Manipulating Electric Double Layer Adsorption for Stable Solid‐Electrolyte Interphase in 2.3 Ah Zn‐Pouch Cells

Abstract Constructing a reliable solid‐electrolyte interphase (SEI) is imperative for enabling highly reversible zinc metal (Zn 0 ) electrodes. Contrary to conventional “bulk solvation” mechanism, we found the SEI structure is dominated by electric double layer (EDL) adsorption. We manipulate the EDL adsorption and Zn 2+ solvation with ether additives (i.e. 15‐crown‐5, 12‐crown‐4, and triglyme). The 12‐crown‐4 with medium adsorption on EDL leads to a layer‐structured SEI with inner inorganic ZnF x /ZnS x and outer organic C−O−C components. This structure endows SEI with high rigidness and strong toughness enabling the 100 cm 2 Zn||Zn pouch cell to exhibit a cumulative capacity of 4250 mAh cm −2 at areal‐capacity of 10 mAh cm −2 . More importantly, a 2.3 Ah Zn||Zn 0.25 V 2 O 5 ⋅ n H 2 O pouch cell delivers a recorded energy density of 104 Wh L cell −1 and runs for >70 days under the harsh conditions of low negative/positive electrode ratio (2.2 : 1), lean electrolyte (8 g Ah −1 ), and high‐areal‐capacity (≈13 mAh cm −2 ).