Durable porous carbon/ZnMn2O4 composite electrode material for supercapacitor

A series of porous carbon/zinc dimanganese (ZnMn2O4) composites was successfully synthesized through low temperature combustion of zinc chloride (ZnCl2) activated pineapple peel (PP) and MnCO3 at 500 degrees C. The incorporation of manganese carbonate (MnCO3) played a vital role in modifying the pore shape and size of the sample which enhanced the rate capability and stability through the synergistic effect of carbon and ZnM2O4. Highest specific surface area of 976.12 m(2) g(-1) for porous carbon/ZnMn2O4 composite was obtained. The composite samples were further examined for its electrochemical performance and observed that PPZn-Mn1 achieved the specific capacitance of 104.89 Fg(-1) while 119.03 Fg(-1) in PPZn at the current density of 300 mA g(-1). PPZn-Mn1 exhibited better rate capability and cycleability with capacitance retention at 97.06% after 5000 cycles as compared to PPZn composite which dropped to 79.52%. A symmetrical cell imposed similar characteristic which 83.89% of the capacitance was retained after 5000 cycles at 300 mA g(-1). Thus, the incorporation of ZnMn2O4 in this composite has highlighted its role as the supporting element to enhance the performance in cycleability and durability test. (C) 2019 Elsevier B.V. All rights reserved.