A composite of pineapple leaf-derived porous carbon integrated with ZnCo-MOF for high-performance supercapacitors†

Abstract

Electrochemical energy storage heavily depends on the activity and stability of electrode materials. However, the direct use of metal–organic frameworks (MOFs) as supercapacitor electrode materials poses challenges due to their low electrical conductivity. In this study, pineapple leaf-derived biochar (PLB) was employed as a carrier for bimetallic ZnCo-MOF, resulting in the composite ZnCo-MOF@PLB-800, synthesized through in situ growth and pyrolysis at 800 °C. The highly porous structure of PLB alleviated the aggregation of ZnCo-MOF particles, thereby enhancing the electron transfer rate and improving the conductivity of the electrode material. Electrochemical testing revealed that ZnCo-MOF@PLB-800 achieved a specific capacitance of 698.5 F g⁻¹ at a current density of 1 A g⁻¹. The assembled asymmetric supercapacitor (ASC) demonstrated excellent specific capacitance and electrochemical stability, delivering a high energy density of 35.85 W h kg⁻¹ at a power density of 350 W kg⁻¹, with robust cycle stability, retaining 90.4% capacitance after 8000 cycles. This work offers an effective integration of bimetallic MOFs with waste biomass-derived porous carbon for electrode materials, supporting both energy storage applications and environmental sustainability.