High-Capacity and Long-Life Aqueous Zn-SPAN Batteries with Tandem Catalysis

Aqueous zinc-sulfur batteries are a high-capacity and cost-effective energy storage technology. However, the performance is plagued by the dissolution of intermediate polysulfides formed during conversion. Here, this issue is addressed by developing aqueous rechargeable Zn-sulfurized polyacrylonitrile (SPAN) batteries using tandem catalytic systems, containing water and tetraglyme (G4) with iodine (I₂) additives. Mechanistic study and experiments reveal that the fully conjugated molecular configurations circumvent the formation of soluble polysulfides and enable reversible co-storage of H⁺/Zn²⁺ with multiple redox-active centers. The reduced I₂ by G4 activates I^-/I₃ ^- redox couple in SPAN, reducing activation energy, and accelerating Zn-ion transfer kinetics. Additionally, it stabilizes the Zn anode by forming an organic-inorganic interphase that induces the generation of the predominant (002) plane. The as-assembled Zn-SPAN batteries exhibit excellent performances, with a high capacity of 1260.4 mAh g^-1 at 0.2 A g^-1, a high-rate performance (409.3 mAh g^-1 at 5 A g^-1), and a long cycling stability (81.8% capacity remained over 800 cycles at 2 A g^-1). This work takes a crucial step forward in organosulfur compounds accompanied by multi-electron transfer for the high-performance aqueous zinc-ion batteries.