dead’ lithium metal, and quantity of solid electrolyte interphase material that has formed alongside the lithium metal. In understanding lithium metal battery failure at the system level, we used a cryogenic stage in a laser plasma FIB to cross-section through the coin cell’s cap for imaging/mapping the entire battery stack under cryogenic conditions. We found that Li metal plating within the Celgard 2325 and Celgard 2400 separators was common across electrolyte chemistries at high rates > 1.5 mA/cm2 after 100 Li plating and stripping cycles for Li-metal half cells. The tools, methods, and results of these studies will be detailed in this presentation.