Nitrogen-Doped Nanoporous Graphenic Carbon: An Efficient Conducting Support for O2 Cathode

• Published in: ChemNanoMat : chemistry of nanomaterials for energy, biology and more biology and more, 2016-07, Vol.2 (7), p.692-697
• Main Authors: Xing, Zhenyu, Luo, Xiangyi, Qi, Yitong, Stickle, William F., Amine, Khalil, Lu, Jun, Ji, Xiulei
• Format: Article
• Language: English
• Subjects: composite carbon; graphenic; Li-O2 battery; N-doping; nanoporous carbon
• ISSN: 2199-692X; 2199-692X
• DOI: 10.1002/cnma.201600112

Herein, we synthesize a nanoporous N‐doped graphenic carbon with high surface area and a higher graphenization/graphitic degree by further developing the metallothermic reduction of gaseous CO2 by adding N2 into the gas flow. The N‐doped nanoporous carbon is composed of both a highly porous graphenic and non‐graphitic matrix and homogeneously dispersed ordered graphitic nanodomains, which constitute a very unique composite carbon structure. The resulting N‐doped graphenic carbon exhibits much more favorable reactivity as a carbon conducting support in the O2 cathode of Li‐O2 batteries, increasing the specific capacity of the GC electrode from 5300 to 9600 mAh g−1. The N‐doped carbon also exhibits lower overpotentials during initial cycling for the charging process as well as an enhanced cycling performance compared to the undoped carbon. These results demonstrate that N‐doping has a strong correlation with the enhanced performance of O2 cathode of Li‐O2 batteries. N‐doped nanoporous carbon with enhanced graphenization and graphitization degrees has been prepared by using N2 gas as a N‐doping agent in a metallothermic reduction of gaseous CO2. By comparing two carbons, N‐doped and non‐doped, both formed by the metallothermic reactions, the results unambiguously demonstrate that N‐doping has a strong correlation with the enhanced performance of O2 cathode of Li‐O2 batteries.