Cost-effective and sustainable high-performance supercapacitor material was successfully prepared from cellulosic waste (Sapindus trifoliatus nut shells) biomass-derived activated carbon (CBAC) by physical activation method. The CBAC displays nanofiber morphology, high specific surface area (786 m2/ g), large pore volume (0.212 cm3 g− 1) which are evaluated using FESEM, BET and possessed excellent electrochemical behavior analyzed through various electrochemical methods. Moreover, the assembled symmetric CBAC//CBAC device exhibits high specific capacitance of 240.8 F g− 1 with current density of 0.2 A g− 1 and it is maintained to 65.6 F g− 1 at high current density of 2.0 A g− 1. In addition, the symmetric device delivers an excellent specific energy maximum of over 30 Wh kg− 1 at 400 W kg− 1 of specific power and excellent cycling stability in long term over 5000 cycles. The operation of the device was tested by light-emitting diode. Hence, CBAC-based materials pave way for developing large-scale, low-cost materials for energy storage device applications.

    Abstract
    1 Introduction
    2 Experimental
        2.1 Preparation of biomass-derived porous activated carbon nanofibers
        2.2 Physical characterization
        2.3 Electrochemical characterization
    3 Results and discussion
    4 Conclusions
    Acknowledgements 
    References

• Murugan Vinayagam(Chemical Engineering Area, CSIR-Central Leather Research Institute and University of Madras)
• Rajendran Suresh Babu(Laboratory of Experimental and Applied Physics, Centro Federal de Educação Tecnológica, Celso Suckow da Fonseca (CEFET/RJ))
• Arumugam Sivasamy(Chemical Engineering Area, CSIR-Central Leather Research Institute and University of Madras)
• Ana Lucia Ferreira de Barros(Laboratory of Experimental and Applied Physics, Centro Federal de Educação Tecnológica, Celso Suckow da Fonseca (CEFET/RJ))