Aqueous zinc-based batteries are promising candidates for the grid-scale energy storage owing to their nonflammability, ecofriendliness, and low cost. Nevertheless, their practical applications are hindered by the relatively low capacity and energy density. Herein, we develop a quasi-solid-state aqueous zinc–dual halogen battery composed of freestanding carbon cloth–iodine cathode and in situ prepared concentrated aqueous gel electrolyte. The freestanding composite cathode and aqueous gel electrolyte can afford iodine source and bromide ions, respectively, thus activating the I–/I0/I+ reaction by forming [IBr2]− interhalogen. Furthermore, the conversion reaction of Br–/Br0 in [IBr2]− interhalogen is stimulated due to the catalytic effect of iodine. Therefore, this rationally designed aqueous dual halogen conversion chemistry enables three successive redox reactions (i.e., I–/I0, I0/I+, and Br–/Br0). Additionally, the LiNO3 additive and acrylamide (AM)-based polymer matrix not only stabilizes the anode/electrolyte interface but also restrains the side reactions and dissolution/diffusion of active species. Consequently, the as-assembled aqueous zinc–dual halogen battery exhibits high areal capacity and energy density.

Rechargeableaqueous batteries with non-toxic and non-flammable features are promising candidates for large-scale energy storage. However, their practical applications are impeded by the insufficient electrochemical stability windows of aqueous electrolytes and intrinsic drawbacks of current electrodes. Herein, an aqueous sulfur-iodine chemistry that can be deployed in aqueous battery systems by employing water-in-bisalt (WiBS) electrolyte, sulfur composite anode, and iodine composite cathode is demonstrated. The freestanding iodine/carbon cloth cathode and halide-containing WiBS electrolyte can support the continuous I + /I 0 reaction by forming interhalogen. Meanwhile, the highly-concentrated electrolyte and inorganic-based solid electrolyte interphase can effectively suppress the dissolution/diffusion of polysulfides, thus realizing S/S x 2− conversion reactions on the anode. Therefore, the as-assembled aqueous sulfur-iodine batteries based on S/S x 2− and I + /I 0 redox couples can deliver a high energy density of 158.7 Wh kg −1 with a considerable cycling performance and safety. Furthermore, this chemistry can be further extended to multivalent ion-based battery systems. As demonstration models, Ca-based and Al-based aqueous sulfur-iodine batteries are also fabricated, which provide a new avenue towards the development of aqueous batteries for low-cost and highly safe energy storage.

No abstract

No abstract