A computational study on the BN-yne sheet application in the Na-ion batteries

Although Li-ion batteries are extensively applied, short lifetime, high cost, and safety problems limit their application. Na-ion batteries (NIB) might be an alternative to the Li-ion owing to wide availability, low cost, and nontoxicity of Na. Here, we performed density functional theory calculations to investigate the possible application of a graphyne-like BN layer (BN-yne) in the anode of NIBs. The adsorption energies of Na and Na⁺ on the BN-yne are predicted to be -15.3 and -54.6 kcal/mol, respectively. It was found that the maximum barrier energy for migration of Na atom and Na⁺ ion through BN-yne surface is about 20.2 and 16.5 kcal/mol, respectively. The calculated cell voltage for the BN-yne are predicted to be and 1.70 V. Using an electric field of -0.02 a. u. much more strengthens the interaction of Na⁺ with the BN-yne compared to the Na atom, increasing the cell voltage of NIB to 2.10 eV. We showed that a high Na storage capacity (Na₄B₂N₂), high cell voltage and diffusion ability of BN-yne make it a promising candidate for the NIB anode material.