Bromine-Modified Graphite for High-Rate and Stable K-Storage

Graphite (Gr) has been considered as one of the most promising anode materials for potassium-ion batteries (PIBs) due to its low cost, high electrical conductivity, good chemical stability, and ability to reversibly form intercalation compounds with K⁺. However, the large ionic radius of K⁺ results in sluggish K-storage kinetics and irreversible disruption of the Gr structure during insertion/extraction, leading to unsatisfactory cycling stability and rate performance. In this work, a bromine-modified Gr-based composite (Br-Gr) was synthesized via a hexabromobenzene (HBB)-assisted one-step carbonization method. As a result, the optimized Br-Gr demonstrates a reversible discharge capacity of 310.1 mA h g^-1 at a current density of 50 mA g^-1 as well as a high-rate capacity of 109.5 mA h g^-1 at 1000 mA g^-1, along with excellent cycling stability and high reaction reversibility. This work presents a practical, cost-effective strategy for preparing high-performance Gr-based K-storage anode materials with promising commercial applications in PIBs.