MoO2–Stabilized MoS2 Heterojunction Catalyst for Enhanced Lithium–Sulfur Battery

Abstract

Heterojunction materials are characterized by high design adjustability, which accounts for their wide application in various catalytic fields. In this work, a MoO₂–MoS₂ heterojunction catalyst with MoO₂ serving as a stabilizer was fabricated via the semisulfidation treatment on the surface of carbon nanotube (CNT) and employed as the cathode host material for lithium–sulfur batteries (LSBs). The introduction of MoO₂ effectively mitigates the aggregation of MoS₂, enabling a rich distribution of active sites. Moreover, it can enhance the redox stability and bring about the antipolarization effect under high current densities, thereby fully unleashing the inherent high catalytic activity of MoS₂. This unique heterojunction host material not only accelerates the multistep transformation of lithium polysulfides (LiPSs) and reduces the nucleation energy barrier of Li₂S but also demonstrates outstanding stability along with high safety. The assembled Li–S batteries exhibit remarkable cycling stability, with an average decay rate of only 0.05% over 400 cycles at 1 C. Significantly, the pouch cells assembled with a high sulfur loading of 6.4 mg cm^–2 and a low E/S ratio of 4 μL mg^–1 achieve a high areal capacity of 8 mAh cm^–2, which implies broad practical prospects.