KOH-treated mesocarbon microbeads used as high-rate anode materials for potassium-ion batteries

Graphite is one of the most promising anode materials for potassium-ion batteries (PIBs) due to its low cost and stable discharge plateau. However, its poor rate performance still needs to be improved. A novel graphitic anode was designed from commercial mesocarbon microbeads (MCMBs) by KOH treatment. Using limited oxidation and slight intercalation, the interlayer spacing of graphitic layers on the surface of the MCMBs was increased, causing the K⁺ diffusion rate to be significantly improved. When this modified material was combined with carboxymethyl cellulose as a binder (79.2%) and used as a PIB anode, it had a high plateau capacity below 0.25 V (271 mAh g⁻¹), superior rate capability (160 mAh g⁻¹ at 1.0 A g⁻¹), excellent cycling stability (about 184 mAh g⁻¹ after 100 cycles at 0.1 A g⁻¹), and a high initial coulombic efficiency. This work provides a simple strategy to prepare graphitic materials with an excellent potassium storage performance.