High-mass loading Bi2O2CO3 nanoflakes with crystalline structure transition as cathode for alkaline zinc battery

Rechargeable aqueous alkaline zinc batteries (AZBs) have received extensive attention due to their cost-effectiveness and environmental friendliness. However, the areal capacity of currently reported AZBs is still unsatisfactory especially at high mass loading, which hinders their further practical application. Herein, we propose a simple precipitate strategy to prepare low-cost Bi2O2CO3 nanoflakes for AZBs. The resultant Bi2O2CO3 undergoes a structural transformation during the charge/discharge cycle, which not only significantly changed the microstructure but also optimized the energy storage capability of the as-prepared material. At a high mass loading of 30 mg cm(-2), the as-fabricated electrode could attain a high areal capacity of 5.14 mAh cm(-2) at the current density of 15 mA cm(-2), excellent rate capability (2.40 mAh cm(-2) at 180 mA cm(-2)), and long cycling life of about 88.6% retention after 800 charge/discharge cycles. Ex situ XRD and SEM techniques show that the energy storage mechanism of the prepared material is predominantly contributed by the reversible conversion reaction between Bi and Bi2O3 in the KOH aqueous electrolyte. This work might shed light on the construction of advanced materials in alkaline energy-storage devices.

Automated summary

In this study, low-cost Bi2O2CO3 nanoflakes were prepared using a simple precipitate strategy for rechargeable aqueous alkaline zinc batteries. The as-prepared material exhibited high areal capacity, excellent rate capability, and long cycling life. The energy storage mechanism was found to be predominantly contributed by the reversible conversion reaction between Bi and Bi2O3 in the KOH aqueous electrolyte. This work is of great importance for the construction of advanced materials in alkaline energy-storage devices.