Energy storage for sustainable development and progress of power production industries is vitally important. The energy storage devices are under extensive research from last three decades to ensure the hand-on-hand coordination with power supply phenomenon and to reduce the energy loses in lines. The cost-effective materials are still highly demanding as an electrode material for energy storage devices. Biomass-derived carbon materials are best candidates due to their low cost, relatively high abundance, pollution-free nature. Here, we are reporting a facile two-step green approach to convert Himalayan horse chestnuts (HHCNs) into activated carbon materials. In first step, grinding and pyrolysis of the HHCNs were carried out, and then activation was performed using KOH to enhance the pore density and surface area. HHCNs-derived carbon was utilized as an electrode in electrical double-layer capacitors (EDLCs) with 1 M H2SO4 as an electrolyte. The macroporous structure along with hierarchical porous network acts as an efficient source of transportation of charges across the electrode and separator. Cyclic voltammetry test was taken from 10 to 100 mV/s current and within a range of 0–1 V applied potential; approximately rectangular CV shown mirror response towards current and shown typical EDLCs properties. The proximate analysis confirms the presence of heteroatoms like sulfur, oxygen, and nitrogen which act as carbon dopants. The wettability of HHCNs-derived carbon enhanced due to the various types of oxygen functionalities inherited from the lignin skeletal part. The nitrogen content is primarily responsible for the pseudo-capacitive behavior of HHCNs-codoped carbon. HHCNs-derived activated carbon materials has emerged as a promising electrode material for energy storage applications.

Aesculus indica-derived heteroatom-doped carbon as an electrode material for super-capacitor
    Abstract
        Graphical abstract
    1 Introduction
    2 Materials and methods
        2.1 Materials acquired
        2.2 Synthesis of codoped carbon from HHCN biomass
    3 Characterizations
    4 Results and discussion
        4.1 XRD and Raman
        4.2 Morphology of HHCNs-derived carbons
        4.3 Pore size distribution and BET area of HHCNs
    5 Electrochemical applications
    6 Conclusion
    References

• Fakhar Zaman(Beijing Key Laboratory of Electrochemical Process and Technology for Materials, Beijing University of Chemical Technology, Beijing 100029, People’s Republic of China)
• Muhammad Waqas Ishaq(Department of Chemistry, The University of Texas at Austin, Austin, TX 78712, USA)
• Aisha Munawar(Department of Chemistry, Faculty of Natural Sciences, University of Engineering and Technology Lahore, Lahore 54890, Pakistan)
• Umer Younas(Department of Chemistry, The University of Lahore, 1‑kilometer from Defense Road, Lahore 54590, Pakistan)
• Zahid Ali(Department of Chemistry, The University of Lahore, 1‑kilometer from Defense Road, Lahore 54590, Pakistan, State Key Laboratory of Organic‑Inorganic Composites, Beijing University of Chemical and Technology, Beijing 100029, People’s Republic of China)