Penta-PBN Monolayer as a Well-Balanced Anode Material for Alkali Metal-Ion Batteries

The development of lithium-ion batteries is a hot topic today, while sodium-ion and potassium-ion batteries are also attracting much attention due to their larger reserves compared to the increasingly scarce Li. Using first-principles calculations based on density functional theory, we investigated the performance of penta-phosphorus boron nitride (PBN) as an anode material for alkali metal-ion batteries. The low diffusion barrier of penta-PBN (0.35/0.32/0.356 eV for Li/Na/K) symbolizes excellent charge/discharge rates. Additionally, penta-PBN exhibits the same maximum theoretical capacity of 480.38 mA·h·g^–1 for Li, Na, and K. The average open-circuit voltage of penta-PBN (0.85/0.76/0.93 V for Li/Na/K) is also within the required threshold range of 0.1–1.0 V. Moreover, penta-PBN with metal atoms fully adsorbed shows a negative lattice expansion rate on the a-axis and b-axis. More importantly, penta-PBN possesses prime wetting properties for some common commercial electrolytes (organic solvents and metal salts). Therefore, penta-PBN has great potential for application in alkali metal-ion batteries.