Fast solid-solid redox kinetics of aqueous ZnS batteries realized by selenium-linked electron transfer bridge

Aqueous ZnS batteries offer a safe and sustainable solution for future energy storage. However, the low electron-transfer efficiency and poor affinity between the sulfur cathode and iodine catalyst resulted sluggish redox kinetics severely limit their application. Here, we design a selenium-doped hollow carbon sphere host (Se-HCS) to construct a CSeS electron bridge motif, thus achieving fast solid-solid redox kinetics in aqueous ZnS batteries. Specifically, the CSeS electron bridge effectively connects sulfur with the carbon framework, facilitating the overall electron transfer during sulfur conversion. Meanwhile, the polar CSeS bridge enhances the affinity to polar I₃^- catalyst, improving the catalytic efficiency. Consequently, the aqueous ZnS battery delivers a high reversible capacity (1652 mA h g^-1 at 0.1 A g^-1), a low voltage polarization (0.49 V at 0.1 A g^-1), and an outstanding rate capability (450 mAh g^-1 at 6 A g^-1 after 500 cycles). This work establishes a new paradigm for overcoming the kinetic limitations of conversion-type electrodes by constructing a dual-functional CSeS electronic bridge within selenium-doped hollow carbon spheres, which holds broad significance for the design of the host material for metal‑sulfur batteries.