Sieving‐type Electric Double Layer with Hydrogen Bond Interlocking to Stable Zinc Metal Anode

Abstract

Abstract The stability of aqueous zinc metal batteries is significantly affected by side reactions and dendrite growth on the anode interface, which primarily originate from water and anions. Herein, we introduce a multi H‐bond site additive, 2, 2′‐Sulfonyldiethanol (SDE), into an aqueous electrolyte to construct a sieving‐type electric double layer (EDL) by hydrogen bond interlock in order to address these issues. On the one hand, SDE replaces H 2 O and SO 4 2− anions that are adsorbed on the zinc anode surface, expelling H 2 O/SO 4 2− from the EDL and thereby reducing the content of H 2 O/SO 4 2− at the interface. On the other hand, when Zn 2+ are de‐solvated at the interface during the plating, the strong hydrogen bond interaction between SDE and H 2 O/SO 4 2− can trap H 2 O/SO 4 2− from the EDL, further decreasing their content at the interface. This effectively sieves them out of the zinc anode interface and inhibits the side reactions. Moreover, the unique characteristics of trapped SO 4 2− anions can restrict their diffusion, thereby enhancing the transference number of Zn 2+ and promoting dendrite‐free deposition and growth of Zn. Consequently, utilizing an SDE/ZnSO 4 electrolyte enables excellent cycling stability in Zn//Zn symmetrical cells and Zn//MnO 2 full cells with lifespans exceeding 3500 h and 2500 cycles respectively.