Defect-rich BiOCl nanosheets for ultrahigh-rate aqueous alkaline batteries

Energy density and power density are critical parameters in energy storage devices. The development of “dual-high” (high energy and high power) electrode materials is a pivotal challenge in electrochemical energy storage. To achieve superior capacity retention during fast charging/discharging, this study utilizes a metal-organic framework (MOF) precursor combined with an ion-etching strategy to synthesize hierarchically porous BiOCl nanosheets (MOF-BiOCl) as an advanced anode material. The optimized MOF-BiOCl sample, featuring a nanosheet morphology, abundant oxygen vacancies, and enhanced electrical conductivity, delivers a high specific capacity of 351.4 mAh g −1 at 1 A g −1 while retaining 75% of its capacity (263.9 mAh g −1 ) under an ultrahigh current density of 20 A g −1 . Furthermore, the assembled BCNP//MOF-BiOCl aqueous alkaline battery (AAB) achieves an energy density of 138.9 Wh kg −1 at a power density of 1.1 kW kg −1 and maintains 80% of its initial capacity after 9000 cycles, demonstrating exceptional cycling stability. This study establishes a novel design paradigm for high-performance layered bismuth-based electrode materials and provides foundational insights into the development of advanced aqueous energy storage systems.