Activation effects on rapeseed stalk-derived biochar for supercapacitor electrodes

Yılmaz A., Coşkuner A. B., PARLAK K., GEYİKÇİ U., TOPARLI Ç., Özbek N., ...Daha Fazla

Journal of Power Sources, cilt.693, 2026 (SCI-Expanded, Scopus)

  • Yayın Türü: Makale / Tam Makale
  • Cilt numarası: 693
  • Basım Tarihi: 2026
  • Doi Numarası: 10.1016/j.jpowsour.2026.241161
  • Dergi Adı: Journal of Power Sources
  • Derginin Tarandığı İndeksler: Science Citation Index Expanded (SCI-EXPANDED), Scopus, Chemical Abstracts Core, Chimica, Compendex, INSPEC, Academic Search Ultimate (EBSCO), Engineering Source (EBSCO)
  • Anahtar Kelimeler: Biochar, Chemical activation, Hierarchical porous carbon, Rapeseed stalk, Supercapacitor
  • Orta Doğu Teknik Üniversitesi Adresli: Evet

Özet

Agricultural residues are promising sustainable precursors for functional carbon materials in energy storage applications. In this study, activated biochars were prepared from rapeseed stalk (RS) using KOH, LiCl, and ZnCl2/FeCl3, and the effects of different activation strategies on their structural properties and electrochemical performance were systematically investigated. Among the prepared materials, the KOH-activated biochar (RSC-K) exhibited a micropore-rich structure with a high specific surface area of 1415.1 m2 g−1 and partial graphitic ordering. In a three-electrode configuration, the RSC-K electrode delivered a specific capacitance of 314.3 F g−1 at 0.1 A g−1 with a low charge-transfer resistance (1.02 Ω), despite a relatively high equivalent series resistance (0.81 Ω), and retained 96% of its initial capacitance after 7,000 cycles at 5 A g−1. In contrast, the LiCl- and ZnCl2/FeCl3-activated biochars exhibited lower surface areas and inferior electrochemical performance. A symmetric two-electrode supercapacitor assembled using RSC-K delivered a specific capacitance of 95.0 F g−1 at 1 A g−1, retained 71.1% of its initial capacitance after 10,000 cycles, and achieved a maximum energy density of 3.1 Wh kg−1 at a power density of 243.8 W kg−1. These results demonstrate the effectiveness of KOH activation for producing sustainable biochar electrodes for supercapacitor applications.