Interfacial growth of N,S-codoped mesoporous carbon onto biomass-derived carbon for superior potassium-ion storage

Carbonaceous materials have been recognized as one of the most promising anode materials for potassium-ion batteries (PIBs) due to their abundant raw materials, controllable structure, superior conductivity, and good chemical inertness. However, the large radius of K ions and the low potassium content of intercalation compounds result in the sluggish storage kinetics and low reversible capacity of carbon anodes. In this work, we present a unique heteroatom-doped carbon composite (denoted as NS-MC/SC) through a facile interfacial assembly route and simple heat-treatment process, where NS-MC is well grafted onto the biomass-derived spore carbon (SC). This unique structural design endows it with abundant mesoporous channels, expanded layer spacing, and highly doped N and S. With these merits, the NS-MC/SC anode in PIBs exhibits a high reversible capacity of 350.4 mAhg−1 at 100 mAg−1 after 300 cycles, and an outstanding cycling stability. Besides, in-situ Raman spectra further verify the high reversibility of K ions insertion/extraction. Importantly, theoretical simulations also reveal that the N,S dual-doping is an efficient approach for improving the potassium-ion storage performance of NS-MC/SC.