Bismuth oxychloride-bismuth oxide hybrid as a high-capacity anode material for aqueous alkaline battery.

A high-capacity and rate capability anode material is highly desired to improve the export performance of aqueous alkaline batteries (AABs). Due to the 3-electrons redox chemistry within a wide negative potential range, bismuth (Bi) based compounds are promising candidates as anode materials in AABs. A hybrid composed of different Bi-based compounds is envisioned to further reinforce the faradaic activity and affinity for electrolyte ions, thereby maximizing the charge storage capacity. Herein, a bismuth oxychloride-bismuth oxide hybrid, denoted as BiOCl-BiO, was synthesized by solvothermal reaction followed by annealing treatment. The formation of hybrid substantially enhanced the faradaic reaction activity and kinetics, achieving a decent specific capacity (C) of 250 mAh/g at 1 A/g and rate capability (200 mAh/g at 5 A/g) in the negative potential range. The AAB based on the BiOCl-BiO hybrid anode delivered a high energy density (E) of 89.5 Wh kg at a power density (P) of 771 W kg, showcasing the charge storage and export capabilities of the BiOCl-BiO anode material in AABs. The current work provides a viable paradigm for designing a high-capacity Bi-based anode material for AABs.