Atomically Dispersed Co Anchored into Highly Nitrogen-Doped One-Dimensional Mesoporous Carbon with Large Pore Size for Ultra-Stable Potassium-Ion Storage

Mesoporous carbon materials have emerged as promising candidates for potassium-ion batteries (PIBs) as anode materials due to their tunable pore structure, excellent conductivity, and high surface area. However, the sluggish reaction kinetics caused by the larger radius of K ions results in poor potassium storage performance. Here, we report a facile tetraethyl orthosilicate-mediated co-assembly strategy for anchoring cobalt single atoms into highly nitrogen-doped mesoporous carbon/carbon nanotubes (Co-NMC@CNTs). The resulting composite features large mesopore size of approximately 23.7 nm, robust 1D structure, and abundant active sites introduced by Co single atoms and a high nitrogen doping of 13.6 at.%. Synchrotron radiation analysis and theoretical simulation further demonstrate that the presence of Co single atoms significantly reduces diffusion barriers of K ions and increases energy storage centers. When used as PIB anodes, the newly designed Co-NMC@CNTs electrode demonstrates an exceptional electrochemical performance with a high reversible capacity of 362.3 mAh g⁻¹ at 100 mA g⁻¹ after 300 cycles and an outstanding cycling stability with a capacity of 192.0 mAh g⁻¹ at 1000 mA g⁻¹ after 4000 cycles. This work opens up a new blueprint for achieving high-performance mesoporous carbon-based electrodes in next-generation energy storage applications.