The creation of extra storage capacity in nitrogen-doped porous carbon as high-stable potassium-ion battery anodes

Porous carbonaceous materials have been extensively explored as promising anodes for potassium-ion batteries (KIBs), and their potassium storage capacities are always higher than the theoretical specific capacity (279 mA h g(-1)). However, the mechanism behind the extra capacity for KIBs in porous carbonaceous materials is rarely explored. Herein, we synthesized porous carbonaceous materials with interconnected nanopores modified by abundant edge-doped N atoms to investigate the mechanism for potassium-storage performance. The resulting NPCs-600 displays outstanding electrochemical performances with a high reversible capacity (409 mA h g(-1) at 0.1 A g(-1) after 200 cycles), excellent rate capability (235 mA h g(-1) at 5 A g(-1)), and remarkable long-term cycling stability (167 mA h g(-1) at 5 A g(-1) after 10,000 cycles). The remarkable performance results from the nanopores grafted by edge-doped nitrogen atoms on the inner surface which can adsorb more K+ to enhance the capacity of carbon materials beyond K+ intercalation mechanism. Furthermore, the density functional theory (DFT) calculations further demonstrate that nitrogen atoms doped on the edge of defects facilitate to the sorption of K+, providing the extra capacity for KIBs. (C) 2021 Elsevier Ltd. All rights reserved.

Automated summary

The porous carbonaceous materials with interconnected nanopores modified by abundant edge-doped nitrogen atoms exhibit outstanding potassium-storage performance, achieving high reversible capacity, excellent rate capability, and remarkable long-term cycling stability. The presence of nitrogen atoms doped on the edge of defects facilitates the sorption of potassium ions, providing extra capacity for potassium-ion batteries.