A computational study on the BN and AlN nanocones as anode materials for K-ion batteries

Abstract

The potential application of BN nanocone (BNNC) and AlN nanocone (AlNNC) as the anode material for the potassium-ion batteries (PIBs) was explored by means of the density functional theory calculations. The K cation adsorbed over the center of the apex ring of BNNC and AlNNC with the adsorption energies of −24.1 and −38.0 kcal/mol, respectively. While the K atom was physically adsorbed with a small adsorption energy. The maximum energy barrier which should be passed by the K cation to migrate over the surface of BNNC and AlNNC is 7.2 and 5.7 kcal/mol, respectively. These values are very small which yield a high ion mobility and quick charge/discharge rate. The minimum diffusion coefficient for K cation on the BNNC or AlNNC is computed to be 9.72 × 10−8 or 2.89 × 10−6 cm2/s. The cell voltage belonging to BNNC or AlNNC are nearly 0.90 or 1.47 V. We concluded that the AlNNC is a more promising anode material for PIB compared to the BNNC because of its higher voltage, ion mobility, and diffusion coefficient. By using diethyl ether as a solvent, the cell voltage is decreased by about 0.03 and 0.15 V in the case of BNNC and AlNNC, respectively.