Probing pristine and defective NiB6 monolayer as promising anode materials for Li/Na/K ion batteries

Two-dimensional material NiB6 has attracted attention and predicted to be a potential candidate for next-generation nanoscale devices duo to its excellent mechanical and electronic properties. In this section, by using first-principles calculations, the pristine and defect-containing NiB6 substrates as a potential anode for alkali metal ion batteries are systematically studied. Our calculated results show that the pristine NiB6 monolayer might has promising application for alkali-ion batteries due to its large adsorption energy, high specific capacity (1301.61 mA.h.g(-1)), and fast migration capability (energy barrier is 0.43/0.23/0.14 eV for Li/Na/K). Meanwhile, pristine NiB6 monolayer can also provide an appropriate average open circuit voltage (0.96/0.71/0.69 V for Li/Na/K). Alkali metal atoms adsorption and diffusion mechanism on the selective defective NiB6 substrates show that defect sites tend to act as metal trapping sites, which improve the NiB6 monolayer adsorption ability of alkali metal atoms but hinder the metal atoms diffusion around the defects. The present study lays a foundation for ion battery applications of NiB6 monolayer and offers a better understanding of the defect effects on alkali metal atoms adsorption and diffusion properties on low-dimensional materials.