Abstract
MXenes (two-dimensional transition-metal carbides and nitrides) are promising materials for capacitive energy storage due to the large chemical space of existing and potential compositions, but only a few of them have been experimentally explored. In this work, we computationally screen a series of MXene electrodes (M n+1 X n T x : M = Sc, Ti, V, Zr, Nb, Mo; X = C, N; T = O, OH; n = 1-3) to simulate their pseudocapacitive performance in the aqueous H 2 SO 4 electrolyte. We find that nitride MXenes exhibit better pseudocapacitive performance than carbide MXenes. Especially, Ti 2 NT x is predicted to have a high gravimetric capacitance over a wide voltage window, whereas Zr n+1 N n T x MXenes are predicted to possess the best areal capacitive performance. Evaluating the descriptors for the capacitance trends, we find that more positive hydrogen adsorption free energy (weak binding to H) and smaller change of the potential at the point of zero charge after H binding lead to higher capacitance. Our work provides helpful guidance to selectively develop high-performance MXene pseudocapacitors and to further screen MXene electrodes.
| Original language | English |
|---|---|
| Pages (from-to) | 315-321 |
| Number of pages | 7 |
| Journal | Journal of Physical Chemistry C |
| Volume | 123 |
| Issue number | 1 |
| DOIs | |
| State | Published - Oct 1 2019 |
Funding
This research is sponsored by the Fluid Interface Reactions, Structures, and Transport (FIRST) Center, an Energy Frontier Research Center funded by the U.S. Department of Energy (DOE), Office of Science, Office of Basic Energy Sciences. This research used resources of the National Energy Research Scientific Computing Center, a DOE Office of Science User Facility supported by the Office of Science of the U.S. Department of Energy, under Contract No. DE-AC02-05CH11231.