Bidirectional Soft Catalysts for Improved Power Performance of Li‐S Batteries

Lithium‐sulfur (Li‐S) batteries are attractive for next‐generation energy storage owing to their high theoretical energy density and low cost, yet their practical performance is limited by sluggish redox kinetics. Here, we introduce a soft catalyst in which a polymer‐metal complex is directly integrated into the binder, creating a catalytically active microenvironment that enables efficient and bidirectional sulfur catalysis. A polyvinyl alcohol (PVA) scaffold stabilizes metal ions through chelation with the electron‐donating ‐OH groups of PVA, forming homogeneously distributed catalytic domains in the sulfur cathode. Among the systems investigated, PVA‐Cu exhibits the highest catalytic activity, arising from optimal sulfur binding energies, Cu‐S d‐p hybridization, and additional electronic states near the Fermi level. As a result, the PVA‐Cu cells deliver high capacities at 3 mg cm −2 of 1,100 mAh g −1 at 1 C with 82% capacity retention over 300 cycles, while at higher loadings of 9 mg cm −2 , the cells deliver 813 mAh g −1 (7.3 mAh cm −2 ) at 0.5 C. In a pouch cell prototype, stable cycling at 0.5 C delivers a discharge capacity of 790 mAh g −1 and a power density of 150 W kg −1 , which lies within the upper range of reported Li‐S pouch‐cell performance in terms of operating rate and power density.