Water-shielding electric double layer and stable interphase engineering for durable aqueous zinc-ion batteries

Aqueous zinc-ion batteries persistently encounter interface issues stemming from the water-rich electrical double layer and unstable solid-electrolyte interphase, drastically compromising reversibility and cyclability. Here we show that trace amounts of nonionic amphiphilic polysorbate additives promote the formation of water-shielding electric double layer and stabilize solid-electrolyte interphase for practical zinc-ion batteries. We demonstrate that polysorbate molecules can produce preferential chemisorption and directional arrangement on the Zn anode, spontaneously forming water-shielding layer to suppress the water-related side reactions. Simultaneously, polysorbate molecules can assist the construction of organic-inorganic hybrid interphase, which effectively regulates the uniform distribution of electric field and guides preferential orientation Zn deposition to achieve ordered plating/stripping with high Zn utilization. Consequently, the polysorbate-containing electrolyte enables a long cycle life of 8060 h at 1 mA cm−2, 1 mAh cm−2 for Zn||Zn cell, and highly reversible Zn plating/stripping in Zn||Cu cell over 3900 cycles. The full cells paired with V2O5/rGO and MnO2 deliver the improved capacity and sustained stability. Aqueous Zn-ion batteries face challenges from water-induced reactions and unstable interfaces, drastically compromising their reversibility and cyclability. Here, authors introduce trace nonionic polysorbate additives to promote the formation of water-shielding double layer and to stabilize solid electrolyte interphase, achieving stable Zn-ion batteries.