Abstract:
Two-dimensional transition metal borides (MBenes) have demonstrated outstanding electrochemical properties, making them highly promising candidates for energy storage applications. To enhance the anode performance of rechargeable zinc-ion batteries (ZIBs), this study employs first-principles calculations to systematically investigate the application potential of orthorhombic (o-M
2B
2) and hexagonal (h-M
2B
2) phases of Mo
2B
2, Cr
2B
2, and Ti
2B
2. The results reveal that both o-M
2B
2 and h-M
2B
2 structures are thermodynamically stable and possess good electrical conductivity. For the same transition metal (M), o-M
2B
2 and h-M
2B
2 exhibit identical maximum zinc intercalation concentrations, corresponding to theoretical capacities of 502.03 mA·h·g
−1 for Mo
2B
2, 853.40 mA·h·g
−1 for Cr
2B
2, and 913.46 mA·h·g
−1 for Ti
2B
2. Notably, Cr
2B
2 and Ti
2B
2 offer significantly higher theoretical capacities compared to conventional zinc anodes. In addition, Zn atoms exhibit very low diffusion barriers on h-Mo
2B
2 (84 meV), h-Cr
2B
2 (82 meV), h-Ti
2B
2 (76 meV), and o-Ti
2B
2 (206 meV), indicating excellent ion transport properties. These findings suggest that two-dimensional M
2B
2 (M = Mo, Cr, Ti) materials are highly promising anode candidates for ZIBs.