Hexagonal Ti₂B₂ monolayer: a promising anode material offering high rate capability for Li-ion and Na-ion batteries

Abstract

Combining the first-principles density functional method and crystal structure prediction techniques, we report a series of hexagonal two-dimensional transition metal borides including Sc2B2, Ti2B2, V2B2, Cr2B2, Y2B2, Zr2B2, and Mo2B2. Their dynamic and thermal stabilities are testified by phonon and molecular dynamics simulations. We investigate the potential of the two-dimensional Ti2B2 monolayer as an anode material for Li-ion and Na-ion batteries. The Ti2B2 monolayer possesses high theoretical specific capacities of 456 and 342 mA h g-1 for Li and Na, respectively. The very high Li/Na diffusivity with an ultralow energy barrier of 0.017/0.008 eV indicates an excellent charge-discharge capability. In addition, good electronic conductivity during the whole lithiation process is found by electronic structure calculations. The very small change in volume after the adsorption of one, two, and three layers of Li and Na ions indicates that the Ti2B2 monolayer is robust. These results highlight the suitability of Ti2B2 monolayer as well as the other two-dimensional transition metal borides as excellent anode materials for both Li-ion and Na-ion batteries.

Mo2B, an MBene member with high electrical and thermal conductivities, and satisfactory performances in lithium ion batteries

“…MBene, by replacing the X element of MXene with the neighboring B, naturally aroused increasing attention in the recent three years. [29][30][31][32][33] Moreover, most boron-containing compounds are high-temperature refractory materials. 34,35 With respect to the formula M n+1 X n T x for MXenes, MBenes have more adjustable space.…”

“…Ti 2 B 2 was determined to be a candidate anode material for LIBs and SIBs. 29 30 Although H-type Mo 2 B has been predicted, 30 this structure was not discussed in detail. In their experiment, Alameda et al used MoAlB as the precursor to synthesize MBene, but they obtained MoAlB slabs of nanoscale thickness in their rst attempt.…”

Doping‐Driven Antiferromagnetic to Ferromagnetic Phase Transition in Tetragonal Cr2B2 Monolayer

“…In general, the estimated lattice constants of both, tetra-CrMnB 2 (2.79 Å) and tetra-CrVB 2 (2.89 Å) sheets are within the range of values for the Cr 2 B 2 (2.88 Å) and TiC (2.99 Å) sheets, respectively. [13,14] Figure 1b shows the electron localization functions (ELF). In both cases, the localization of the charge is located around B atoms, which clearly indicates an ionic bonding character.…”

“…2D MBene X 2 B 2 ðX ¼ Ti, Mo, ZrÞ have been reported to hold a promise toward the Li-and Na batteries application. [13][14][15] As for magnetism, the MnB sheet is theoretically found to exhibit FM at room temperature with a considerable MAE. [16] In addition to the MBene sheet of a particular single transition metal (TM) atom, combinations of two different TM atoms in the unit cell are important in the field of magnetism.…”

“…2D MBene have been reported to hold a promise toward the Li‐ and Na batteries application. [ 13–15 ] As for magnetism, the MnB sheet is theoretically found to exhibit FM at room temperature with a considerable MAE. [ 16 ]…”