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

Abstract

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.

CoNiO2/Co4N Heterostructure Nanowires Assisted Polysulfide Reaction Kinetics for Improved Lithium–Sulfur Batteries

“…The conversion kinetics of as-prepared samples was more obvious in symmetrical cell based on Li 2 S 6 catholyte (Figure 5d). [4] From the CV curves in Figure 5e, except for graphene, the other electrodes showed two distinct redox peaks and high response current, indicating easy conversion between Li 2 S n and Li 2 S 2 /Li 2 S. [47] The redox peak of CoNiO 2 /Co 4 N sample provided the highest intensity and smallest polarization, which was in good agreement with the electrochemical impedance spectroscopy (EIS) results (Figure 5f) for symmetric cells. The charge transfer resistance of symmetrical cell increased in the order of CoNiO 2 /Co 4 N<Co 4 N<CoNiO 2 <graphene, suggesting that the introduction of heterostructure resulted in the obvious improvement in polysulfide conversion kinetics.…”

Synergetic Anion Vacancies and Dense Heterointerfaces into Bimetal Chalcogenide Nanosheet Arrays for Boosting Electrocatalysis Sulfur Conversion

“…[6,7] An electrocatalytic approach to boost sulfur conversion reaction in Li−S chemistry has recently been proposed as an effective strategy to overcome these limitations. [8][9][10][11][12] Transition metal chalcogenides (TMCs) are recognized to be effective sulfur electrocatalysts because of their abundance, environment friendliness, and unique electrochemical properties. [13][14][15][16][17] Among them, metal sulfides arouse particular interest because of their high activity, and thermodynamically stable structures.…”

NiCo (oxy)selenide electrocatalysts via anionic regulation for high-performance lithium–sulfur batteries

“…5f, which revealed the smallest Tafel slope of 79 mV dec À1 for NiCo-LDH-Se-2, compared with those of NiCo-LDH-Se-0 (248 mV dec À1 ), NiCo-LDH-Se-1 (183 mV dec À1 ), and NiCo-LDH-Se-4 (137 mV dec À1 ), demonstrating its good oxidation ability towards Li 2 S 2 /Li 2 S and LiPSs conversion. 45 Based on these results, the superb SRR performance could be reasonably attributed to the unique electronic structure of the selenided materials with abundant active sites for LiPSs conversion. Additionally, the catalytic effect on the conversion from S 8 to LiPSs was also demonstrated by comparison of the LSV and Tafel plots (Fig.…”