Recent advances of carbon dots in lithium battery materials

Carbon dots (CDs), an emerging class of zero-dimensional carbon nanomaterials, have attracted extensive attention for lithium-based energy storage due to their high specific surface area, tunable surface chemistry, excellent electronic conductivity, and abundant, readily 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 the 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 structures, 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 dendrite formation. 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, interfacial chemistry optimization, multiscale composite construction, and scalable green fabrication. Overall, this review aims to deepen the understanding of CD-mediated interfacial engineering and to provide design guidelines for the development of safe, long-life, and high-energy-density lithium-based batteries.