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 (Zn⁰ ) 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 Zn²⁺ 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 cm² 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 V₂ O₅ ⋅n H₂ 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 ).