Two Birds with One Stone: Boosting Zinc-Ion Insertion/Extraction Kinetics and Suppressing Vanadium Dissolution of V₂O₅ via La³⁺ Incorporation Enable Advanced Zinc-Ion Batteries

Abstract

Aqueous zinc-ion batteries (ZIBs) with cost-effective and safe features are highly competitive in grid energy storage applications, but plagued by the sluggish Zn²⁺ diffusion kinetics and poor cyclability of cathodes. Herein, a one-stone-two-birds strategy of La³⁺ incorporation (La-V₂O₅) is developed to motivate Zn²⁺ insertion/extraction kinetics and stabilize vanadium species for V₂O₅. Theoretical and experimental studies reveal the incorporated La³⁺ ions in V₂O₅ can not only serve as pillars to expand the interlayer distance (11.77 Å) and lower the Zn²⁺ migration energy barrier (0.82 eV) but also offer intermediated level and narrower band gap (0.54 eV), thus accelerating the electron/ion diffusion kinetics. Importantly, the steadily doped La³⁺ ions effectively stabilize the V-O bonds by shortening the bond length, thereby inhibiting vanadium species dissolution. Therefore, the resulting La-V₂O₅-ZIBs deliver an exceptional rate capacity of 405 mA h g^-1 (0.1 A g^-1), long-term stability with 93.8% retention after 5000 cycles (10 A g^-1), and extraordinary energy density of 289.3 W h kg^-1, outperforming various metal-ions-doped V₂O₅ cathodes. Moreover, the La-V₂O₅ pouch cell presents excellent electrochemical performance and impressive flexibility and integration ability. The strategies of incorporating rare-earth-metal ions provide guidance to other well-established aqueous ZIBs cathodes and other advanced electrochemical devices.