Zinc gluconate derived porous carbon electrode assisted high rate and long cycle performance supercapacitor

Abstract

The low energy density of supercapacitor is the main reason that limits the utilization of multifunction. Based on this, it is particularly necessary to establish porous network structure electrode for understanding the energy storage mechanism of advanced supercapacitors. In this work, the strategy of activated zinc gluconate was proposed to prepare porous carbon with different pore structures. The as-prepared zinc gluconate derived activated porous carbon (ZnPCK-3) has rich porous network structure with high specific surface area of 1973 m2 g−1 and microporous pore sizes of 1.9 nm exposing abundant electrochemical active sites. Benefiting from the microstructure promotes the storage of electrolyte ions, the ZnPCK-3 electrode shows excellent rate performance of 143 F g−1 at a current density of 20 A g−1. The symmetrical supercapacitor with obtained ZnPCK-3 electrode assembly achieves energy density of ∼92.6 Wh kg−1 in Et4NBF4 electrolyte and specific capacitance retention of 94.5 % after 10,000 cycles at the current density of 20 A g−1. The proven zinc gluconate assisted strategy affords emerging chances for rational commercial-level design for high performance supercapacitor.