Nitrogen/phosphorus co-doped carbon decorated with metallic zinc for high-performance potassium-ion batteries

Carbonaceous anodes of potassium-ion batteries (PIBs) hold sluggish adsorption and diffusion kinetics due to the large radius of K+, leading to poor cyclic stability and low specific capacity. Herein, an amorphous carbon material composed of N/P-doped active sites and trace amount of metallic zinc (Zn-NPC) is prepared through a facile self-sacrificing template method. Both experimental data and theoretical calculations indicate the co-doping of metallic zinc, and N/P atoms contribute to the low charge transfer impedance, high electronic conductivity, significant adsorption behavior, and remarkable diffusion kinetics of K+ ions. As a result, Zn-NPC anode delivers high capacity of 300.1 mA h g−1 at 50 mA g−1, and superior cycle performance with a reversible capacity of 196.1 mA h g−1 after 1400 cycles at 200 mA g−1. This work will open window for the doping strategy of carbon material and facilitate the practical application of PIBs in the energy storage field.