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.
Keywords: La3+ incorporation; V2O5 cathode; energy barrier; vanadium dissolution; zinc-ion battery.