Interlayer co-chemistry of a homologous ion stabilizer and microenvironmental molecular regulator for high-performance zinc-ion storage

Abstract

Layered materials have been regarded as ideal electrodes for aqueous zinc-ion batteries (ZIBs) due to their flexible 2D structures. However, their electrochemical properties remain limited by sluggish Zn²⁺ transport and structural instability caused by unsatisfactory interlayer chemistry including small interlayer distances, strong electrostatic interactions and structure collapse. Herein, we propose an interlayer co-chemistry strategy that integrates homologous Zn²⁺ stabilizers with a dipolar molecular regulator, triethylene glycol (TEG), to construct a compatible and dynamic interlayer environment in hydrate vanadium pentoxide. Combined theoretical and experimental evidence confirms that pre-intercalated Zn²⁺ anchors the VO layers to stabilize the layered structure and forms predefined transport channels through the homologous ion effect, while TEG regulates the local electric field, lowers Zn²⁺ desolvation barriers, and promotes rapid diffusion. In addition, the oxygen-containing groups of TEG further provide reversible Zn-binding sites, contributing additional storage capacity. As a result, the (TEG, Zn)–VOH cathode delivers a high specific capacity of 460 mAh g⁻¹ at 0.1 A g⁻¹, excellent rate performance (301 mAh g⁻¹ at 5 A g⁻¹), and outstanding cycling stability (106% capacity retention after 10 000 cycles at 8 A g⁻¹).