Nanostructure and Interface Engineering of Graphite Anodes for High-Performance Potassium-Ion Batteries: Mechanisms, Strategies, and Perspectives

Potassium-ion batteries (PIBs) have emerged as a promising next-generation energy storage technology due to the abundance of potassium resources, low redox potential of K⁺/K, and compatibility with aluminum current collectors. Graphite, as a cost-effective and structurally stable anode, exhibits considerable potential for practical PIB applications. However, challenges such as sluggish K⁺ diffusion kinetics, significant volume expansion, and unstable solid electrolyte interphase (SEI) hinder the full utilization of the graphite anode. This review systematically summarizes recent advances in understanding the K⁺ intercalation behavior and storage mechanism of graphite. Key strategies for enhancing graphite performance, including interlayer spacing regulation, morphological engineering, defect and heteroatom doping, and coating design, are thoroughly discussed. In addition, interface engineering approaches involving electrolyte component optimization, artificial SEI construction, and binder design are highlighted to address SEI instability. This review also compares the potassium storage characteristics of graphite with those in lithium/sodium systems and outlines current challenges under extreme conditions. Finally, future perspectives are provided to guide the rational design of graphite-based anodes for high-performance PIBs. This work aims to offer a comprehensive reference for the development of advanced graphite anode materials in emerging potassium-ion battery technologies.