Enabling Stable Zn Anodes by Molecularly Engineering the Inner Helmholtz Plane with Amphiphilic Dibenzenesulfonimide Additive.

ABSTRACT: The notorious dendrite growth and hydrogen evolution reaction (HER) are considered as main barriers that hinder the stability of the Zn-metal anode. Herein, molecular engineering is conducted to optimize the inner Helmholtz plane with a trace of amphiphilic dibenzenesulfonimide (BBI) in an aqueous electrolyte. Both experimental and computational results reveal that the BBI^- binds strongly with Zn²⁺ to form {Zn(BBI)(H₂ O)₄ }⁺ in the electrical double layer and reduces the water supply to the Zn anode. During the electroplating process, {Zn(BBI)(H₂ O)₄ }⁺ is "compressed" to the Zn anode/electrolyte interface by Zn²⁺ flow, and accumulated and adsorbed on the surface of the Zn anode to form a dynamic water-poor inner Helmholtz plane to inhibit HER. Meanwhile, the{Zn(BBI)(H₂ O)₄ }⁺ on the Zn anode surface possesses an even distribution, delivering uniform Zn²⁺ flow for smooth deposition without Zn dendrite growth. Consequently, the stability of the Zn anode is largely improved with merely 0.02 M BBI^- to the common electrolyte of 1 M ZnSO₄ . The assembled Zn||Zn symmetric cell can be cycled for more than 1180 h at 5 mA cm^-2 and 5 mA h cm^-2 . Besides, the practicability in Zn||NaV₃ O₈ ·1.5 H₂ O full cell is evaluated, which suggests efficient storage even under a high mass loading of 12 mg cm^-2 .

SUBMITTER: Yang J 

PROVIDER: S-EPMC10401170 | biostudies-literature | 2023 Aug

REPOSITORIES: biostudies-literature