Molecular brush: an ion-redistributor to homogenize fast Zn2+ flux and deposition for calendar-life Zn batteries

Abstract

Aqueous Zn metal batteries hold promising prospects for stationary energy storage technology, but the aggravating dendrite growth and low cycling efficiency of Zn metal anodes caused by the unstable Zn–electrolyte interface substantially retards their real-world applications. Herein, we propose a versatile surface-grafting strategy of molecular brushes to rationally construct a robust and lightweight ion-regulating interface toward ultrastable Zn anodes. The dense sulfo-terminated nanochannels of the molecular brush could serve as an ion-redistributor for homogenizing the Zn²⁺ flux across the interface with high transference and expediting the deposition kinetics by depressing the desolvation barrier of hydrated Zn²⁺. The as-designed interface enables the Zn anode to exhibit a high Coulombic efficiency of up to 99.9% for 900 cycles and ultralong cyclability over 2500 h under a high rate of 10 mA cm⁻² (i.e., an unprecedented cumulative plated capacity of 12.5 A h cm⁻²). Moreover, practical enhancements of the superior rate/cycling performance are demonstrated in Zn–MnO₂ full cells. This study paves a new yet powerful tactic for designing a functional molecular brush-grafted interface toward high-rate and calendar-life Zn–metal batteries.