A Dual Plating Battery with the Iodine/[ZnI_x(OH₂)_4−x]^2−x Cathode

Abstract

Plating battery electrodes typically deliver higher specific capacity values than insertion or conversion electrodes because the ion charge carriers represent the sole electrode active mass, and a host electrode is unnecessary. However, reversible plating electrodes are rare for electronically insulating nonmetals. Now, a highly reversible iodine plating cathode is presented that operates on the redox couples of I2/[ZnIx(OH2)4−x]2−x in a water‐in‐salt electrolyte. The iodine plating cathode with the theoretical capacity of 211 mAh g−1 plates on carbon fiber paper as the current collector, delivering a large areal capacity of 4 mAh cm−2. Tunable femtosecond stimulated Raman spectroscopy coupled with DFT calculations elucidate a series of [ZnIx(OH2)4−x]2−x superhalide ions serving as iodide vehicles in the electrolyte, which eliminates most free iodide ions, thus preventing the consequent dissolution of the cathode‐plated iodine as triiodides.

Stacked Lamellar Matrix Enabling Regulated Deposition and Superior Thermo‐Kinetics for Advanced Aqueous Zn‐Ion System under Practical Conditions

“…) will limit the rate performance during charging/discharging to further reduce power density of the battery; the hydrogen evolution reaction competing with Zn deposition easily results in drastic volume changes of the system; [4][5][6][7] the water decomposition increases the content of OH − around Zn anode which leads to the generation of insoluble and inert by-products; and the inhomogeneous ion deposition would cause the dendrite growth, internal short-circuit, and even the destruction of anode structure. Various strategies have been proposed to alleviate these obstacles and enhance the reversibility of zinc metal anode in aqueous electrolytes, such as interface modification, [8][9][10][11][12][13][14][15] novel additives, [16][17][18] and electrolytes.…”

Dual‐Network Structured Hydrogel Electrolytes Engaged Solid‐State Rechargeable Zn‐Air/Iodide Hybrid Batteries

“…This result could be explained by iodide ions destroying the solvation structure of Zn ions and strengthening the O−H bond in H 2 O. Therefore, the reactivity of H 2 O decreases, and the HER is inhibited to some degree [12, 45–48] . Therefore, the introduction of KI in the solid‐state electrolyte results in the cathode oxygen reaction being replaced by iodide/iodate redox during discharge/charging in the rechargeable ZABs, which not only reduces the overpotential of the cathodic reaction but also enhances the interface stability of the anode, thus realizing a high‐performance renewable and rechargeable Zn‐air/iodide hybrid battery even in a sealed configuration.…”

Application‐Based Prospects for Dual‐Ion Batteries

“…Halogen conversion has also been investigated, primarily in iodine chemistries (I 2 , I 3 − , I − ), where dissolved anions in the electrolyte undergo redox reactions. However, these cell chemistries encounter many cross‐talk‐related challenges associated with liquid‐phase charge storage and rely on either mesoporous hosts or single‐ion conducting membranes to reversibly cycle without substantial shuttling [19c,26] . Hence, the long‐term cyclability of DIBs based on high energy halogen chemistries have yet to be realized in limited N/P ratio full‐cells.…”