Preparation of high-performance, three-dimensional, hierarchical porous carbon Supercapacitor materials and high-value-added potassium Humate from cotton stalks

Abstract

Although the resource utilization of organic solid waste from biomass (OSWB) has been investigated, it is difficult to completely utilize such resources using the existing methods. Therefore, the development of a comprehensive application method would be very significant. Here, a simple process using chemical oxidation of H2O2 was initially developed to prepare potassium humate (HA-K) from cotton stalk peels. Subsequently, we obtained three-dimensional hierarchical porous carbon (3D-HPC) materials by carbonizing and activating the residue after HA-K extraction. Chemical oxidation achieved the effect of “killing two birds with one stone” because it increased the HA-K yield by 40% and the capacitance of the electrode based on 3D-HPC (3OCA-500-650). Compared with the electrode without chemical oxidation, the obtained 3OCA-500-650 exhibited higher specific capacitance (420 F g−1 at 0.5 A g−1), enhanced an energy density (58 Wh kg−1 at a power density of 1300 W kg−1). This work provides a green, facile technology to achieve full utilization of OSWB, which is expected to be effective and scalable for preparing HA-K and electrochemical energy storage materials exhibiting excellent performance.