Embedding Cobalt Atom Clusters in CNT‐Wired MoS₂ Tube‐in‐Tube Nanostructures with Enhanced Sulfur Immobilization and Catalyzation for Li–S Batteries

Abstract

Abstract Lithium–sulfur batteries are one of the most promising next‐generation energy storage systems. The efficient interconversion between sulfur/lithium polysulfides and lithium sulfide is a performance‐determining factor for lithium–sulfur batteries. Herein, a novel strategy to synthesize a unique tube‐in‐tube CNT‐wired sulfur‐deficient MoS 2 nanostructure embedding cobalt atom clusters as an efficient polysulfide regulator is successfully conducted in Li−S batteries. It is confirmed that encapsulating MWCNTs into hollow porous sulfur‐deficient MoS 2 nanotubes embedded with metal cobalt clusters not only can accelerate electron transport and confine the dissolution of lithium polysulfide by physical/chemical adsorption, but also can catalyze the kinetics of polysulfide redox reactions. Based on DFT calculations, in situ spectroscopic techniques, and various electrochemical studies, catalytic effects of CNT/MoS 2 ‐Co nanocomposite in Li–S battery are deeply investigated for the first time. The CNT/MoS 2 –Co composite cathode exhibits a very remarkable rate capability (641 mAh g −1 at 5.0 C) and excellent cycling stability (capacity decay rate of 0.050% per cycle at 5.0 C) even at high sulfur mass loading of 3.6 mg cm −2 . More crucially, CNT/MoS 2 ‐Co tube‐in‐tube nanostructures present a superior specific capacity of 650 mAh g −1 in a Li–S pouch cell at 0.2 C (4.0 mg cm −2 ).