We computationally explore an alternative to stabilize one-dimensional (1D) silicon-lithium nanowires (NWs). The Li₁₂Si₉ Zintl phase exhibits the NW [Li6Si5]∞1, combined with Y-shaped Si₄ structures. Interestingly, this NW could be assembled from the stacking of the Li₆Si₅ aromatic cluster. The [Li6Si5]∞1@CNT nanocomposite has been investigated with density functional theory (DFT), including molecular dynamics simulations and electronic structure calculations. We found that van der Waals interaction between Li’s and CNT’s walls is relevant for stabilizing this hybrid nanocomposite. This work suggests that nanostructured confinement (within CNTs) may be an alternative to stabilize this free NW, cleaning its properties regarding Li₁₂Si₉ solid phase, i.e., metallic character, concerning the perturbation provided by their environment in the Li₁₂Si₇ compound.