RuO x Quantum Dots Loaded on Graphdiyne for High-Performance Lithium-Sulfur Batteries.

The practical application of lithium-sulfur (Li-S) batteries is impeded by shuttle effect and sluggish conversion kinetics of lithium polysulfides (LiPSs) on the cathode and Li dendrite growth on the anode. Here, we report a strategy to strengthen d-p orbital hybridization by fabricating π back-bonding in the catalyst for efficient LiPSs conversion. A special interface structure of RuO x quantum dots (QDs) anchored on graphdiyne (GDY) nanoboxes (RuO x QDs/GDY) is prepared to enable strong Ru-to-alkyne π back-donation, which effectively regulates the d-electron structures of Ru centers to promote the d-p orbital hybridization between the catalyst and LiPSs and significantly boosts the catalytic performance of RuO x QDs/GDY. The strong affinity with Li ions and fast Li-ion diffusion of RuO x QDs/GDY also enable ultra-stable Li metal anodes. Thus, S@RuO x QDs/GDY cathodes exhibit excellent cycling performance under harsh conditions, and Li@RuO x QDs/GDY anodes show an ultra-long cycling life over 8800 h without Li dendrite growth. Li-S full cells with S@RuO x QDs/GDY cathodes and Li@RuO x QDs/GDY anodes can deliver an impressive areal capacity of 17.8 mA h cm -2 and good cycling stability under the practical conditions of low negative-to-positive electrode capacity (N/P) ratio (N/P = 1.4), lean electrolyte (E/S = 3 μL mg -1 ) and high S mass loading (15.4 mg cm -2 ). This article is protected by copyright. All rights reserved.