Preparation of Fe-doped hypercrosslinked poly(naphthalene-based) microporous carbon and its electrochemical properties

Abstract

Supercapacitors, as an eco-friendly energy storage system, have garnered significant interest due to distinct charging/discharging mechanisms, superior power density, and robust cycle stability. This study introduces a novel approach to enhance the typically low energy density of carbon materials. By employing ferrocene (Fc) as a dopant and utilizing an external crosslinker technique for “knitting”, we synthesized Fe-doped hypercrosslinked poly(naphthalene-based) polymer MON-Fe. This polymer served as a precursor for generating Fe-doped microporous carbon, termed MONC-Fe-800–1, through a chemical activation process. Comparing the structural features of MON-Fe and MONC-Fe-800–1, microporous carbon MONC-Fe-800–1 has a more pronounced hierarchical pore structure with higher microporosity (accounting for 81.43 % of its structure) and specific surface area (819.42 m2g−1). In a 6 M KOH electrolyte, the specific capacity of MONC-Fe-800–1 was observed to be 264.8 C g−1 at a current density of 1.0 A g−1, which is much higher than the specific capacity of MON-Fe (131.9 C g−1). A MONC-Fe-800–1//MONC-800–2 hybrid supercapacitor (HSC) device was constructed with an energy density of 15.2 Wh kg−1 at a power density of 750.0 W kg−1. Notably, after 5000 charge-discharge cycles at 1.0 A g−1, the device maintained 83.16 % of its initial capacity with 99.92 % coulombic efficiency, which compares with 63.87 % capacity retention and 84.00 % coulombic efficiency obtained by MON-Fe//MONC-800–2 HSC, highlighting the Fe-doped microporous carbon's enhanced electrode material potential compared to its precursor.