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.