The creation of new environmentally friendly and portable energy sources requires the development of technology used to produce lithium-ion batteries, especially their anodes. The aim of this study was to show the possibilities of the state-of-the-art ab initio approach for modeling battery anode materials. A quantum-mechanical study of the limiting filling of a silicene/aluminum anode with lithium has been performed. In this case, the changes in the structure, energy, and electronic properties of silicene that occur upon filling the anode have been studied. Lithium atoms are deposited both inside and on top of the channel formed by two parallel silicene sheets. The ratio of lithium to silicon varies in the range of 0.1–1.5. The gap in the silicene channel increases as the channel is filled with lithium. The filling of the silicene channel with lithium is associated with an increase in the Si–Si bond length in both silicene sheets without destruction of the channel. The infiltration of lithium into the space between the aluminum substrate and silicene sheet has been determined. Our calculation of the band structure has shown that, regardless of filling with lithium, the silicene-aluminum system exhibits metallic conductivity. The storage capacity of the combined anode (729 mAh g−1) significantly exceeds the capacity of graphite anodes. It was found that the top sheet of silicene acquires a negative electric charge upon significant lithium filling of the anode, exceeding the absolute value of the negative charge of the bottom sheet in contact with the aluminum substrate. Therefore, our model study has elucidated that the new silicene-aluminum anode is a promising material for the creation of a new generation of lithium-ion batteries. © 2023 Elsevier Ltd.