A Covalent Black Phosphorus/Metal–Organic Framework Hetero-nanostructure for High-Performance Flexible Supercapacitors

We develop hetero-nanostructured black phosphorus/metal-organic framework hybrids formed by P-O-Co covalent bonding based on a designed droplet microfluidic strategy consisting of confined and ultrafast microdroplet reactions. The resulting hybrid exhibits large capacitance (1347 F g⁻¹) in KOH electrolytes due to its large specific-surface-area (632.47 m² g⁻¹), well-developed micro-porosity (0.38 cm³ g⁻¹), and engineered electroactivity. Furthermore, the proposed 3D printing method allows to construct all-integrated solid-state supercapacitor, which maintains interconnected porous network, good interfacial adhesion, and robust flexibility for short-path diffusion and excessive accommodation of ions. Consequently, the fabricated flexible supercapacitor delivers ultrahigh volumetric energy density of 109.8 mWh cm⁻³, large capacitance of 506 F cm⁻³, and good long-term stability of 12000 cycles.