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.