Construction of mesoporous carbon sphere with local short-range ordered graphitized structure for high-rate potassium storage

Mesoporous carbon spheres (MCSs) have emerged as promising high-performance anodes of potassium ion batteries (PIBs) due to their larger layer spacing, randomly distributed amorphous regions, and abundance of defect sites. However, achieving high potassium-storage capacity at high current densities remains a difficult challenge due to its highly disordered structure leading to low conductivity. Herein, we propose a novel synthetic strategy to introduce locally short-range ordered graphitized structure into mesoporous carbon spheres to tunning the morphology and the internal structure, which improves the electrical conductivity , increases the specific surface area, and enriches K + intercalation sites. The optimized locally graphitized mesoporous carbon spheres (LGMCSs-2) exhibit a high-rate performance (210.1 mAh g −1 ) at 5 A g −1 and delivers a capacity of 214.2 mAh g −1 at 1 A g −1 after 500 cycles. Even after 1000 cycles at 5 A g −1 , it can still maintain a capacity of 144.3 mAh g −1 . The superior rate capability and excellent cycling stability of LGMCSs-2 electrode are attributed to the well-defined mesoporous structure and locally graphitized structure design, which enhance the potassium-ion reaction kinetics. This work provides a new approach to designing local short-range ordered MCSs and offers valuable insights into the carbon-based anodes with fast charge/discharge capability for PIBs. The morphologies of the mesoporous carbon spheres were changed by the addition of transition metal catalysts, which introduced the locally graphitized structure and increased the pore size. The unique structure synergistically enhances both the K + insertion and adsorption capacity, achieving superior rate performance for potassium storage. • Locally ordered graphitized structure is introduced into mesoporous carbon spheres. • The local graphitization and enriched active sites realize fast reaction kinetics. • The unique structural design enhances the rate performance for potassium storage.