A Low-Strain Cathode by sp-Carbon Induced Conversion in Multi-Level Structure of Graphdiyne.

A multi-level architecture formed alternatively by the conformal graphdiyne (GDY) and CuS is well engineered for Li-free cathode. Such a proof-of-concept architecture efficiently integrates the advantages of GDY and produces new functional heterojunctions (sp-C-S-Cu hybridization bond). The layer-by-layer 2D confinement effect successfully avoids structural collapse, the selective transport inhibits the shuttling of active components, and the interfacial sp-C-S-Cu hybridization bond significantly regulates the phase conversion reaction. Such new sp-C-S-Cu hybridization of GDY greatly improves the reaction dynamics and reversibility, and the cathode delivers an energy density of 934 Wh kg and an unattenuated lifespan of 3000 cycles at 1 C. Our results indicate that the GDY-based interface strategy will greatly promote the efficient utilization of the conversion-type cathodes.