<p>Carbon anodes for potassium-ion batteries (PIBs) are currently limited by insufficient cycle stability and rate capability, stemming from the sluggish kinetics caused by the large-radius potassium and tortuous diffusion pathways. Herein, we propose an interconnected lotus-root-like multichannel carbon nanofiber, where seamlessly stacked hollow graphitic carbon spheres are integrated by an ultrathin 3–5&#xa0;nm amorphous carbon buffer layer. This creates heterogeneous curvature interfaces that boosts electron transfer, with the additional benefit of structural stress mitigation by the buffer layer. Moreover, the internal multichannel structure shortens the potassium-ion transport pathways, thereby enhancing ion-transport efficiency within the porous carbon electrode. This dual optimization of the electronic and mechanical frameworks delivers outstanding electrochemical metrics, specifically superior rate capability (162.9 mAh g⁻¹ at 5 A g⁻¹) and robust cycling stability (stable 3000 cycles at 5 A g⁻¹). Our work demonstrates that by engineering the internal ion channels and amorphous/graphitic composition, the porous fibers achieve superior rate capability and cycling endurance, which suggests a design strategy for developing high-performance carbon anodes.</p> Graphical Abstract <p> </p>