The global shift toward sustainable energy storage is elevating the importance of technologies like supercapacitors, which bridge the performance gap between conventional capacitors and batteries by offering exceptional power density and long lifespan. Crucially, supercapacitors offer a more eco-friendly alternative to traditional batteries, often avoiding the use of scarce and environmentally damaging materials like cobalt and lithium in favor of abundant carbon-based electrodes. A key focus in this field is the valorization of abundant waste materials into high-performance electrode materials, aligning with the principles of the circular bioeconomy. A recent study published in BiomassBiomass is a complex biological organic or non-organic solid product derived from living or recently living organism and available naturally. Various types of wastes such as animal manure, waste paper, sludge and many industrial wastes are also treated as biomass because like natural biomass these More and Bioenergy by Lobato-Peralta et al. specifically investigated the synthesis of high-performance activated carbons from an underutilized animal-origin precursor, pig hair, to be used as supercapacitor electrodes.

The study focused on pig hair, an abundant waste product of the meat industry, which is rich in dietary keratin protein. The production of activated carbonActivated carbon is a form of carbon that has been processed to create a vast network of tiny pores, increasing its surface area significantly. This extensive surface area makes activated carbon exceptionally effective at trapping and holding impurities, like a molecular sponge. It is commonly More involved a two-step process: initial pre-carbonization at various temperatures (350, 400, 450, and 500∘C), followed by chemical activation at 800∘C using potassium hydroxide (KOH). This is the first published study to systematically examine the effect of pre-carbonization temperature on the properties of activated carbon derived from animal-origin precursors for supercapacitor applications, filling a significant research gap.

The pre-carbonization temperature was found to be the pivotal factor determining the resulting material’s structural and electrochemical properties. Characterization using scanning electron microscopy (SEM) and nitrogen physisorption analysis showed a clear trend: higher pre-carbonization temperatures promoted better pore development and larger specific surface areas. The sample pre-carbonized at 500∘C (PH 500-800) exhibited a highly porous and rough surface, which correlated with the highest measured Brunauer-Emmett-Teller (BET) specific surface area of 1002 m2/g. In contrast, the lowest temperature sample ( PH 350-800) only achieved 117 m2/g. Furthermore, Raman analysis suggested that higher pre-carbonization temperatures produced more structurally ordered amorphous carbon.

Electrochemical testing via cyclic voltammetry (CV) confirmed that the structural improvements directly translated to enhanced energy storage performance. The materials primarily stored energy through electric double-layer (EDL) capacitance, a physical process dependent on the separation of charge at the electrode-electrolyte interface, which is favored by high surface area and accessible pores. The specific capacitance values followed a direct proportionality with the pre-carbonization temperature and surface area. At the lowest scan rate (5 mV/s), the specific capacitance descended in the order: PH 500-800 (110 F/g), PH 450-800 (84 F/g), PH 400-800 (80 F/g), and PH 350-800 (41 F/g).

Although the primary contribution to charge storage was the EDL mechanism, the presence of surface oxygen detected by EDX also contributed significantly to faradaic (charge transfer) processes, a synergistic effect that further enhanced the total energy storage capacity. Impedance analysis further validated the results, showing that the PH 500-800 material had a characteristic discharge time of only 15.6 s, indicating its high-power capability, which was significantly better than the 45.5 s for the PH 350-800 sample. This consistent trend across multiple tests strongly reaffirms the critical role of the pre-carbonization step in developing high-performance activated carbons from an animal-origin precursor. The study successfully demonstrates that optimizing pre-carbonization conditions is a viable strategy for designing sustainable, high-power materials for next-generation supercapacitor technology.

Source: Lobato-Peralta, D.R., Okolie, J.A., Orugba, H.O., Arias, D.M., Sebastian, P.J., & Okoye, P.U. (2025). Evaluating the impact of pre-carbonization on activated carbon production from animal-origin precursors for supercapacitor electrode applications. Biomass and Bioenergy, 193, 107574.