N/O Dual‐Doped Environment‐Friendly Hard Carbon as Advanced Anode for Potassium‐Ion Batteries

Abstract

Abstract Potassium‐ion batteries (PIBs) are considered as promising candidates for lithium‐ion batteries due to the abundant reserve and lower cost of K resources. However, K+ exhibits a larger radius than that of Li+, which may impede the intercalation of K+ into the electrode, thus resulting in poor cycling stability of PIBs. Here, an N/O dual‐doped hard carbon (NOHC) is constructed by carbonizing the renewable piths of sorghum stalks. As a PIB anode, NOHC presents a high reversible capacity (304.6 mAh g−1 at 0.1 A g−1 after 100 cycles) and superior cycling stability (189.5 mAh g−1 at 1 A g−1 after 5000 cycles). The impressive electrochemical performances can be ascribed to the super‐stable porous structure, expanded interlayer space, and N/O dual‐doping. More importantly, the NOHC can be prepared in large scale in a concise way, showing great potential for commercialization applications. This work may impel the development of low‐cost and sustainable carbon‐based materials for PIBs and other advanced energy storage devices.

Keywords

• hard carbon
• low cost
• N/O dual doping
• potassium‐ion batteries
• sorghum stalks