A MoO3/MoO2-CP self-supporting heterostructure for modification of lithium–sulfur batteries

Abstract

Heterostructures have attracted extensive attention because of their unique structure and multiple functions, showing potential for various energy storage and conversion techniques. Here, inspired by the potential advantages of heterostructures, we design an insulating MoO₃/conducting MoO₂ heterostructure as a host for lithium octasulfide (Li₂S₈) for lithium–sulfur batteries. Different from other heterostructures with a sharp interface, the transition state of MoO_x is proved to have a large atomic ratio (∼18%). Benefiting from the good conductivity of MoO₂ and the strong polarity of MoO_x to adsorb LiPS, the initial specific capacity of the MoO₃/MoO₂-CP-Li₂S₈ cathode is 898.4 mA h g⁻¹ and drops to 828.1 mA h g⁻¹ after 500 cycles at 0.5C, showing a 92.2% retention of the initial capacity. Meanwhile, it can deliver an initial specific capacity of 580.5 mA h g⁻¹ at 2.5C with a capacity retention of 82.8% after 850 cycles. This work shows that the heterostructures of 2D materials are promising as a Li₂S₈ host because of their multiple functions and may provide new strategies to design electrochemical electrodes.