Carbonaceous materials have been accepted as a promising family of anode materials for lithium‐ion batteries (LIBs) owing to optimal overall performance. Among various emerging carbonaceous anode materials, hard carbons have recently gained significant attention for high‐energy LIBs. The most attractive features of hard carbons are the enriched microcrystalline structure, which not only benefits the uptake of more Li+ ions but also facilitates the Li+ ions intercalation and deintercalation. However, the booming application of hard carbons is significantly slowed by the low initial Coulombic efficiency, large initial irreversible capacity, and voltage hysteresis. Many efforts have been devoted to address these challenges toward practical applications. This paper focuses on an up‐to‐date overview of hard carbons, with an emphasis on the lithium storage fundamentals and material classification of hard carbons as well as present challenges and potential solutions. The future prospects and perspectives on hard carbons to enable practical application in next‐generation batteries are also highlighted.

Lithium- (Li-) ion batteries have revolutionized our daily life towards wireless and clean style, and the demand for batteries with higher energy density and better safety is highly required. The next-generation batteries with innovatory chemistry, material, and engineering breakthroughs are in strong pursuit currently. Herein, the key historical developments of practical electrode materials in Li-ion batteries are summarized as the cornerstone for the innovation of next-generation batteries. In addition, the emerging electrode materials for next-generation batteries are discussed as the revolving challenges and potential strategies. Finally, the future scenario of high-energy-density rechargeable batteries is presented. The combination of theory and experiment under multiscale is highlighted to promote the development of emerging electrode materials.

Phosphorus doping is an effective approach to tailor the surface chemistry of carbon materials. In this work, two-dimensional graphene, as a simplified model for all sp 2 hybrid carbon allotropes, is employed to explore the surface chemistry of P-doped carbon materials. Thermally reduced graphene oxide, with abundant residual oxygen functionalities, is doped by phosphorus heteroatoms through H 3 PO 4 activation, followed by passivation in an inert atmosphere. The structural evolution of the phosphorus species in the carbon lattice during the thermal treatment is systematically studied by Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, X-ray diffraction, and Raman spectroscopy with the assistance of first-principles calculations. The C 3 −PO configuration is identified as the most stable structure in the graphene lattice and plays a key role in stabilizing the electrochemical interface between the electrode and electrolyte. These features enable an electrode based on P-doped graphene to exhibit an enlarged potential window of 1.5 V in an aqueous electrolyte, a remarkable improved cycling stability, and an ultralow leak current. Therefore, this contribution provides insights for designing phosphorus-doped carbon materials toward electrocatalysis, energy-related applications, and so forth.