Reactive Template and Confined Self-Activation Strategy: Three-Dimensional Interconnected Hierarchically Porous N/O-Doped Carbon Foam for Enhanced Supercapacitors

Abstract

Herein, we report a new reactive template and confined self-activation strategy for the preparation of three-dimensional interconnected hierarchically porous N/O-doped carbon foam (3DHPNCF), which contains abundant micropores, mesopores, and macropores via using mesoporous silica SBA-15 as a hard template and ethylenediaminetetraacetic acid tripotassium (EDTA-3K) as a single carbon/nitrogen precursor, respectively. Importantly, potassium carbonate produced by the pyrolysis of EDTA-3K can effectively react with the SBA-15 silica skeleton to form water-soluble potassium silicate, after hot-water removal, leading to a continuous macropore structure. Simultaneously, a confined alkali activation reaction is carried out between potassium carbonate and in situ as-formed carbon to create meso/micropores. 3DHPNCF exhibits the high specific surface area and pore volume, as well as rich content of in situ-doped oxygen/nitrogen element, contributing to the high specific capacitance, good rate capability, and outstanding cycling stability. We provide a novel, green, and universal strategy for the design and fabrication of novel hierarchically porous carbons