A simulation on the graphyne and its inorganic BN-like nanosheets as anode materials for Ca-ion batteries
Abstract
Although the Li-ion batteries have some advantages, they have some disadvantages such as high cost, short life, and safety issues. Recently, Ca-ion batteries (CIB) have been suggested to replace Li-ion batteries due to calcium wide availability, multivalent character, and nontoxicity. Now, we evaluated the potential application of graphyne and its BN analogous (BN-yne) in the CIBs with the use of the B3LYP-gCP-D3 approach. The adsorption of Ca2+ and Ca on the graphyne is stronger and weaker than those on the BN-yne, respectively. The highest energy barrier for Ca2+ migration on the BN-yne (4.3 kcal/mol) is much lesser than that on the graphyne (5.9 kcal/mol) because of a strong cation-lone pair interaction in the BN-yne compared to the weak cation-π interaction of graphyne. Therefore, we realise the potential of the BN-yne in providing a greater Ca ion mobility and a more rapid charge/discharge rate compared to graphyne. Diffusion coefficient values calculated for the Ca2+ on the surface of graphyne and BN-yne are 3.27 × 10−11 and 5.14 × 10−9 cm2/s, and the predicted cell voltages are 3.38 and 3.66 eV, respectively. The results suggest that the BN-yne sheet may be a superior anode candidate for CIBs compared to the graphyne.