▎ 摘　　要

The development of high-performance carbon-based anode materials is still a significant challenge for K -ion storage. In our work, we designed reduced graphene oxide coating carbon sub-microspheres hierar-chical nanostructure (CS@RGO) hierarchical nanostructure via a simple freeze-drying and subsequent pyrolysis as anode for K-ion batteries (KIBs), which presented an excellent electrochemical performance for K-ion storage, with a reversible specific capacity of 295 mAh g (1) after 100 cycles at 100 mAh g (1) . Even at a high current density of 1 A g (1), our CS@RGO still achieves ultra-stable K-ion storage of 200 mAh g 1 at 1 A g (1) after 5000 cycles almost without capacity fade. According to the galvanostatic intermittent titration technique result, the CS@RGO hybrid receives a high average diffusion coefficient of 7.35 x 10 (8) cm(2) s (1), contributing to the rapid penetration of K-ion, which facilitates the enhancement of electrochemical performance for KIBs. Besides, we also use Raman spectra to investigate the electro-chemical behavior of our CS@RGO hybrid for K-ion storage and confirm the reaction process. We believe that our work will offer the opportunity to enable ultra-stable carbon-based materials by the structure design in the K-ion battery field. (c) 2022 Elsevier Inc. All rights reserved.