Bamboo-like tubular nitrogen-doped carbon derived from g-C3N4 as an ultra-high performance anode of potassium-ion battery

[Display omitted] •Bamboo-like carbon nanotubes prepared from g-C3N4 catalyzed by transition metal salts.•Excellent electrochemical performance of CNC anode studied.•CNC possesses ultrahigh storage capacity (353.9 mA h g−1) for PIBs. Carbon materials are still the most widely studied anode materials for potassium ion batteries (PIBs) attributed to their advantages of wide source, controllability, and environmental friendliness. In this paper, a bamboo-like tubular nitrogen-doped carbon material (CNC) was prepared by using g-C3N4 as the precursor and transition metal salt as the catalyst and template. CNC has the advantages of a bamboo-like tubular structure, rich nitrogen content, and large layer spacing. As anode of PIBs, CNC can deliver an impressive initial reversible capacity of 488.6 mAh/g at 0.1 A/g. At a high current density of 1 A/g, CNC still retains a reversible capacity of 291 mAh/g after 1000 cycles. The excellent performance of CNC anode can be due to the porous bamboo-like tubular structure that promotes K ions diffusion and the rich nitrogen content that provides abundant active sites for K ions.