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 Bi₁₂O₁₇Cl₂-Bi₂O₃, 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_s) 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 Bi₁₂O₁₇Cl₂-Bi₂O₃ hybrid anode delivered a high energy density (E_cell) of 89.5 Wh kg^-1 at a power density (P_cell) of 771 W kg^-1, showcasing the charge storage and export capabilities of the Bi₁₂O₁₇Cl₂-Bi₂O₃ anode material in AABs. The current work provides a viable paradigm for designing a high-capacity Bi-based anode material for AABs.