Design of High-Capacity MoS3 Decorated Nitrogen Doped Carbon Coated Cu2 S Electrode Structures with Dual Heterogenous Interfaces for Outstanding Sodium-Ion Storage

Abstract

The hierarchical Cu₂ S@NC@MoS₃ heterostructures have been firstly constructed by the high-capacity MoS₃ and high-conductive N-doped carbon to co-decorate the Cu₂ S hollow nanospheres. During the heterostructure, the middle N-doped carbon layer as the linker facilitates the uniform deposition of MoS₃ and enhances the structural stability and electronic conductivity. The popular hollow/porous structures largely restrain the big volume changes of active materials. Due to the cooperative effect of three components, the new Cu₂ S@NC@MoS₃ heterostructures with dual heterogenous interfaces and small voltage hysteresis for sodium ion storage display a high charge capacity (545 mAh g^-1 for 200 cycles at 0.5 A g^-1 ), excellent rate capability (424 mAh g^-1 at 15 A g^-1 ) and ultra-long cyclic life (491 mAh g^-1 for 2000 cycles at 3 A g^-1 ). Except for the performance test, the reaction mechanism, kinetics analysis, and theoretical calculation have been performed to explain the reason of excellent electrochemical performance of Cu₂ S@NC@MoS₃ . The rich active sites and rapid Na⁺ diffusion kinetics of this ternary heterostructure is beneficial to the high efficient sodium storage. The assembled full cell matched with Na₃ V₂ (PO₄ )₃ @rGO cathode likewise displays remarkable electrochemical properties. The outstanding sodium storage performances of Cu₂ S@NC@MoS₃ heterostructures indicate the potential applications in energy storage fields.

Keywords: N-doped carbon; amorphous MoS3; heterostructures; hollow Cu2S; sodium ion batteries.