Nitrogen, Phosphorus Co-doped Carbon Obtained from Amino Acid Based Resin Xerogel as Efficient Electrode for Supercapacitor

The organic xerogel was synthesized from the polymerization reaction of a kind of amino acid, tyrosine, and pyrrole-2-carbaldehyde using phosphoric acid as the catalyst and phosphorus source. Nitrogen (N) and phosphorus (P) co-doped carbon (NPC) aerogels were obtained via the cabonization of the synthesized organic xerogel and subsequently being activated by KOH. The influences of the activation agent ratio and activation temperature on the structure, morphology, and the final electrochemical property of NPC materials have been investigated. Compared to the nonactivated sample, the obtained activated N/P-co-doped hierarchical porous carbon exhibits superior electrochemical performance. The optimized sample shows a high specific capacitance of 302 F g–1 at 0.5 A g–1 and good rate capability with capacitance remaining of 214 F g–1 at 20 A g–1, as well as excellent cycling stability with 100% retention after 20,000 cycles in 6 M KOH electrolyte. Considering the practical application, when 60 mg of active material is loaded, the mass specific capacitance of the prepared high mass loading electrode can reach to 240 F g–1 at 0.5 A g–1, and the maximum area capacitance is up to 14.4 F cm–2. Furthermore, the constructed symmetric supercapacitor displays a remarkable maximum energy density of 21.5 W h kg–1 at a power density of 250 W kg–1 and ultralong cycling life with no attenuation in the specific acpacitance even after 100,000 cycles.