Graphene quantum dot-integrated anodes for lithium-ion batteries: electronic structure, interphase evolution, and...

Graphene quantum dots (GQDs) have emerged as multifunctional nanoscale components for lithium-ion battery anodes, yet their reported benefits are often interpreted without clearly separating intrinsic storage activity from interfacial, conductive, and architectural effects. This review develops a multiscale framework for understanding GQD-integrated anodes through the linked roles of electronic structure, interphase evolution, transport regulation, and electrode organization. It first defines the structural identity of GQDs in terms of confined nanographene domains, edge topology, defect states, dimensionality, and surface chemistry. These features are then translated into functional descriptors governing local reactivity, charge redistribution, interfacial polarization, and coupled ion-electron transport. Experimental evidence across carbon, lithium titanate, metal-oxide, silicon, and silicon-oxide anodes is critically compared to identify recurring structure-property-performance relationships and to distinguish host-dependent GQD functions, including storage-site provision, conductive bridging, interphase regulation, surface protection, and mechanical-contact stabilization. The analysis shows that GQD effectiveness depends less on maximizing defect or dopant content than on matching a controlled GQD configuration to a specific electrode bottleneck. Remaining barriers include uncertain capacity attribution, incomplete interphase characterization, inconsistent material descriptors, limited electrode-level comparability, and manufacturing constraints. A descriptor-guided and failure-aware roadmap is proposed for translating GQD functionality from atomic design to practical anode architectures.