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

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.

Automated summary

This study presents a versatile surface-grafting strategy of molecular brushes to construct a stable ion-regulating interface for Zn metal batteries, which addresses the issues of dendrite growth and low cycling efficiency. The designed interface features dense sulfo-terminated nanochannels that serve as ion-redistributors, homogenizing the flux of Zn2+ across the interface and accelerating the deposition kinetics. The Zn anode with this interface demonstrates high Coulombic efficiency and ultralong cyclability, making it a promising candidate for high-rate and long-life Zn-metal batteries.