Recent Breakthroughs in Supercapacitors Boosted by Nitrogen-Rich Porous Carbon Materials

Featured with unique mechanical, electronic and chemical properties, nitrogen-doped carbon materials have become the research hotspot of energy storage. As electrode materials in supercapacitors (SCs), N-doped carbons have demonstrated intriguing flexibility and superb performances in a wide electrochemical window, equipped with versatile properties as both cathodes and anodes for constructing high voltage devices. Compared with limited doping level, N-rich and porous carbon materials (NPCs) are of great desire to release the restricted properties of N species and obtain high specific capacitances (>600 F g^-1), pushing the energy density towards the battery level without scarifying the capacitor-level power ability. In this Research News we firstly discuss the key factors influencing the performance of NPC electrodes to disclose related charge storage mechanisms. In addition, the trade-off among N-content, porous structure and electrical conductivity is involved as well as electrochemical behaviors in different electrolytes. Also, various progressive developments are highlighted systematically ranging from asymmetric to symmetric and hybrid configurations, covering both aqueous and non-aqueous systems. Finally, some stubborn and unsolved problems are summarized, with prospective research guidelines on NPC-based SCs.