Spatio-dipolar synergy modulated interfacial molecular bridge for calendar-aging-resistant aqueous zinc-ion batteries

Short calendar-aging life and interfacial degradation hinder the applications of aqueous Zn-ion batteries. Herein, trimorpholinophosphine oxide (TPO), featuring a high topological polar surface area (TPSA), is introduced as an electrolyte additive that modulates interfacial ions via steric-dipolar synergism. Specifically, the topological polarity of TPO facilitates Zn²⁺ coordination and strong surface adsorption, creating migration channels within solvation-interfacial networks. Moreover, the steric hindrance of TPO disrupts the solvation sheath of Zn²⁺, forming H₃O⁺-repelled layers. Consequently, TPO-containing cells achieve an exceptional average Coulombic efficiency (CE) of 99.91% and operate steadily at ultrahigh current densities (280 mA cm^-2). At -20°C, TPO-containing cells retain 177 mAh g⁻¹ after 6000 cycles, yet additive-free cells fail after 1400 cycles (84 mAh g⁻¹). Most importantly, TPO-containing cells maintain a high CE exceeding 95% for over 2500 h under intermittent calendar-aging, far exceeding the 72 h of additive-free cells. This work offers molecular-level insights into TPSA-induced steric-dipole synergism for ultra-stable batteries.