Two-dimensional (2D) materials are promising candidates for next-generation battery technologies owing to their high surface area, excellent electrical conductivity, and lower diffusion energy barriers. In this work, we use first-principles density functional theory to explore the potential for using a 2D honeycomb lattice of aluminum, referred to as aluminene, as an anode material for metal-ion batteries. The metallic monolayer shows strong adsorption for a range of metal atoms, i.e., Li, Na, K, and Ca. We observe surface diffusion barriers as low as 0.03 eV, which correlate with the size of the adatom. The relatively low average open-circuit voltages of 0.27 V for Li and 0.42 V for Na are beneficial to the overall voltage of the cell. The estimated theoretical specific capacity has been found to be 994 mA h/g for Li and 870 mA h/g for Na. Our research highlights the promise of aluminene sheets in the development of low-cost, high-capacity, and lightweight advanced rechargeable ion batteries.