Recent advances of carbon dots in lithium battery materials

Carbon dots (CDs), an emerging class of zero-dimensional carbon nanomaterials, have attracted extensive attention in lithium-based energy storage due to their high specific surface area, tunable surface chemistry, excellent electronic conductivity, and abundant, easily functionalized surface states. Recent advances have demonstrated that CDs can serve as conductive bridges, chemical regulators, and interfacial stabilizers across all key components of lithium batteries, enabling simultaneous optimization of electronic and ionic transport as well as interfacial reactions in cathodes, anodes, and electrolytes. This review systematically summarizes the synthesis strategies and structural classifications of CDs, emphasizing how precursor selection, heteroatom doping, and surface functionalization determine their core-shell structure, defect states, and chemical reactivity. Subsequently, the applications of CDs in cathode modification, anode reinforcement, and electrolyte optimization are discussed in detail, highlighting their roles in enhancing charge-transfer kinetics, modulating ion transport, stabilizing interphases, and suppressing lithium dendrites. Special attention is given to interfacial reconstruction mechanisms driven by heteroatom-doped or functionalized CDs, which simultaneously promote ionic conduction and electron blocking at solid-solid interfaces. Finally, current challenges and future directions are outlined, including predictive synthesis design, interface chemistry optimization, multiscale composite construction, and scalable green fabrication. In general, this review aims to deepen the understanding of CD-mediated interfacial engineering and to provide design guidelines for developing safe, long-life, and high-energy-density lithium-based batteries.