Penetration of lithium metal and uncontrollable growth of lithium dendrites of lithium metal batteries (LMBs) easily induce safety concerns. Herein, we propose a smart lithium-manganite/graphene-oxide/lithium (LMO/GO/Li) battery with rationally designed trilayer films as separator, in which GO film is sandwiched by two pieces of commercial polymer microporous membranes. This unique LMO/GO/Li battery possesses the merits of anti-piercing and eliminating Li dendrites. Once being pierced, the middle GO layer can chemically etch metallic Li based on the spontaneous redox reaction and thus the LMO/GO/Li battery can work normally without short-circuit. Meanwhile, Li dendrites can be efficiently eliminated by GO to avoid internal shorting. Consequently, the LMO/GO/Li battery can reversibly charge/discharge for 6000 cycles that is ca. 48 times longer than that of conventional LMO/Li battery, and still retain a high Coulombic efficiency of 93%. This work not only conceptually provides new opportunities for developing other anti-piercing batteries, but also paves the way for building dendrite-free LMBs.