Double-Layer Honeycomb AIP: A Promising Anode Material for Li-, Na-, and K-Ion Batteries

The development of alkali metal-ion batteries requires anode materials with high capacity and fast kinetics. The present study theoretically investigates the double-layer honeycomb (DLHC) AlP as a potential anode material for alkali metalion batteries. It is found that the threefold hollow site is energetically favored for storing alkali metal atoms. DLHC AlP exhibits metallic properties after alkali metal adsorption. The calculated diffusion barriers for Li, Na, and K atoms on DLHC AlP are 0.38, 0.26, and 0.15 eV, respectively, which are comparable to those of other common two-dimensional materials. As an anode material, DLHC AlP has excellent multilayered adsorption ability for Li, Na, and K atoms. Therefore, it can deliver high specific capacities of 924, 1386, and 693 mA h g(-1), corresponding to Li2AlP, Na3AlP, and K1.5AlP. In addition, the highest plateaus of open circuit voltages are 0.56 V vs Li+/Li, 0.45 V vs Na+/Na, and 0.71 V vs K+/K, which are beneficial for achieving the high discharge voltage in full cells. The current work is expected to provide new knowledge for developing novel nanostructured materials for improving the performance of energy storage devices.