In this study, activated biochar was produced using pilot-scale technologies of fast pyrolysis and activation to create desirable morphology, surface chemistry, and adsorptive properties for application in supercapacitors. First, residues from white birch were converted into biochar by fast pyrolysis (~ 450 °C). Then, physical (using CO₂) or chemical (using KOH) activation was carried out in a homemade pilot-scale furnace at 900 °C. These synthesized materials presented distinct porosity structures: micro-/mesoporous (CO₂ material) and highly microporous (KOH material), reaching surface areas of up to 1700 m² g⁻¹. Electrochemical results showed that KOH-activated biochar had higher specific electrical capacitance in both acidic and neutral electrolytes with a maximum specific capacitance value of 350 and 118 F g⁻¹ at 1 A g⁻¹, respectively; while, for CO₂-activated biochar, the maximum obtained values were 204 and 14 F g⁻¹. The greater proportion of oxygenated and nitrogenated functional groups on the surface of the KOH activated biochar, along with its high surface area (with wider porosity), improved its performance as a supercapacitor electrode. Specifically, the low proportion of ultramicropores was determinant for its better electrochemical behavior, especially in the neutral electrolyte. Indeed, these results are similar to those found in the literature on the electrical capacitance of carbonaceous materials synthesized in a small-scale furnace. Thus, the chemical-activated biochar made from wood residues in pilot-scale furnaces is a promising material for use as electrodes for supercapacitors.

在这项研究中，使用快速热解和活化的中试规模技术生产活化的生物炭，以产生所需的形态，表面化学和吸附性能，以用于超级电容器。首先，白桦的残留物通过快速热解（约450°C）转化为生物炭。然后，在自制的中试炉中在900°C下进行物理（使用CO ₂）或化学（使用KOH）活化。这些合成的材料呈现出独特的孔隙结构：微/中孔（CO ₂材料）和高度微孔（KOH材料），表面积达到1700 m ²  g ^-1。电化学结果表明，KOH活化的生物炭在酸性和中性电解质中均具有较高的比电容，在1 A g ^-1处的最大比电容值分别为350和118 F g ^-1。而对于CO ₂活化的生物炭，最大获得值为204和14 F g ^-1。KOH活化的生物炭表面上较大比例的氧化和氮化功能基团，以及其高表面积（具有更大的孔隙率），改善了其作为超级电容器电极的性能。特别地，低比例的超微孔是决定其更好的电化学性能的决定因素，尤其是在中性电解质中。实际上，这些结果与在小型炉中合成的含碳材料的电容的文献中发现的结果相似。因此，在中试炉中由木材残留物制成的化学活化生物炭是一种有前途的材料，可用作超级电容器的电极。