A Robust Ternary Heterostructured Electrocatalyst with Conformal Graphene Chainmail for Expediting Bi-Directional Sulfur Redox in Li-S Batteries

Designing high-performance electrocatalysts for boosting aprotic electrochemistry is of vital importance to drive longevous Li-S batteries. Nevertheless, investigations on probing the electrocatalytic endurance and protecting the catalyst activity yet remain elusive. Here, a ternary graphene-TiO2/TiN (G-TiO2/TiN) heterostructure affording conformal graphene chainmail is presented as an efficient and robust electrocatalyst for expediting sulfur redox kinetics. The G-TiO2/TiN heterostructure synergizes adsorptive TiO2, catalytic TiN, and conductive graphene armor, thus enabling abundant anchoring points for polysulfides and sustained active sites to allow smooth bi-directional electrocatalysis. Encouragingly, in situ crafted graphene chainmail ensures favorable protection of inner TiO2/TiN to retain their catalytic robustness towards durable sulfur chemistry. As expected, sulfur cathodes mediated by ternary G-TiO2/TiN harvest an impressive rate capability (698.8 mAh g(-1) at 5.0 C), favorable cycling stability (a low decay of 0.054% per cycle within 1000 cycles), and satisfactory areal capacity under elevated loading (delivering 8.63 mAh cm(-2) at a sulfur loading of 10.4 mg cm(-2)). The ternary heterostructure design offers an in-depth insight into the electrocatalyst manipulation and protection toward long lifespan Li-S batteries.

Automated summary

The ternary graphene-TiO2/TiN heterostructure is an efficient and robust electrocatalyst for accelerating sulfur redox kinetics, providing abundant anchoring points and sustained active sites for smooth bi-directional electrocatalysis.