Ultra‐Low Dosage Lignin Binder for Practical Lithium–Sulfur Batteries

Abstract Polymeric binders stabilize lithium–sulfur (Li–S) batteries by suppressing the shuttle of lithium polysulfide (LiPS) and volume variation, but the dosage of state‐of‐the‐art binders in sulfur cathodes (≈20 wt%) hinders the electron/ion transfer and decreases the cell‐specific density. Here, a wood‐inspired lignin binder is developed after modification with amino acids for practical Li–S batteries at ultra‐low low dosage (2 wt%). Benefiting from strong and balanced adhesions with active/conductive/current collector materials, robust mechanical properties, and super LiPS anchoring capability, the Li–S cell delivers an initial discharge capacity of 864 mAh g −1 at 0.5 C and can readily operate 1000 cycles. Moreover, the pouch cell with high mass loading (4.75 mg cm −2 ) also delivers a high energy density of 484 Wh kg −1 . This work provides important guidance in binder design for the sulfur cathode and paves a new way for the practical application of Li–S batteries.