Fabrication of Fe3C nanoparticles embedded in N-doped carbon nanotubes/porous carbon 3D materials derived from distilled grains for high performance of potassium ion battery

Abstract

The design and fabrication of advanced carbon materials is highly important for potassium ion batteries. In this paper, Fe 3 C nanoparticles embedded in N-doped carbon nanotubes/porous carbon (Fe 3 C@N-CNPC) 3D materials were synthesized by pyrolysis of N-doped distilled grains in the presence of FeCl 3 /ZnCl 2 activators. It was demonstrated that the FeCl 3 /ZnCl 2 activators played an important role in the formation of Fe 3 C@N-CNPC 3D materials. On the one hand, the activator endowed the carbonaceous materials with a high proportion of micropores and large surface area. On the other hand, Fe nanoparticles generated by decomposition of FeCl 3 catalyzed the growth of intertwined carbon nanotubes on porous carbon, yielding Fe 3 C@N-CNPC 3D materials with abundant porous structure and a high degree of graphitization. The as-prepared Fe 3 C@N-CNPC were used as anode materials for potassium ion batteries. Due to the synergistic effect of N-doping, superstructure, and large surface area, the Fe 3 C@N-CNPC based potassium ion batteries exhibited remarkable potassium storage capacity (273 mAh g −1 at 100 mA g −1 ) and excellent cycle stability (94% capacity retention at 100 mA g −1 after 570 cycles). This novel carbon material with low cost and ease preparation is of great significance for the application of potassium ion batteries. Meanwhile, our strategy also provides a reference idea for the resource utilization of the distilled grains waste. • N-doped carbon nanotubes/porous carbons were prepared by nitrogen doping and chemical catalysis processes. • The presence of the activator ferric chloride determines the formation of carbon nanotubes. • The carbon nanotubes effectively increase the specific surface area and graphitization degree of the material. • The N-doped carbon nanotubes/porous carbon provides support for the fast transport and stable storage of potassium ions.