Graphite as anode materials: Fundamental mechanism, recent progress and advances

Graphite is a perfect anode and has dominated the anode materials since the birth of lithium ion batteries, benefiting from its incomparable balance of relatively low cost, abundance, high energy density, power density, and very long cycle life. Recent research indicates that the lithium storage performance of graphite can be further improved, demonstrating the promising perspective of graphite and in future advanced LIBs for electric vehicles and grid-scale energy storage stations. However, to obtain graphite electrodes with higher performance, it is essential to deeply understand the fundamentals of graphite and Li-graphite intercalation compounds (GICs), especially their crystal and electronic structures, and thus to regulate the structure to boost the kinetics of Li ion intercalation, storage, and diffusion in graphite. We introduce the crystal and electronic properties of pristine graphite and Li-GICs, specifically focusing on the development of theoretical calculations and their application in elucidating the band structure, stages, and phase stabilities of graphite and Li-GIC. Based on these fundamental aspects, the experimental researches on thermodynamics/kinetics, including electrochemical potential and Li diffusion rate of graphite anodes, are reviewed. Several key challenges and issues towards advanced graphite anodes with superior rate/capacity/cycle performances are discussed. In addition, advances of graphite and related materials for Na+/K+ storage are briefly summarized. Finally, we propose a series of promising strategies to improve the performance of graphite and recommend several research directions towards rational graphite anode design.