Interfacial electron modulation of MoS2/black phosphorus heterostructure toward high-rate and high-energy density half/full sodium-ion batteries

Abstract

Sodium-ion batteries (SIBs) have been considered as promising candidates for large-scale energy storage. However, viable anode materials still suffer from sluggish electrochemical reaction kinetics and huge volume expansion during cycling, resulting in rapid capacity fading. Herein, an interface confined strategy is developed to construct MoS₂/black phosphorus heterostructure, in which the ultrathin MoS₂ nanosheets are well grown on the black phosphorus flakes through strong interface interactions. The synergistic effect of the MoS₂ nanosheets and black phosphorus flakes is beneficial to enhancing the electron/ion transport kinetics and improving the structure stability upon cycling, leading to superior sodium storage performance. Specifically, the as-synthesized MoS₂/black phosphorus heterostructure shows a high reversible capacity of 435.5 mA h g⁻¹ at 1.0 A g⁻¹ over 150 cycles and a good rate at 10 A g⁻¹ as well as excellent cyclic stability up to 1000 cycles. With the aid of kinetic tests and density functional theory calculations, the sodium storage mechanism can be unraveled. When coupled with the high-voltage Na₃V₂(PO₄)₂O₂F cathode, the full cell delivers a high energy density of 142.9 W h kg⁻¹ at 76.5 W kg⁻¹, suggesting that the MoS₂/black phosphorus heterostructure is a promising candidate to build high-performance SIBs with high energy density and high power density.