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

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 ZnFx /ZnSx 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||Zn0.25 V2 O5 ⋅n H2 O pouch cell delivers a recorded energy density of 104 Wh Lcell -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 ).