MOF-derived hierarchical Bi2O3 as advanced anode for Ni/Bi alkaline battery with high energy density

As a promising anode material, Bi2O3 has triggered great attention due to the combined advantages of high theoretical capacity, wide potential window and highly reversible redox process. However, the limited active sites and poor conductivity make the actual capacity of Bi2O3 far from satisfaction, which greatly hinder its practical application in aqueous alkaline battery. Herein, a novel Bi-MOF derived hierarchical structured Bi2O3 is synthesized via controlling the calcination conditions. The N2 adsorption-desorption analysis indicates the large specific surface area (9.68 m2 g−1) and porous structure of hierarchical Bi2O3. The electrochemical experiments reveal that the hierarchical Bi2O3 delivers a high specific capacity of 219.4 mAh g−1 at 1 A g−1 and long-term stability of 83% after 2000 cycles. Such remarkable electrochemical performance generates from the full utilization of exposed active sites, fast diffusion of electrolytes and steady hierarchical structure. Apart from this, the assembled Ni/Bi aqueous alkaline battery also exhibits outstanding electrochemical performance and a high energy density of 36.8 Wh kg−1 is achieved at 400.1 W kg−1. This work may pave the way for exploring Bi-based high-performance anode materials for alkaline battery.