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.

Low Current‐Density Stable Zinc‐Metal Batteries Via Aqueous/Organic Hybrid Electrolyte

“…More importantly, the pouch cell showed good cycling performance with a capacity of 109.9 mAh g À 1 after 500 cycles under a current density of 0.5 A g À 1 . Zn/HVO pouch cells exhibits superior capacity retention than that of other Zn/vanadium pouch cells in previous reports, such as Zn/NaV 3 O 8 • 1.5H 2 O batteries with gelation electrolyte, [50] Zn/La-V 2 O 5 batteries with 1 m ZOT aqueous electrolyte [51] and Zn/vanadium oxides with 4 m ZOT aqueous electrolyte [52] and so on (Table S4).…”

Recent Developments and Challenges of Vanadium Oxides (VxOy) Cathodes for Aqueous Zinc‐Ion Batteries

“…(b) Zn 2+ diffusion energy barriers of V 2 O 5 and La 3+ −V 2 O 5 . Reproduced with permission [66] . Copyright 2021, American Chemical Society.…”

“…[64,65] The extraordinary electrochemical properties of the whole structure stem from the free insertion and detachment of Zn 2 + . Nonetheless, the low electrical conductivity of V 2 O 5 hindered its large-scale development, so enhancing the electronic conductivity is crucial (common modification methods such as the incorporation of La 3 + ions, [66] construction of oxygen defects, [67] etc. The specific methods of improvement will be thoroughly described later).…”

“…Recently, Huang et al [66] . presented a La 3+ ‐incorporated strategy, which optimized the kinetics of Zn 2+ extraction/insertion and stabilized the vanadium species for V 2 O 5 .…”

Strategies of regulating Zn2+solvation structures for dendrite-free and side reaction-suppressed zinc-ion batteries

“…16–22 In a typical prototype, ZIBs consist of zinc metal anodes, (in)organic cathodes, neutral or slightly acidic aqueous electrolytes and separators. Thus far, great research efforts have been devoted to exploring advanced cathode materials for ZIBs and tremendous available materials have been developed for Zn 2+ ion storage such as manganese-based compounds, 23–28 vanadium-based compounds, 29–32 Prussian blue analogues 33,34 and some emerging materials. 18,35–39 In addition, the redox mechanisms of ZIBs have been demonstrated to be based on intercalation-type or conversion-type.…”