First-principles computational study of two-dimensional BeB2 monolayer as a material for negative high-rate sodium ion batteries

Sodium-ion batteries are of interest due to their low cost and abundance of natural resources. However, the exploration of suitable anode materials is a major challenge in advancing the technology of sodium-ion batteries. Herein, a novel type of Dirac cone two-dimensional material (BeB2) was systematically investigated based on first-principles calculations for its potential performance in sodium-ion batteries. The results show that BeB2 has good stability and conductivity, and the theoretical capacity of sodium atoms for monolayer BeB2 is 874.9 mAh g-1. The diffusion barrier is 0.231 eV, and the average open-circuit voltage is as low as 0.08 V. Encouragingly, the lattice change is only 1.2 %, and at the same time, the adsorption of sodium atoms also significantly improves the conductivity of BeB2. The above results indicate that BeB2 is a promising candidate as an anode material for high rate sodium-ion batteries.