Template induced self-oxidative polymerization of phenols to mesoporous carbon doped with faradaic active oxygen for high-performance supercapacitor

Facile synthesis of nanocarbons with rich faradaic-active functionalities is urgently needed for supercapacitor in aqueous electrolytes to address the bottleneck of low energy density (usually below 10 Wh/kg). Herein, we report a template induced self-oxidative polymerization method for the fabrication of nanocarbon with commercial Mg(OH)(2) as template to absorb phenol (catechol or phloroglucinol) via acid-base interaction. The absorbed phenol undergoes self-oxidative polymerization to form a composite of polyphenol and template. The resultant flower-like material with open access morphology display large surface area (1303 m(2)/g), rich mesoporosity (over 80%), and rich faradaic oxygen functionalities (7.4 atom%) in the forms of -C = O and -C-O-groups. Benefiting from these features, the phloroglucinol derived product (PMC973) exhibits excellent supercapacitor performances in aqueous electrolyte including ultrahigh energy density of 36.7 Wh/kg (at 1000 W/kg), maintaining energy density of 22.9 Wh/kg at 18 800 W/kg, superior capacitance retention of over 70% and excellent cycling stability with 97.8% capacity retention after 10 000 charge/discharge cycles, offering huge potential for energy storage. The developed strategy avoids the use of harmful formaldehyde as linker reagent, thus providing a green and simple approach for the fabrication of functional nanocarbons that are applicable in a large numbers of fields.