A Universal Strategy Toward Low‐Cost Aqueous Sulfur–Iodine Batteries

Abstract

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.

Chaotropic Electrolyte Enabling Wide-Temperature Metal-Free Battery

“…Ag/AgCl) corresponding to the I + /I 0 redox couple (Figure a), which can also be confirmed by the voltage profile of the I 2 @CC cathode (Figure S21). The capacity asymmetry of the initial CV curve is attributed to the capacity loss in the initial cycle resulting from the dissolution of partial I + ions into aqueous electrolytes. Except for the initial cycle, the subsequent cycles overlapped, implying that the redox reactions are highly reversible in the presence of Cl – and OTf – anions.…”

“…Replacing an intercalation-type cathode with a nontoxic, low-cost, and low water solubility iodine (I 2 ) cathode not only enhances electrochemical reversibility due to the I + /I 0 conversion chemistry but also provides high redox potential (∼1 V vs . the standard hydrogen electrode (SHE)). , As for the anode, aromatic 3,4,9,10-perylenetetracarboxylic dianhydride (PTCDA) featuring an anhydride group and a highly crystalline structure shows an appropriate working potential and can accommodate NH 4 + through the donor–acceptor principle . The as-designed metal-free aqueous ammonium–iodine batteries (AIBs) are expected to provide advantages of low cost, high safety, nontoxicity, and superior electrochemical performance (e.g., long-term lifespan).…”

Hetero‐Polyionic Hydrogels Enable Dendrites‐Free Aqueous Zn‐I2 Batteries with Fast Kinetics

“…Some iodine hosts such as 2D MXenes, doped porous carbon materials, Prussian blue analogues, starch, and single atom catalysts were employed to construct efficient physical confinement and chemical adsorption for iodine species. [9][10][11][12][13][14][15][16][17][18] For Zn metal anode protection, effective approaches reported so far include surface coating layers (e.g., oxides, polymers, and metals), [19][20][21][22][23][24] optimized electrolytes (e.g., eutectic solution, water-in-salt, and gel-based electrolyte), [25][26][27][28][29][30][31][32][33][34] and threedimensional Zn hosts. [35] Apart from the dendrites prohibition, coating layers and separators could block the polyiodides shuttling via electrostatic repulsion effect or size limitation.…”

Synergistic Ion Sieve and Solvation Regulation by Recyclable Clay-Based Electrolyte Membrane for Stable Zn-Iodine Battery

“…5−7 Comparably, aqueous batteries, e.g., zinc−iodine batteries, are believed to be an ideal alternative due to the elemental abundance, high theoretical capacity, simple manufacturing process, and stable potential plateau of both zinc (Zn) metal anode and iodine cathode. [8][9][10]46 However, the state-of-the-art Zn-iodine batteries exhibit low Coulombic efficiency and rapid capacity decay and are therefore still far away from satisfactory for practical applications. The main obstacles are attributable to (i) the unstable Zn anode involving nonuniform electric fieldinduced dendrite growth, irreversible capacity decay, and even short circuit; 11,12 (ii) the generation of dissoluble polyiodides intermediates (e.g., I 3 − , I 5 − ) that lead to shuttle effects across the separator (cathode loss) and the further corrosion of Zn anode.…”

“…Large-scale energy storage based on secondary batteries is indispensable for the collection of electricity intermittently generated from renewable resources, such as sun, wind, and tide, to reduce environmental pollution and greenhouse gas emission. − To date, although commercial lithium ion batteries (LIBs) have been widely used as rechargeable devices for large-scale energy storage owing to their high energy density, safety issues regarding the flammable organic electrolyte and price concerns derived from the scarce resources of Li-salt severely restrict their sustainable utilization. − Comparably, aqueous batteries, e.g., zinc–iodine batteries, are believed to be an ideal alternative due to the elemental abundance, high theoretical capacity, simple manufacturing process, and stable potential plateau of both zinc (Zn) metal anode and iodine cathode. − , However, the state-of-the-art Zn-iodine batteries exhibit low Coulombic efficiency and rapid capacity decay and are therefore still far away from satisfactory for practical applications. The main obstacles are attributable to (i) the unstable Zn anode involving nonuniform electric field-induced dendrite growth, irreversible capacity decay, and even short circuit; , (ii) the generation of dissoluble polyiodides intermediates (e.g., I 3 – , I 5 – ) that lead to shuttle effects across the separator (cathode loss) and the further corrosion of Zn anode. , …”