The design and manufacture of advanced materials based on biomaterials provide new opportunities to solve many technological challenges. In this work, a highly graphitized wood framework (GWF) with a porous tunnel structure and microvilli is constructed as a multifunctional interlayer to improve the electrochemical performance of lithium–sulfur (Li–S) batteries. The GWF not only retains the 3D transport network of wood, but also offers increased deposition sites for polysulfides through the microvilli which grow on the inner surfaces of the carbon tunnels. Electrochemical tests show that GWF effectively enhances the initial discharge capacity of the Li–S battery to 1593 mAh g−1 at 0.05 C, with a low capacity decline of 0.06% per cycle at 1 C. Besides, the GWF interlayer also effectively protects lithium anodes from corrosion by Sx2−, thus they still keep their metallic luster and clean surface even after long charge-discharge cycles. These enhancements are attributed to the high conductivity, abundant microvilli, and tunnel confinement effects of GWF, which effectively inhibit the shuttle effect of polysulfides by the same principle as nose hairs filtering the air. This work presents a new understanding of bionic/biomaterials and a new strategy to improve the performance of Li–S batteries.