The dual-function sacrificing template directed formation of MoS2/C hybrid nanotubes enabling highly stable and ultrafast sodium storage

Abstract

The constantly increasing demand for energy has forced an unprecedented desire for the utilization of sustainable energy resources due to the arousal of environmental concerns derived from the overconsumption of fossil fuels; this has drastically stimulated the development of advanced energy storage systems. Recently, sodium-ion based energy storage devices, including sodium-ion batteries (SIBs) and hybrid capacitors (NIHCs), have aroused a tremendous amount of attention, since these devices could potentially address the unaffordable cost of lithium-ion batteries (LIBs) as a power supply for large-scale grid-level applications. Currently, the common challenge related to sodium-ion based energy storage devices is the lack of appropriate anode candidates with ultrafast yet ultrastable sodium storage capabilities because of the sluggish kinetics and relatively larger radius of Na⁺ (1.02 Å) compared to Li⁺ (0.67 Å). Herein, a unique dual-function sacrificing template directed strategy has been developed for the construction of MoS₂/carbon hybrid nanotubes (denoted MoS₂/C-HNTs) with a strong coupling effect, which can be further extended to the synthesis of WS₂/C-HNTs, Mo_0.5W_0.5S₂/C-HNTs and MoSSe/C-HNTs with slight modifications. MoS₂/C-HNTs exhibit extraordinary sodium storage performance in terms of high specific capacity, superior rate performance and ultralong cycle life. More importantly, sodium-ion based hybrid capacitors (NIHCs) with a MoS₂/C-HNT anode and a commercial activated carbon (AC) cathode deliver a maximum energy density of 107.2 W h kg⁻¹ at a power density of 198 W kg⁻¹ and exhibit excellent cycling stability with 74.4% capacity retention after 5000 cycles at a high current density of 2 A g⁻¹. This demonstrates the highly promising application of this material as a candidate anode for sodium-ion based energy storage devices.