Few-layer MoS2 embedded in N-doped carbon fibers with interconnected macropores for ultrafast sodium storage

Abstract Sodium-ion battery has been considered as one of the most promising next-generation rechargeable energy storage devices. However, it remains a great challenge to exploit suitable electrode materials for sodium storage owing to relatively large radius of Na+. In this study, a novel 1D fiber-like electrode material integrating few-layer MoS2, ultrathin carbon continuous framework, doped N atoms and well-defined 3D connected macropores is developed by electrospinning (denoted as MoS2/NCF-MP). When used as anode in sodium ion battery, its unique structural hierarchy is able to maximumly diminish the solid-state diffusion length, lower electrochemical resistance, accelerate Na+ transfer from bulk to electrode, and relieve the volume variation during sodiation/desodiation process, thus displays highly reversible capacity, long-term durability, along with ultrafast sodium storage capability. The stable reversible capacity of MoS2/NCF-MP reaches 480 mAh g−1 at 0.1 A g−1 after 100 cycles, and undergoes a long cycling life of 300 cycles at 1 A g−1, no visible capacity degradation is observed. More importantly, even under a very high current density of 30 A g−1, the MoS2/NCF-MP can deliver a commendable capacity of 217 mAh g−1, which means the charge/discharge step can be completed within a very short time of 26 s.