Design and synthesis of organic radical functionalized vanadium pentoxide towards long-life aqueous zinc ion batteries

Abstract

The V₂O₅ cathode material has attracted considerable attention for rechargeable aqueous zinc-ion batteries (ZIBs) owing to the rich redox chemistry of vanadium. However, the cycling performance of the V₂O₅ cathode is still hampered by the sluggish Zn²⁺ diffusion kinetics. Herein, we employed a facile “two-in-one” strategy to fabricate organic radical functionalized V₂O₅ (V₂O₅-TEMPO) via selecting 2,2,6,6-tetramethylpiperidine 1-oxyl (TEMPO) as the nitroxide monomer and riveting it onto V₂O₅ and we applied it as the cathode of rechargeable aqueous zinc-ion batteries. Benefitting from the large specific area and the porous structure of V₂O₅-TEMPO cathode materials, V₂O₅-TEMPO achieved a large specific capacity of 327.4 mA h g⁻¹ at 0.1 A g⁻¹ and impressive cycling performance with a capacity retention of 90.8% after 5500 cycles at 2.0 A g⁻¹. In addition, the reversible storage mechanism of Zn²⁺ was further studied by using kinetic analysis and density functional theory (DFT) calculations. This work provides key insights into the design and fabrication of organic radical compound-based cathode materials for constructing high-performance rechargeable aqueous multivalent ion batteries.