Self-Adaptive Hierarchical Hosts with Switchable Repulsive Shielding for Dendrite-Free Zinc-Ion Batteries

The engineering of anode-electrolyte interphase for highly reversible and dendrite-free Zn plating-stripping continues to pose a significant challenge in the progression of aqueous Zn-ion batteries (AZIBs). In this study, a novel approach is introduced that involves the design of a hierarchical carbon nanotube (CNT)-based host through functionalization with cetyltrimethylammonium cations (CTA⁺). This hierarchical host enables dynamically switchable repulsive shielding to regulate Zn plating. The CNT scaffold, featured with high flexibility and conductivity, facilitates expandable accommodation of continuous Zn plating. Concurrently, the entangled CTA⁺ cations, acting as manipulators to form switchable repulsive shields, dynamically suppress the growth of Zn dendrites, and result in uniform Zn plating within cationic CNT (C-CNT) hosts. The cationic shielding effect is further elucidated through density functional theory calculations. By incorporating the self-adaptive C-CNT host, Zn symmetric cells exhibit an impressively stable cycling lifespan exceeding 6500 h at 1 mA·cm⁻² and achieve a cumulative capacity of 6000 mAh·cm⁻² at 4 mA·cm⁻². Full batteries, by coupling the C-CNT@Zn anode and MnO₂ cathode, demonstrate an 88% capacity retention after 2000 cycles at 2 A·g⁻¹. The design of the self-adaptive C-CNT host offers a promising approach in electrode-electrolyte interphase engineering toward the practical applications of Zn-based energy storage systems.