Synthesis of faveolate open-structured Ru-N/C cathode catalyst with high bifunctional activity for rechargeable quasi-solid-state Li-O₂ batteries

The constituents and geometric design of cathodic electrocatalyst to achieve high activity and durability are effective but challenging for the development of high-performance Li-O₂ batteries. This study employs a mild solution precipitation method followed by thermolysis to construct a faveolate open-structured Ru-N/C matrix with a loosely braided network morphology as a bifunctional cathode. The details prove that this hybrid structure is composed of ultrafine Ru globular nanoparticles (ca. 2 nm) coated with an N-enriched carbon film and exhibits a valuable beehive through-hole character for rapid mass transport during oxygen redox catalysis. The synergistic effect of open-structured and reticular network matrix with metal–N₄ coordination induces asymmetric charge distributions with moderate adsorption/desorption behaviour with oxygen intermediates. Consequently, this particular Ru-N/C matrix cathode provides a promising Li₂O₂ accommodation space and exhibits superior electrochemical performance in terms of a positive discharge plateau and low charge overpotential. Besides, the assembled batteries also present a high discharge capacity and a long cycle life (exceeding 283 cycles). The density functional theory (DFT) calculations also corroborate the assertion that the Ru-N/C catalyst exhibits robust electronic coupling transfer and superior bifunctional activity. As such, our work demonstrates that this type of open-structured Ru-N/C matrix is promising for fabricating high-performance quasi solid-state Li-O₂ batteries.