Rigid-Flexible Coupling Realized by Synergistic Engineering of the Graphitic-Amorphous Architecture for Durable and Fast Potassium Storage.

Graphite anodes hold great potential for potassium-ion batteries (PIBs), yet their practical application is hindered by poor cycle performance caused by substantial interlayer expansion. Herein, a partial graphitic carbon (PGC) is elaborately engineered via the catalytic effect of ferric citrate using pitch as a carbon precursor. Systematically varying the catalyst content enables an optimal PGC design integrating a highly graphitized phase providing abundant active sites for K-ion intercalation, balanced with an amorphous carbon region that accommodates volume expansion and facilitates ion diffusion. The optimized PGC12 electrode exhibits a high reversible capacity of 281.9 mAh g, characterized by a prolonged low-potential plateau region, and excellent cycle stability with a capacity retention of 94.8% after 300 cycles. It also realizes an impressive rate capability with a retained capacity of 222.2 mAh g at 1 C. Moreover, the assembled K-ion full-cell delivers an exceptional energy density of 148.2 Wh kg. In-situ XRD and DFT simulations further verify the distinct phase transition mechanisms and reaction dynamics across different carbon configurations. This work elucidates the impact of carbon configurations on K-storage performance and proposes a structural model for efficient K-ion storage, which is instrumental in the rational design and advancement of carbon anodes in PIBs.