- Katherine Steinberg Massachusetts Institute of Technology ,
- Xintong Yuan University of California, Los Angeles ,
- Nikifar Lazouski Massachusetts Institute of Technology ,
- Channing K. Klein California Institute of Technology ,
- Karthish Manthiram California Institute of Technology ,
- Yuzhang Li University of California, Los Angeles
Electrifying ammonia synthesis will be vital to the decarbonization of the chemical industry, as the Haber-Bosch process contributes significantly to global carbon emissions. A lithium-mediated pathway is among the most promising ambient-condition electrochemical ammonia synthesis methods. However, the role of metallic lithium and its passivation layer, the solid electrolyte interphase (SEI), remains unresolved. Here, we apply a multiscale approach that leverages the powerful cryogenic transmission electron microscopy (cryo-TEM) technique to reveal new insights that were previously inaccessible with conventional methods. We discover that the proton donor (e.g. ethanol) governs lithium reactivity toward nitrogen fixation. Without ethanol, the SEI passivates lithium metal, rendering it inactive for ammonia production. Ethanol disrupts this passivation layer, enabling continuous reactivity at the lithium surface. As a result, metallic lithium is consumed via reactions with nitrogen, proton donor, and other electrolyte components. This reactivity across the SEI is vital to device-level performance of lithium-mediated ammonia synthesis.
Supplementary Information - Imaging nitrogen fixation at lithium solid electrolyte interphases via cryo-electron microscopy