Solvothermal synthesis and electrochemical performance of BiOBr nanosheets for symmetric supercapacitor devices.

Bismuth-containing compounds have attracted considerable interest in electrochemical energy storage owing to their distinctive layered structures and favorable redox features. However, systematic studies on bismuth oxybromide (BiOBr) as an electrode materials for supercapacitors remain limited, despite its promising layered architecture that an facilitate ion transport and offer abundant active sites. In this study, we report the solvothermal preparation of BiOBr nanostructures with a unique curved sheet-like morphology, specifically designed to improve electrochemical activity. The fabricated BiOBr electrode demonstrated a high capacity of 84.6 mAh/g at 1.1 A/g, along with notable cycling stability. Furthermore, the assembled symmetric supercapacitor exhibited a notable energy density (Ed) of 10 Wh/kg at a power density (Pd) of 750 W/kg, while retaining  98% of its original capacitance over 3000 continuous runs. These findings highlight the potential of BiOBr-based electrodes as effective and durable materials for next-generation supercapacitor technologies.