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

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 angstrom) 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. Therefor; 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.

Automated summary

The incorporation of La3+ ions into V2O5 cathodes can enhance Zn2+ diffusion kinetics and stabilize vanadium species, leading to improved cyclability and energy density of aqueous zinc-ion batteries. The La-V2O5 cathodes show exceptional rate capacity, long-term stability, and outstanding energy density, outperforming various metal-ion-doped V2O5 cathodes. Additionally, the La-V2O5 pouch cell exhibits excellent electrochemical performance, flexibility, and integration ability, providing guidance for other advanced electrochemical devices.