Redox molecule Alizarin red S anchored on biomass-derived porous carbon for enhanced supercapacitive performance

Abstract

Benefiting from its large specific surface area and hierarchical pore structure, biomass-derived porous carbon is widely used as an electrode material for energy storage devices. In this research, ginkgo leaves are used as a precursor and KOH as an activator to prepare porous carbon (KGL). The anthraquinone-type anionic dye molecule Alizarin red S (ARS) is anchored on porous carbon via two adsorption methods. ARS plays a crucial role in enhancing the electrochemical properties. KGL has larger adsorption capacity for ARS through electric field assisted adsorption compared with physical adsorption and more favorable electrochemical performance. KGL/ARS exhibits superior specific capacitance and rate performance because the redox reaction of ARS and porous carbon provides a stable conductive scaffold. The KGL/ARS-E5 electrode possesses a specific capacitance of 638.2 F g⁻¹ at 1 A g⁻¹ and the capacitance retention reaches 77.9% at 10 A g⁻¹. The assembled asymmetric supercapacitor exhibits an energy density of 24.8 W h kg⁻¹ at a power density of 801.4 W kg⁻¹, and the capacitance retention of the device is 93.5% after 10 000 cycles. The research provides a novel method to achieve a combination of porous carbon and redox-enhanced materials as the electrode for supercapacitors and realizes the recycling of carbonous adsorbents containing the redox species.