Porous carbon derived from sodium alginate-encapsulated ZIF-8 for high-performance supercapacitor

• Sandwich-like porous carbon derived from sodium alginate-encapsulated ZIF-8 was prepared. • The introduction of a carbon framework on ZIF-8-derived particles effectively enhanced the electrochemical property. • The optimized sample exhibited a specific capacitance of up to 208 f g -1 at 0.5 a g -1 . Porous carbons hold broad application prospects in the domains of electrochemical energy storage devices and sensors. In this study, porous carbon derived from sodium alginate-encapsulated ZIF-8 (SA/ZIF-8-C) was successfully prepared by blending ZIF-8 particles with sodium alginate, forming hydrogel beads in the presence of divalent metal ions, and subsequently subjecting them to high-temperature pyrolysis. Various characterization techniques were employed to evaluate the properties of the prepared materials. The introduction of a carbon framework on ZIF-8-derived particles effectively enhanced the conductivity of the prepared materials. The SA/ZIF-8(1.0)-C sample heated at 800 °C exhibited a specific capacitance of up to 208 F g⁻¹ at a current density of 0.5 A g⁻¹ and outstanding cyclic stability. Even after 10,000 charge and discharge cycles, its capacitance retention rate remained as high as 87.14 %. The symmetric supercapacitor constructed with the composite demonstrated an excellent energy density of 14.58 Wh kg⁻¹ at a power capacity of 403.85 W kg⁻¹. The implementation of this study provides new ideas and inspiration for the development of high-performance supercapacitors. Sandwich-like porous carbon derived from sodium alginate-encapsulated ZIF-8 was successfully prepared. The specific capacitance reached up to 208 F g -1 at 0.5 A g -1 compared with ZIF-8-derived electrode materials lacking an interconnected carbon framework (ZIF-8-C) and sodium alginate-derived interconnected porous carbon (SA-C).