Flash-assisted doping graphene for ultrafast potassium transport

Graphene has been widely used for electrical energy storage and its performances could be further improved by heteroatom doping. How to prepare doped graphene efficiently and economically remains a significant challenge. Here, we propose a flash-assisted doping method to produce nitrogen- and sulfur-doped graphene (N-rGO and S-rGO). Using this method, graphene oxide (GO) is reduced to few-layer graphene (rGO) in seconds without the use of reductants, accompanied with a high doping efficiency. Particularly, the as-synthesized N-rGO with a high N content of 12.75 at.% used as potassium-ion battery (KIB) anode exhibits ultrafast K⁺-transport kinetics and superior K⁺-storage capability. Quantitative kinetics analysis and theoretical simulation are used to reveal the mechanism of transportation and storage of K⁺ in N-rGO.