Abstract
We report the in-plane electron transport in the MXenes (i.e., within the MXene layers) as a function of composition using the density-functional tight-binding method, in conjunction with the non-equilibrium Green’s functions technique. Our study reveals that all MXene compositions have a linear relationship between current and voltage at lower potentials, indicating their metallic character. However, the magnitude of the current at a given voltage (conductivity) has different trends among different compositions. For example, MXenes without any surface terminations (Ti3C2) exhibit higher conductivity compared to MXenes with surface functionalization. Among the MXenes with -O and -OH termination, those with -O surface termination have lower conductivity than the ones with -OH surface terminations. Interestingly, conductivity changes with the ratio of -O and -OH on the MXene surface. Our calculated I-V curves and their conductivities correlate well with transmission functions and the electronic density of states around the Fermi level. The surface composition-dependent conductivity of the MXenes provides a path to tune the in-plane conductivity for enhanced pseudocapacitive performance.
| Original language | English |
|---|---|
| Article number | 194701 |
| Journal | Journal of Chemical Physics |
| Volume | 158 |
| Issue number | 19 |
| DOIs | |
| State | Published - May 21 2023 |
Funding
This manuscript has been authored by UT-Battelle, LLC, under Contract No. DE-AC05-00OR22725 with the U.S. Department of Energy. The United States Government retains and the publisher, by accepting the article for publication, acknowledges that the United States Government retains a non-exclusive, paid-up, irrevocable, worldwide license to publish or reproduce the published form of this manuscript, or allow others to do so, for United States Government purposes. The Department of Energy will provide public access to these results of federally sponsored research, in accordance with the DOE Public Access Plan ( http://energy.gov/downloads/doe-public-access-plan ). We would like to thank Dr. Alessandro Pecchia of CNR-ISMN for the valuable discussions and help with scripts for the NEGF calculations. We would also like to thank Professor Yury Gogotsi and Dr. Paul Kent for the valuable suggestions regarding the design of our study. This material is based on the work supported by the Fluid Interface Reactions, Structures and Transport (FIRST) Center, an Energy Frontier Research Center funded by the U.S. DOE Office of Science. The research used the resources of the National Energy Research Scientific Computing Center (NERSC), a U.S. Department of Energy Office of Science user facility, operated under Contract No. DE-AC02-05CH11231. We would like to thank Dr. Alessandro Pecchia of CNR-ISMN for the valuable discussions and help with scripts for the NEGF calculations. We would also like to thank Professor Yury Gogotsi and Dr. Paul Kent for the valuable suggestions regarding the design of our study. This material is based on the work supported by the Fluid Interface Reactions, Structures and Transport (FIRST) Center, an Energy Frontier Research Center funded by the U.S. DOE Office of Science. The research used the resources of the National Energy Research Scientific Computing Center (NERSC), a U.S. Department of Energy Office of Science user facility, operated under Contract No. DE-AC02-05CH11231.
| Funders | Funder number |
|---|---|
| CNR-ISMN | |
| U.S. Department of Energy | |
| Office of Science | DE-AC02-05CH11231 |