Regulating potassium ion receptivity by structure engineering in constructing carbon nano-network with optimized nitrogen species

Structure engineering and composition regulation of carbon-based materials have become a promising strategy for dealing with the depressed kinetics and inferior structure stability in accommodating K+ ion process. Herein, the component-optimal disordered carbon with “Ice- Cube” architecture (C-Z@RF) has been conducted by a facile pyrolysis process of modified ZIF8. The electrochemical reaction kinetics has been boosted by the abundant active sites derived from the introduction of numerous pyridinic-N and the design of hierarchical framework, and the structure integrity is well maintained during repeated K+ insertion/de-insertion process by employing the hollow architecture to restrain the stress concentration. As expected, benefitting from the synergistic effect of structure design and component control, the C-Z@RF electrode materials present a superhigh reversible capacity of 109.8 mA h g-1 at 10.0 A g-1 after 4000 cycles and even can still maintain 119.2 mA h g-1 at the enlarged current density of 20.0 A g-1. Above all, the investigation in this work has provided a promising perspective to exploit carbonaceous material with prominent high-rate performance and long-term lifespan for advanced PIBs.