Multifunctional α-MoO₃ Nanobelt Interlayer with the Capacity Compensation Effect for High-Energy Lithium–Sulfur Batteries

Abstract

Spatial hindrance of lithium polysulfide (LiPS) diffusion by inserting a barrier interlayer has been deemed as an effective strategy to restrict the shuttle effect in lithium-sulfur batteries (LSBs). However, the extra interlayer without reversible capacity production inevitably reduces the actual energy density of the battery. Herein, a freestanding α-MoO₃ nanobelt interlayer with the decoration of TiN nanoparticles and carbon nanotubes (denoted as MCT) is established. To investigate the capacity compensation effect of the MCT during cell operations, X-ray absorption near-edge spectrometry is conducted. It is revealed that MoO₃ can sustain a reversible Li intercalation/deintercalation in a voltage range of 1.8-2.8 V, providing 180 mAh g^-1 of extra capacity for compensating sulfur cathode. In addition, the adsorption of the lithiated α-MoO₃ toward LiPSs is further evaluated. By matching a high-loading sulfur cathode (3.0 mg cm^-2), a superior capacity of 713.3 mAh g^-1 can be retained after 100 cycles under the MCT assistance.