Nitrogen-doped hierarchical porous carbon with ultrathin graphitic framework for superior lithium storage

Abstract

The fabrication of nanocarbons possessing ultrathin graphitic structure and ultrahigh nitrogen doping simultaneously remains challenging so far. Herein, we develop a novel and versatile strategy to prepare ultrahigh nitrogen-doped hierarchical porous carbon with ultrathin graphitic framework (NHPCs), through the Schiff-base reaction of melamine and terephthalaldehyde in the presence of lithium oxide, as high-performance anodes for rechargeable lithium ion batteries. During one-pot solid-phase interface reaction, Li2O was used to absorb the in-situ generating H2O enhancing the formation of Schiff-based networks and LiOH was in-situ obtained, which can be used as active agent to increase the BET surface areas of final carbons. The obtained NHPCs present 3D hierarchical honeycomb-like morphology, ultrahigh nitrogen content up to 12.2 wt%, large specific surface area of 1260 m2 g−1. These unique structural properties allowed for fast ion diffusion and rapid electron transport, and offered enriched active sites for lithium storage. NHPCs presented a high reversible capacity of 880 mAh g−1 at 100 mA g−1 even after 100 cycles, and exceptional rate capability with 301 mAh g−1 at 3000 mA g−1, outperforming most reported nano‑carbons. Therefore, this strategy will open a new way to prepare heteroatom-doped porous carbons with a controllable hierarchical structure, for high-performance energy storage.