Lithium (Li) metal is regarded as one of the most promising anode candidates for future high energy density lithium batteries. The practical application of Li-metal anodes, however, is hindered by the uncontrollable growth of dendrites resulting from both huge volume change and unstable solid-electrolyte interfaces upon cycling. Herein, we propose a novel “house strategy” that utilizes the 3D NiO nanosheets decorated nickel foam as the frame to confine Li metal and the inorganic [LiNBH]n chains with high Li ion conductivity as the artificial protective proof to establish a stable dendrite-free Li metal anode. Benefiting from the synergistic effect of the 3D NiO/Ni foam in lowering the local current density and accommodating the huge volume change of Li metal and the [LiNBH]n protective layer in facilitating uniform Li+ diffusion and regulating Li deposition beneath this layer, the LiNBH-Li@Ni electrode presents an excellent long-term cycling lifespan of over 800 h at both 1 and 3 mA cm−2 with a high areal capacity of 5 mAh cm−2 in symmetric cells. Upon coupling this anode with LiFePO4 cathode, the thus-assembled full cells deliver an ultrahigh reversible capacity of 127.4 mAh g−1 at 1 C after 200 cycles.