Sustainable Utilization of Biomass Refinery Wastes for Accessing Activated Carbons and Supercapacitor Electrode Materials

Abstract

Biomass processing wastes (humins) are anticipated to become a large-tonnage solid waste in the near future, owing to the accelerated development of renewable technologies based on utilization of carbohydrates. In this work, the utility of humins as a feedstock for the production of activated carbon by various methods (pyrolysis, physical and chemical activation, or combined approaches) was evaluated. The obtained activated carbons were tested as potential electrode materials for supercapacitor applications and demonstrated combined micro- and mesoporous structures with a good capacitance of 370 F g (at a current density of 0.5 A g ) and good cycling stability with a capacitance retention of 92 % after 10 000 charge/discharge cycles (at 10 A g in 6 m aqueous KOH electrolyte). The applicability of the developed activated carbon for practical usage as a supercapacitor electrode material was demonstrated by its successful utilization in symmetric two-electrode cells and by powering electric devices. These findings provide a new approach to deal with the problem of sustainable wastes utilization and to advance challenging energy storage applications.

Humins from Biorefineries as Thermoreactive Macromolecular Systems

“…Valorization toward materials applications has been suggested, and it was demonstrated that humins improve the mechanical properties of thermosetting composites. Recently, other products, such as humins‐derived porous materials and active carbon, have also emerged, with possible applications such as sorbents and electrode materials. Several humins treatment processes have also been proposed, such as hydrotreatment, oxidation, and pyrolysis .…”

High‐Performance Plasma‐Enabled Biorefining of Microalgae to Value‐Added Products

“…The biochars were then applied as supercapacitor electrodes, and the electrochemical performances of as‐obtained biochar were tested by cyclic voltammetry (CV) and galvanostatic charge/discharge (GCD) measurements (Figure c and Figure S7). The CV curves of electrodes made of thermally upgraded biochar (OH − ‐SR‐Biochar) showed non‐ideal rectangular shapes compared to traditional carbon‐based electrode materials, such as the OH − ‐SR‐Activated Biochar electrodes, which produced CV curves with more rectangular shapes. The non‐ideal behaviour can arise owing to the existence of some non‐active materials in the biochar .…”

Recycled Red Mud–Decorated Porous 3D Graphene for High‐Energy Flexible Micro‐Supercapacitor

“…Carbon‐based materials are widely used in supercapacitors as they possess high surface area and electrical conductivity, [ 6 ] and there are abundant inexpensive sources with low environmental impact, such as biomass refinery waste, [ 7 ] graphite pencil trace, [ 8 ] and widely available polymers such as polyimide. [ 9 ] For example, Lin et al showed that treating polyimide (Kapton) films using a commercial infrared CO 2 laser photothermally converts CO, CO, and NC bonds into sp 2 bonded carbon, with 2D graphene sheets randomly stacked along the c ‐axis, [ 10 ] termed as laser‐induced graphene or LIG.…”