Computational evaluation of ScB and TiB MBenes as promising anode materials for high-performance metal-ion batteries

Emerging as a new family of two-dimensional materials, transition-metal borides, namely MBenes, are expected to possess outstanding physical and chemical properties owing to their layered structures analogous to MXenes. Here, we explore the electrochemical properties of ScB and TiB monolayers as anode materials for lithium- and sodium-ion batteries by density-functional theory calculations. Our results reveal that Li/Na ions can be stably adsorbed on surfaces of both monolayers with moderate adsorption energy, rapid charge/discharge rate, higher storage capacity, and much lower diffusion energy barrier (0.108 eV for Li ion on ScB, 0.105 eV for Li ion on TiB, 0.072 eV for Na ion on ScB, and 0.063 eV for Na ion on TiB) as compared with other MBene monolayers currently reported. Meanwhile, the open-circuit voltages all fall in the range of 0--1 V for Li/Na ion on the monolayers, which may effectively suppress the formation of Li/Na dendrite on anodes during the charge/discharge process. Besides, at room temperature, Li adatoms could be adsorbed on the monolayers more stably than Na adatoms. Our work demonstrates that ScB and TiB monolayers should be promising two-dimensional anode materials for lithium-ion batteries and are less suitable for sodium-ion batteries. These results advance our understanding on the electrochemical performances of MBenes and provide important insights into the design and development of high-performance electrode materials for metal-ion batteries.