Multifunctional ZnCo₂O₄ Quantum Dots Encapsulated In Carbon Carrier for Anchoring/Catalyzing Polysulfides and Self‐Repairing Lithium Metal Anode in Lithium‐Sulfur Batteries

Abstract

Lithium‐sulfur batteries have recently attracted academic/industrial attention due to the high theoretical energy density. However, the capacity decay mainly caused by the polysulfides shuttle effect and poor conductivity of sulfur. Herein, in situ growth of ZnCo2O4 quantum dots (ZCO‐QDs) embedded into the hollow carbon‐carrier sphere (HCS) to form the ZnCo2O4 quantum dots nanocapsule (ZCO‐QDs@HCS) as the multifunctional sulfur host is rationally demonstrated. Based on density‐functional theory calculations, in situ spectroscopic techniques, and electrochemical studies, the synergistic effects on anchoring/catalyzing polysulfide of the ZCO‐QDs@HCS composite in Li‐S batteries is investigated. Interestingly, the ZCO‐QDs@HCS also allows for the controlled release of ZCO‐QDs into the Li‐S electrolyte. Subsequently, it is first discovered that these diffused ZCO‐QDs can act as self‐repairing initiators to stabilize Li metal anodes via rebuilding the damaged solid electrolyte interphase and suppressing Li dendrites growth. With this concept, quantum dots‐based catalyst delivery systems is first constructed in a Li‐S battery, which is similar to the use of nanocarrier‐based drug delivery systems in cancer therapy. The Li‐S cells with the S@ZCO‐QDs@HCS cathode display significantly superior electrochemical performances with a high specific capacity (1350.5 mAh·g−1 at 0.1 C) and excellent cycling stability (capacity decay rate of 0.057% per cycle after 1000 cycles at 3.0 C).

Wide-Temperature-Range Li–S Batteries Enabled by Thiodimolybdate [Mo2S12]2– as a Dual-Function Molecular Catalyst for Polysulfide Redox and Lithium Intercalation

“…To understand the mechanism of [Mo 2 S 12 ] 2– clusters catalyzing the kinetics of LiPSs redox reactions, the discharging/charging process was investigated by in situ visual electrochemical reactions (Figures a,b and S14). The Li–S cuvette cells with a high S loading of 5.0 mg cm –2 introduced the soluble and uncaptured LiPSs into the electrolyte. The cells were initially discharged and then charged at 0.05 C for in situ electrochemical studies.…”

[Mo3S13]2−as bidirectional cluster catalysts for high-performance Li–S batteries

“…3c). 30 XPS analysis verified the chemical interactions between [Mo 3 S 13 ] 2− clusters and Li 2 S (Fig. 3d).…”

Insight into the Catalytic Role of Defect-Enriched Vanadium Sulfide for Regulating the Adsorption–Catalytic Conversion Behavior of Polysulfides in Li–S Batteries

“…The change in valence is usually attributed to the introduction of S vacancies, and thus it can be inferred that the value of x in VS 2– x is 0.19. After absorption of Li 2 S 4 , it can be seen that the binding energy peak of V 2p shifts about 0.13 eV toward the low binding energy direction, indicating that CC@VS 2– x may accept some electrons from Li 2 S 4 , and thus the polysulfides can be captured . Because of the strong chemical interactions between CC@VS 2– x and polysulfides, CC@VS 2– x shows a good catalysis that can promote the fast conversion of lithium polysulfides.…”