A DFT study on AlN nanotubes and nanosheets as anodes for Mg-ion batteries

[Display omitted] •The applications of AlN nanotubes and nanosheets in MIB were investigated by DFT.•The Ead for Mg atom decreases with the diameter of AlNNTs, that for Mg ion shows a contrary trend.•AlNNT (6, 6) shows a smaller Eb (0.054 eV), and behaves a bigger D (1.51×10−3 cm2/s). The potential applications of ((n, 0), n = 4–8) zigzag AlN nanotubes (zAlNNTs), ((n, n), n = 4–6) armchair AlN nanotubes (aAlNNTs) and AlN nanosheets in Mg-ion batteries (MIBs) have been investigated by density functional theory calculations. Through the calculations of the adsorption energy, diffusion energy, diffusion coefficient, and theoretical voltage, we find that with the increasing diameter of the AlN nanotube (AlNNT), the adsorption energy for Mg shows a decreasing trend, while the adsorption energy for Mg2+ shows a contrary trend. Eventually this will cause the voltage to rise with the increasing diameter of the AlNNT. In addition, the diffusion energy barrier tends to decrease and diffusion coefficient becomes larger as the diameter of the AlNNT increases. The smallest diffusion energy barrier is only 0.054 eV and the corresponding maximum diffusion coefficient is 1.51 × 10−3 cm2/s. Therefore, large-diameter AlNNTs are suitable candidates for the anode materials of MIBs.