MXene Phase with C₃ Structure Unit: A Family of 2D Electrides

Abstract

A new structural phase is discovered for M2CO2 MXenes with M = Sc, Y, La, Lu, Tm, and Ho. The hexagonal carbon layer sandwiched between M atoms, typical for MXenes, is transformed into C3 trimers with anionic electrons localized in quasi zero‐dimensional lattice spaces in‐between the C3 units, so the systems can be described as [M6 C3 O6]+II : 2e− electrides. The systems are readily ionized into [M6 C3 O6]+II with very low ionization energy via an anti‐doping mechanism. It is shown that this new structure of Sc2CO2 can bind multiple lithium atoms, with low migration barriers. The findings indicate that these M2CO2 MXenes with unusual carbon trimers are a new family of 2D electride insulators with the potential for charge storage applications, thermal field emission, and as anode material in lithium batteries.

Demonstrating the Potential of Alkali Metal-Doped Cyclic C6O6Li6 Organometallics as Electrides and High-Performance NLO Materials

“…As the electrides contain a loosely bound electronic density, not belonging to any atom, the electronic stability is very important, which is directly related to the vertical ionization energies. , Both electrides, Li@C 6 O 6 Li 6 and Na@C 6 O 6 Li 6 , possess sufficiently high vertical ionization energies of 2.83 and 3.03 eV, respectively, which is indicative of their electronic stability.…”

Sc2C, a 2D Semiconducting Electride

“…This assignment appears to be correct and it is not known whether a layered Sc 2 C electride exists. Currently, a 2D Sc 2 C MXene structure has been explored computationally , and calculations predict that layered Sc 2 C would be an electride . In addition, 2D Sc 2 C has been predicted to store an impressive 8% hydrogen by weight , and reversibly store fluoride as a battery anode at capacities that exceed state-of-the-art lithium-ion batteries .…”

Parallel Alignment of Methylammonium Cations in an Orthorhombic CH3NH3PbCl3 Single Crystal Observed by Polarized Micro-Raman Scattering Spectroscopy

“…The phonon dispersion of the primitive rhombic structure was calculated with Phonopy with the force constants obtained with a minimal set of 2 × 2 × 2 supercells. The vibration frequencies of MAPbCl 3 structures were obtained using the VASP package, and their Raman tensors and Raman intensities were evaluated using the Raman off-resonance activity calculator. − More computational details can be found in our previous publications. − …”