Architecture‐Interface Co‐Design of g‐C ₃ N ₄ Driven Dry Thick Cathodes Enabling Fast Li‐Ion Transport

ABSTRACT

Overcoming ionic transport limitations in thick‐film electrodes is a central challenge for next‐generation high‐energy‐density lithium‐ion batteries. Here, we report an architecture‐interface co‐design strategy for solvent‐free dry thick cathodes, introducing nanostructured graphitic carbon nitride (g‐C ₃ N ₄ ) as a multifunctional ion‐transport promoter, representing the first demonstration of its application as a cathode additive. Mechanistic studies reveal that g‐C ₃ N ₄ operates via a dual mechanism, simultaneously enhancing electrolyte wettability and accelerating Li ⁺ transport kinetics through transient Li‐N coordination that effectively lowers the desolvation energy barrier. High‐resolution 3D X‐ray nanotomography and pore network modeling quantitatively map the ionic‐mechanical trade‐off arising from compressive spring‐back in the dry process, directly guiding the optimization of electrode architecture. The resulting single‐layer dry electrode (∼21.5 mg cm ⁻² , ∼68 µm thick) delivers a 165.9% capacity increase at 3C and a 2.85‐fold enhancement in power density, while achieving markedly improved cyclic stability with 81.3% capacity retention after 600 cycles. Furthermore, a functionally graded dual‐layer design (∼42.2 mg cm ⁻² , ∼113 µm thick) yields a 62.5% capacity gain at 1C. This work establishes a generalizable, scalable, and sustainable pathway for engineering high‐performance dense electrodes.