Vertically Aligned MoS2 Nanosheets with Increased Interlayer Spacing on Hollow Polypyrrole Nanotubes for Enhanced Lithium and Sodium Storage Performance

Abstract

MoS₂ is the most promising anode material for secondary battery with its unique 2D layered structure. However, the application of MoS₂ is restricted by the poor electrical conductivity and sluggish ion diffusion. Herein, hollow nanotubes constructed with highly conductive 1T phase MoS₂ nanosheets and polypyrrole (PPy) nanotubes are fabricated and used as anode materials for lithium-ion batteries and sodium-ion batteries. Remarkably, these hollow nanotubes show a high lithium-specific capacity of 755.5 mAh g⁻¹ at 100 mA g⁻¹ and excellent sodium-specific capacity of 503.3 mAh g⁻¹ after 200 cycles. The enhanced electrochemical performance can be attributed to the rational design of unique 1D and 2D composite structure. First, the highly conductive 1T phase MoS₂ 2D nanosheets and hollow 1D PPy nanotube can effectively promote the charge transfer kinetics. However, the increased interlayer spacing of 1T phase MoS₂ rapidly improves the insertion/extraction process of metal ions, and the vertical growth of MoS₂ nanosheets on the surface of the PPy nanotubes also exposes more energy storage sites. This work provides a new idea for the preparation of MoS₂-based composite materials, and also proposes a reference for its application in the secondary battery.