Pomegranate-like mesoporous microspheres assembled by N-doped carbon coated Fe1−xS nanocrystals for high-performance lithium storage

Uniform pomegranate-like mesoporous Fe1−xS@N-doped carbon microspheres (Fe1−xS@NC) organized by ultrafine Fe1−xS nanocrystal subunits (diameter∼11.9 nm) were prepared via a facile solvothermal process and subsequent sulfidation. In such pomegranate-like mesoporous Fe1−xS@NC, the ultrafine Fe1−xS nanocrystal subunits were embedded within N-doped carbon outer shell, not only shortening Li+/electron diffusion pathways for electrochemical reaction and increasing the electrical conductivity to boost rate capability, but also efficiently preventing ultrafine Fe1−xS subunits from self-accumulation to prolong their cycle life during the electrochemical reaction. Correspondingly, the pomegranate-like Fe1−xS@NC composites manifested excellent cycling stability of 689.8 mAh g−1 after 150 cycles, a high discharge capacity of 1358.3 mAh g−1 at 0.1 A g−1, and superior rate capability of 666.0 mAh g−1 at 5 A g−1 as an anode material for LIBs.