Oxygenated N-doped porous carbon derived from ammonium alginate: Facile synthesis and superior electrochemical performance for supercapacitor

Fabrication of oxygenated N-doped porous carbon is an important way for performance improvement and application expansion of carbon materials. It is still a great challenge to synthesize oxygenated N-doped porous carbon from alginate salts via a simple and low-cost method, because most methods for the preparation of alginate-derived porous carbon need chemical activation agents and acid washing. In this work, oxygenated N-doped porous carbon with high surface area was successfully prepared through carbonization of ammonium alginate aerogel followed by air activation treatment. During the preparation of porous carbon, only the greenest water is used as the solvent, and its volume significantly influences the porous structure of the carbonization product, which can be further modified by air activation treatment. The obtained porous carbon exhibits excellent electrochemical performance when used as electrode materials for supercapacitors, e.g. high specific capacitance (204 F g−1 at 1 A g−1 in two-electrode system), good rate capability and ultralong cycle life (91.2% capacitance retention after 10,000 charge/discharge cycles) due to its rich porous structures and heteroatom doping. This work may be further extrapolated to benefit other applications of alginate-derived carbon and may open up a new avenue to fabricate heteroatom doped porous carbon.