Phosphorus-Regulated Nitrogen Sites in Ultrathin Carbon Scrolls for Stable Potassium Storage

ABSTRACT: Carbonaceous materials are promising potassiumion battery (PIB) anodes because of their merits of low cost and potentially porous structure. Unfortunately, sluggish kinetics of carbonaceous materials with limited active sites result in unsatisfactory cycling stability and poor rate performance. Herein, high active nitrogen sites are regulated through the additional phosphorus doping in 2D nitrogen-rich porous ultrathin carbon scrolls (P-N/UCS), realizing stable and high-rate potassium storage. Moreover, the P-N/UCS anode affords expanded interlayer distance and enhanced conductive networks with abundant pore structures and defects, which further accelerate charge transfer and K+ diffusion kinetics. Meanwhile, the P-N/ UCS anode reveals a large specific surface area and high active N sites, which can expose additional open active sites to boost interfacial K+ adsorption reactions. Theoretical calculations further certify that the P-N/UCS anode can effectively enhance the adsorption capability of K+; thus, potassium storage performance is promoted. As a proof of concept, the as-prepared P-N/UCS anode exhibits a high specific capacity of 382.8 mAh g-1 after 500 cycles at 0.1 A g-1 and long cycle stability of 265.8 mAh g-1 after 2000 cycles at 1.0 A g-1. This work paves an avenue for the further controllable large-scale exploration of high-performance potassium storage anodes.