Defect engineering and metal decoration onto 2-D materials have gained major attention as a means of creating viable hydrogen storage materials. This Density Functional Theory (DFT) based study presents lithium decorated single vacancy (SV) and Stone-Wales (SW) defective silicene as a viable media for storing hydrogen via physisorption. Introducing defects increases the Li adatom’s binding energy from -2.36 eV in pristine silicene to -3.44 eV and -2.73 eV in SV and SW silicene, respectively, thus preventing Li adatom clustering. The presence of defects and Li adatom further aid hydrogen adsorption onto the substrates with binding energies present in the US-DOE set range of -0.2 to -0.7 eV/H ₂ with the highest binding energy measured to be -0.389 eV/H ₂. It was seen that both the Li-decorated defective systems were able to effectively store multiple H ₂ molecules up to 28 H ₂ with the highest gravimetric density being 5.97 wt %. The projected density of state plots indicates a combined overlap of the Li (p) and Li (s) orbitals with the H (s) orbital leading to enhanced H ₂ binding energies. Molecular dynamic simulations conducted at 300 K confirm the stability of the Li adatom as well as the adsorbed H ₂ molecules at room temperature, establishing the viability of these systems as effective, high gravimetric density, physisorption-based hydrogen storage media.