Yolk–Shell MoS₂ Nanosphere-Doped Electron-Rich Iron Heteroatoms for Ultralong Lifespan Na-Ion Batteries

Abstract

Molybdenum disulfide (MoS 2 ) has been extensively studied as an anode for sodium-ion batteries owing to its large theoretical specific capacity and steady crystal texture. Nevertheless, the unsatisfactory rate capability and short cycling lifespan of MoS 2 derived from its inferior electrical conductivity and extensive volume variation among Na + insertion and extraction have greatly impeded its practical exploitation. Hence, we proposed an electron coupling strategy with the rational incorporation of iron heteroatoms in a novel yolk−shell MoS 2 nanostructure (FMS@C) through an advanced micelle-confined microemulsion technology. In this configuration, the doping of electron-rich Fe heteroatoms breaks the long-range ordered texture of pristine MoS 2 with extensively activated electronic structures, thus enabling accelerated mass transfer and charge diffusion. Meanwhile, the novel yolk−shell nanoarchitecture with enough inner room can efficiently accommodate the volume variation during repeated charge/discharge cycles, thus favoring the high stability of the structure. Consequently, the prepared FMS@C anode delivers superior rate capability and impressive reversible capacity retention, and it can achieve 201.5 mA h −1 after 5500 cycles at 5 A g −1 with a low capacity decay of 0.0057% per cycle. Accordingly, this work opens up a brilliant way to improve the performance of metal sulfur compounds as advanced energy storage electrodes.