Constructing Robust Hydrogen Bond Networks in Electrolytes for Long-Life Zinc-Ion Batteries

Hydrogen bonding in the aqueous electrolyte of zinc-ion batteries is a key factor dominating cycling stability due to the corrosive effects of water on both anode and cathode. Herein, we designed a robust, continuous hydrogen-bond network using ethylene glycol as a cosolvent and sulfate ion (SO₄ ^2-) as structure-making anion. Both hydrogen (H) and oxygen (O) atoms of water and ethylene glycol in the electrolyte are inter-anchored to mitigate the attack of O on a vanadium-based cathode and the attack of H on the zinc (Zn) anode. Furthermore, the entry of ethylene glycol into the Zn²⁺ solvation structure facilitates Zn²⁺ intercalation and improves the reversibility of byproducts arising from H⁺-insertion. As a result, excellent cycling performances was achieved in coin cells, with capacity retentions of 87% after 500 cycles at 0.5 A g^-1 and 95% after 150 cycles at 0.2 A g^-1, ranking among the highest cycling stabilities reported to date. Moreover, a pouch cell with an area of 90 cm² delivered a substantial capacity of 2 Ah and maintained 80% capacity retention after 70 cycles, highlighting the strong potential for practical scalability.