Metal‐Organic Framework‐Templated Synthesis of 2D Co ₃ S ₄ @Co‐BPDC Nanosheets for High‐Performance Electrochemical Energy Storage

ABSTRACT Two‐dimensional (2D) metal‐organic framework (MOF) nanosheets have been widely applied in energy storage. However, single‐component MOF nanosheets face limitations in large‐scale applications due to their poor conductivity and insufficient stability. Therefore, the development of MOF‐based composite nanosheets with enhanced conductivity and stability through the incorporation of a second component has attracted widespread attention. In this work, a series of petal‐like 2D Co ₃ S ₄ @Co‐BPDC composite nanosheets were synthesized by a MOF‐templated synthesis method. Combining the high specific surface area and porous properties of MOF with the excellent stability and conductivity advantages of metal sulfides, the Co ₃ S ₄ @Co‐BPDC‐3 electrode without binders and conductive additives demonstrates an exceptional capacity of 2589.2 F·g ⁻¹ at 1.0 A·g ⁻¹ , coupled with a good cycling stability of 90.5% capacity retention after 1000 cycles. The coin‐type asymmetric supercapacitor (ASC) device displays a maximum energy density of 110.4 Wh·kg ⁻¹ at a power density of 1699.9 W·kg ⁻¹ , retaining 92.1% capacitance after 10 000 cycles. Furthermore, the flexible ASC device delivers 45.1 Wh·kg ⁻¹ energy density at 1500.3 W·kg ⁻¹ with 81.8% retention after 5000 cycles, maintaining 94.4% capacity even under 180° bending. This work established a MOF‐templated synthesis method for 2D composite nanosheets, enabling a rational design strategy toward high‐performance 2D energy storage materials.