Ferroelectric small molecule enabled high-performance zinc-ion batteries.

To address the challenges of zinc-anode corrosion, hydrogen evolution reactions and dendrite growth in aqueous zinc-ion batteries, we introduce tetraethylammonium perchlorate (TEACC) as ferroelectric small molecules additives in an aqueous electrolyte. The TEACC molecules partially replace water molecules in the Zn solvation sheath and enrich the electrode/electrolyte interface with TEACC-OTf, creating a water-deficient inner Helmholtz plane. As a result, the activity of free water is suppressed and the hydrogen-evolution potential shifts from -0.124 V to -0.271 V Zn/Zn. This interfacial restructuring also facilitates the formation of a stable solid electrolyte interphase (SEI) consisting of ZnCO, ZnCl and ZnS compounds, promoting highly reversible Zn plating/stripping with the coulombic efficiency exceeding 99.5%. Furthermore, the inherent ferroelectric properties of TEACC generate localized electric fields that help homogenize the distribution of Zn across the electrode surface. This effectively suppresses dendritic growth and reduces the Zn nucleation overpotential by 35 mV. Electrochemical evaluation of full cells with Zn‖TBABr demonstrated impressive performance, with 92.94% capacity retention after 380 cycles at 1.25 A g and excellent rate capability across current densities from 0.5 to 3 A g. The system's practical applicability was further validated through flexible pouch cell configurations, where two series-connected cells powered 32 commercial LED indicators, showcasing the potential of this approach for flexible energy storage devices. Overall, the findings not only present a promising strategy for stabilizing zinc anode interfaces but also highlight the potential of ferroelectric molecular additives in advanced aqueous battery systems.