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 inconclusive electrochemical data, which 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 Thermo Scientific cryo-SEM/FIB tools 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.

Watch this webinar to learn more about:

• Advantages of cryo-EM for imaging solid-liquid interfaces
• 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