Decoupling electronic and crystal structure effects to overcome the capacity-stability trade-off for high-performance aqueous zinc-ion batteries

Abstract

Aqueous zinc-ion batteries (ZIBs) with high capacity and long cycling stability are largely hindered by sluggish Zn²⁺ diffusion kinetics and irreversible cathode dissolution. Herein, electron delocalization is manipulated in vanadium oxides intercalated with organic tetrabutylammonium (TBA⁺) and inorganic Zn²⁺ cations, decoupling the relationship between electronic/crystal structure and electrochemical property, effectively unlocking the intrinsic trade-off between capacity and cycling stability. The synergistic intercalation of TBA⁺ and Zn²⁺ generates V─O─TBA and V─O─Zn coordination bonds, inducing charge redistribution and delocalizing electrons in the V 3d−O 2p hybridized orbitals, thereby optimizing the electronic structure and facilitating charge transport. Furthermore, TBA⁺ intercalating expands the interlayer spacing, reducing the Zn²⁺ diffusion energy barrier and activation energy, while Zn²⁺ incorporation alleviates lattice strain through strong Zn²⁺−O²⁻ interaction, stabilizing the layered structure during cycling. Thus, such a promising cathode delivers a high discharge specific capacity of 424 mAh g⁻¹ at 0.1 A g⁻¹, exceptional rate capability (320 mAh g⁻¹ at 5 A g⁻¹), and 89% retention after 3000 cycles. The study provides a design framework for synergistic regulations of electronic and ionic properties in layered oxides, advancing the development of high-performance ZIBs cathodes.