Unraveling the improved lithium-storage mechanism by interfacial engineering based on metallic MoS2/MoN heterostructure

Abstract

The boom in anode materials with the splendid electrochemical performance of lithium-ion batteries (LIBs) is key to meet energy storage. As a typical anode material with the good capacity property and sandwich structure, molybdenum disulfide (MoS2) exhibited the poor lithium storage performance owing to the inferior conductivity and rapid capacity decay. Introducing a highly conductive material into MoS2 to construct a rational heterostructure is an effective strategy to tackle this challenge. Herein, we prepared MoS2 by a simple hydrothermal method and then successfully synthesized MoS2/MoN heterostructure by calcination under NH3 atmosphere. Density functional theory (DFT) calculation results show that the MoS2/MoN heterostructure with strong chemical bonding at the interface of MoS2 and MoN can enhance lithium storage, which are well verified by our experimental results. The experiment and calculation results reveal that the MoS2/MoN heterostructure shows the improved electrical conductivity after introducing metallic MoN, thus promoting the diffusion of electrons and Li+ ions. Moreover, due to the synergistic effect and the action of strong built-in electric field, the MoS2/MoN heterostructure exhibits higher initial discharge capacity and theoretical maximum capacity, as well as the better rate performance. This study offers possible approaches for the development of high-performance heterostructure-based anode materials in LIBs and other electrochemical energy storage (EES) devices.