Defective 1T-VS2 with fibonacci pattern unlocking high mass-loading and self-charging cathodes for aqueous zinc-ion batteries†

Abstract

Cathode materials that exhibit high capacity, rapid charging, and long lifespan at high mass loading are crucial for the commercialization of aqueous zinc-ion batteries (AZIBs). However, challenges such as sluggish electrochemical kinetics and structural degradation during cycling often lead to low specific capacity and poor cycling stability, especially under high mass loading conditions, hindering their practical application. In this study, we introduce a novel defective 1T-VS₂ micro-rose material with a Fibonacci golden pattern structure, engineered to optimize the electrochemical performance of AZIBs. The unique rose-like morphology of the material promotes both a uniform and enriched electric field and concentration distribution, facilitating efficient ion and electron transport. This architecture, combined with abundant sulfur vacancies and vanadium intercalation, enhances structural stability, reduces cation migration barriers, and accelerates electrochemical kinetics. At high mass loading (up to 30 mg cm⁻²), the defective 1T-VS₂ cathode demonstrates excellent capacity retention (220 mA h g⁻¹, 83% retention), remarkable cycling stability (80% retention over 400 cycles at 20 mA cm⁻²), and superior rate capability. Notably, the material also exhibits outstanding self-charging performance, with a high self-charging efficiency and an impressive self-charging rate, even at a high mass loading of 10 mg cm⁻². This work not only underscores the exceptional electrochemical properties of the defective 1T-VS₂ cathode but also presents a design strategy that integrates macro-to-micro-scale structural optimization, offering a promising direction for the development of high-performance cathodes in energy storage applications.