Cobalt and oxygen double doping induced C@MoS2–CoS2–O@C nanocomposites with an improved electronic structure and increased active sites as a high-performance anode for sodium-based dual-ion batteries

Abstract

A cobalt-doping induced heterogeneous structure of MoS₂–CoS₂ grown on one-dimensional tubular carbon (ODTC) has been synthesized. The CoS₂ nanoparticles can inhibit the free growth of MoS₂ nanosheets and obtain a MoS₂–CoS₂ heterostructure with an ultra-small size, which improves the electronic conductivity of the electrode material affected by the internal electric field. Furthermore, oxygen-incorporated C@MoS₂–CoS₂ accompanied by a double carbon coating process can add active sites, provide a buffer layer and further improve the electronic conductivity of the electrode material, which overcomes the shortcomings of intrinsic low electronic conductivity and structural instability of MoS₂. Serving as an anode material for sodium ion batteries, the C@MoS₂–CoS₂–O@C nanocomposites show superior sodium storage performance with high capacity (466.1 mA h g⁻¹ at 1 A g⁻¹ after 200 cycles) and excellent rate capability. And the sodium dual-ion full batteries deliver a reversible discharge capacity of 182.2 mA h g⁻¹ at 1 A g⁻¹ over the voltage range of 1.0–4.4 V after 1000 cycles.