Abstract
We employed time-resolved, in situ neutron reflectometry to observe a dynamic electrode-electrolyte interface under conditions relevant to Li-mediated electrochemical N2reduction reaction (NRR). This method leverages the sensitivity of neutrons to Li and fast time resolution (∼1 min) to observe the formation of a layer containing Li species at the electrode surface within minutes of applying a current density (-0.1 mA/cm2). Notably, within the first 6 min, we did not observe a solid-electrolyte interphase (SEI) distinct from this layer, providing insight into recent reports demonstrating performance advantages of short current cycles interspersed with open-circuit conditions for NRR. At longer time scales following chronopotentiometry (∼2 h), a multilayer SEI remained, though the presence of Li was not evident, indicating that the layers containing Li species observed over shorter time scales degrade almost entirely under open-circuit conditions, leaving SEI layers consisting of electrolyte decomposition products. We thus present the first application of neutron reflectometry toward the NRR-through fast time-resolved measurements, we have enabled a path toward understanding the electrochemical NRR as well as dynamic systems across a wide range of energy technologies.
| Original language | English |
|---|---|
| Pages (from-to) | 1939-1946 |
| Number of pages | 8 |
| Journal | ACS Energy Letters |
| Volume | 7 |
| Issue number | 6 |
| DOIs | |
| State | Published - Jun 10 2022 |
Funding
S.J.B. and M.D. contributed equally to this work. This work was supported by the Villum Foundation V-SUSTAIN Grant 9455 to the Villum Center for the Science of Sustainable Fuels and Chemicals. Preliminary testing of in situ methods and sample preparation was supported by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, Chemical Sciences, Geosciences, and Biosciences Division, Catalysis Science Program through the SUNCAT Center for Interface Science and Catalysis. A portion of this research used resources at the SNS, a Department of Energy (DOE) Office of Science User Facility operated by ORNL. Neutron reflectometry measurements were carried out on the Liquids Reflectometer at the SNS, which is sponsored by the Scientific User Facilities Division, Office of Basic Energy Sciences, DOE. ORNL is managed by UT-Battelle LLC for DOE under Contract DE-AC05-00OR22725. XPS characterization of the cathode was performed at the Stanford Nano Shared Facilities (SNSF), supported by the National Science Foundation under award ECCS-2026822. This material is based upon work supported by the National Science Foundation Graduate Research Fellowship under Grant No. DGE-1656518. Any opinions, findings, and conclusions or recommendations expressed in this material are those of the authors and do not necessarily reflect the views of the National Science Foundation.
