Construcción de trampas iónicas impulsadas por defectos y modulación de la interfaz para una cinética rápida de Li⁺...

Composite solid electrolytes (CSEs) hold great promise for lithium metal batteries owing to the inherent safety and mechanical flexibility, yet their progress is impeded by sluggish Li⁺ transport and unstable interfacial chemistry. Herein, we unveil an ionic-trap framework to clarify the essential role of inorganic fillers in regulating ion migration. Specifically, milled carbon nitride with oxamide incorporation (MCNOI) introduces abundant nitrogen vacancies that function as a shallow ionic trap, enabling reversible Li⁺ capture/release and constructing continuous conduction pathways. By contrast, traditional carbon nitride forms a deep ionic trap that immobilizes Li⁺, whereas ionic trap-free polymer electrolytes lack effective guidance for Li⁺ transport. Beyond intrinsic ion conduction, MCNOI facilitates the formation of a gradient organic-inorganic interphase, redistributing interfacial charges, suppressing anion migration, and promoting uniform Li deposition. Consequently, the optimized CSE achieves a high Li⁺ transference number (0.68), ultralong cycling stability (>3000 h), and remarkable full-cell durability (92.3% capacity retention after 1800 cycles at 5 C). These findings highlight defect-engineered fillers as active regulators of Li⁺ transport, redefining design strategies for durable high-performance solid-state batteries.