Biomass-derived porous carbons are increasingly examined as practical electrode materials for supercapacitors because they combine low cost with adaptable structural features. In this study, black-eyed pea peels, a widely available agricultural residue, is used as the precursor and activated with either K2CO3 or KMnO4, which resulted in noticeable differences in pore development and electrochemical behaviour. Thermogravimetric analysis showed that the derived carbons retain good thermal stability. X-ray diffraction, X-ray photoelectron spectroscopy, and Raman measurements indicated a largely disordered carbon framework with only limited graphitic domains, offering numerous defect sites that support ion adsorption. Scanning electron microscopy revealed thin carbon walls and an ultra-microporous network with a considerable proportion of mesopores, which was further supported by Brunauer–Emmett–Teller analysis. The material obtained using K2CO3 delivered a capacitance of around 236 F g− 1, sustained almost 99% of its performance during long cycling, and responded better at high current. The KMnO4 activated sample exhibited additional pseudocapacitive contributions but lower stability. Overall, these results underline the role of activation chemistry in governing pore architecture and surface functionality and show that agricultural residues can be transformed into viable electrode materials for high-power energy-storage applications.

Thin-walled porous carbon from black-eyed pea peels: a green route toward high-power supercapacitors
    Abstract
    1 Introduction
    2 Experimental
        2.1 Materials
        2.2 Characterization techniques
        2.3 Preparation of activated carbon from black-eyed pea peels
        2.4 Electrochemical measurements
    3 Results and discussions
        3.1 Thermogravimetric analysis
        3.2 XRD data analysis
        3.3 FTIR data analysis
        3.4 Raman data analysis
        3.5 Scanning electron microscopy (SEM) analysis
        3.6 BET analysis
        3.7 XPS analysis
        3.8 CV analysis
        3.9 GCD analysis
        3.10 EIS analysis
    4 Conclusion
    References

• Reddi Mohan Naidu Kalla(Department of Fiber System Engineering, Yeungnam University, Gyeongsan 38541, Republic of Korea)
• Jaewoong Lee(Department of Fiber System Engineering, Yeungnam University, Gyeongsan 38541, Republic of Korea) Corresponding author
• Rajesh Cheruku(Department of Physics, School of Engineering, Dayananda Sagar University, Harohalli, Bengaluru 562112, Karnataka, India)
• Sivarama Krishna Lakkaboyana(Department of Chemistry, Vel Tech Rangarajan Dr. Sagunthala R&D Institute of Science and Technology, Chennai 600062, Tamil Nadu, India) Corresponding author
• Sreedhar Doraswamy(R&D-Materials, Amara Raja Energy & Mobility Limited, Tirupati 517520, India)