Dense N-doped carbon nanotubes with encapsulated Fe nanoparticles directly grown within red brick as a sustainable monolithic electrode for high-performance supercapacitors

A monolithic electrode is developed by growing dense N-doped carbon nanotubes (NCNTs) embedded with Fe nanoparticles within a red brick substrate (Fe@NCNTs/RB) for supercapacitors with high areal capacitance, energy density, and cycling stability.