Two-dimensional transition metal carbides and carbonitrides, MXenes, are synthesized by etching atomically thin metal layers from MAX phases (ternary layered carbides/nitrides). The surface of the as-synthesized MXene has a mixture of moieties, including O, OH, and F, which adds versatility and complexity to this system. Being both electrically conductive and hydrophilic - a rare combination of properties, MXene is an excellent platform for investigating electrode/electrolyte interfaces for electrochemical energy storage with aqueous electrolytes. Investigating MXene synthesis by exploring surface termination and ion intercalation thus forms a fundamental first step to understanding the structure and property of MXene members. In particular, the ability to extract structural models from experimental data with the atomic-level detail needed to guide and validate leading nanoscale theories is a unifying challenge in the study of materials chemistry, impacting catalysis, biomineralization, drug delivery, fuel cell and battery chemistry, and geological processes, to name a few. In this presentation, the structure of pristine and cation intercalated Ti3C2- and Ti3CN-MXenes are investigated through the integration of density functional theory as well as molecular dynamics with a newly established force field. We describe and benchmark a novel way of modeling layered materials with real interfaces (diverse surface functional groups and stacking order between the adjacent monolayers) against diffraction data. The developed models are used to elucidate surface reactions and give insights on intercalation processes, as well as variety of physical, chemical and applied properties of MXene materials.

Theory, experiment and predictions: Transition metal carbides (MXenes) for electrochemical capacitors

255th National Meeting (2018)

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.