High-Entropy-Inspired Multicomponent Electrical Double Layer Structure Design for Stable Zinc Metal Anodes.

Regulating the electrical double layer (EDL) structure can enhance the cycling stability of Zn metal anodes, however, the effectiveness of this strategy is significantly limited by individual additives. Inspired by the high-entropy (HE) concept, we developed a multicomponent (MC) EDL structure composed of La3+, Cl-, and BBI anions by adding dibenzenesulfonimide (BBI) and LaCl3 additives into ZnSO4 electrolytes (BBI/LaCl3/ZnSO4). Specifically, La3+ ions accumulate within EDL to shield the net charges on the Zn surface, allowing more BBI anions and Cl- ions to enter this region. Consequently, this unique MC EDL enables Zn anodes to simultaneously achieve uniform electric field, robust SEI layer, and balanced reaction kinetics. Moreover, the synergistic parameter-a novel descriptor for quantifying collaborative improvement-was first proposed to demonstrates the synergistic effect between BBI and LaCl3 additives. Benefitting from these advantages, Zn metal anodes achieved a high reversibility of 99.5% at a depth of discharge (DoD) of 51.3%, and Zn|MnO2 pouch cells exhibited a stable cycle life of 100 cycles at a low N/P ratio of 2.9.

Synergistic effect between S and Te enhancing the electrochemical behavior of heteroatomic TeS-x cathodes in aqueous Zn-TeS batteries.

Aqueous Zn-S batteries (AZSBs) have garnered increasing attention in the energy storage field owing to their high capacity, energy density, and cost effectiveness. Nevertheless, sulfur (S) cathodes face challenges, primarily stemming from sluggish reaction kinetics and the formation of an irreversible byproduct (SO42-) during the charge, hindering the progress of AZSBs. Herein, Te-S bonds within S-based cathodes were introduced to enhance electron and ion transport and facilitate the conversion reaction from zinc sulfide (ZnS) to S. This was achieved by constructing heteroatomic TeS-x@Ketjen black composite cathodes (HM-TeS-x@KB, where x  = 36, 9, and 4). The HM-TeS-9@KB electrode exhibits long-term cycling stability, maintaining a capacity decay rate of 0.1 % per cycle over 450 cycles at a current density of 10 A g-1. Crucially, through a combination of experimental data analysis and theoretical calculations, the impact mechanism of Te on the charge and discharge of S active materials within the HM-TeS-9@KB cathode in AZSBs was investigated. The presence of Te-S bonds boost the intrinsic conductivity and wettability of the HM-TeS-9@KB cathode. Furthermore, during the charge, the interaction of preferentially oxidized Te with S atoms within ZnS promotes the oxidation reaction from ZnS to S and suppresses the irreversible side reaction between ZnS and H2O. These findings indicate that the heteroatomization of chalcogen S molecules represents a promising approach for enhancing the electrochemical performance of S cathodes in AZSBs.

Long Shelf-Life Efficient Electrolytes Based on Trace l-Cysteine Additives toward Stable Zinc Metal Anodes.

The unstable anode/electrolyte interface (AEI) triggers the corrosion reaction and dendrite formation during cycling, hindering the practical application of zinc metal batteries. Herein, for the first time, l-cysteine (Cys) is employed to serve as an electrolyte additive for stabilizing the Zn/electrolyte interface. It is revealed that Cys additives tend to initially approach the Zn surface and then decompose into multiple effective components for suppressing parasitic reactions and Zn dendrites. As a consequence, Zn|Zn symmetric cells using trace Cys additives (0.83 mm) exhibit a steady cycle life of 1600 h, outperforming that of prior studies. Additionally, an average Coulombic efficiency of 99.6% for 250 cycles is also obtained under critical test conditions (10 mA cm-2 /5 mAh cm-2 ). Cys additives also enable Zn-V2 O5 and Zn-MnO2 full cells with an enhanced cycle stability at a low N/P ratio. More importantly, Cys/ZnSO4 electrolytes are demonstrated to be still effective after resting for half year, favoring the practical production.

Stabilizing Zinc Anodes by Regulating the Electrical Double Layer with Saccharin Anions.

Zn anodes suffer from poor Coulombic efficiency (CE) and serious dendrite formation due to the unstable anode/electrolyte interface (AEI). The electrical double layer (EDL) structure formed before cycling is of great significance for building stable solid electrolyte interphase (SEI) on Zn surface but barely discussed in previous research about the stabilization of Zn anode. Herein, saccharin (Sac) is introduced as electrolyte additive for regulating the EDL structure on the AEI. It is found that Sac derived anions are preferentially adsorbed on the Zn metal surface instead of water dipole, creating a new H2 O-poor EDL structure. Moreover, the unique SEI is also detected on the Zn surface due to the decomposition of Sac anions. Both are proved to be capable of modulating Zn deposition behavior and preventing side reactions. Encouragingly, Zn|Zn symmetric cells using Sac additive deliver a high cumulative plated capacity of 2.75 Ah cm-2 and a high average CE of 99.6% under harsh test condition (10 mA cm-2 , 10 mAh cm-2 ). The excellent stability is also achieved at a high rate of 40 mA cm-2 . The effectiveness of this Sac additive is further demonstrated in the Zn-MnO2 full cells.