Preparation and Evaluation of Fe ₇ S ₈ /NCNs Anode Materials for Lithium‐Ion Batteries

ABSTRACT Fe 7 S 8 has obtained significant attention due to its high theoretical capacity and low cost for lithium ion batteries. However, its practical application is hindered by poor intrinsic conductivity and severe volume expansion during cycling. To address these critical issues, we have successfully fabricated a Fe 7 S 8 /NCMs composite by anchoring Fe 7 S 8 nanoparticles into nitrogen‐doped carbon nanospheres (NCNs) via a facile hydrothermal method followed by calcination. The incorporation of NCNs preserves the structural integrity of the electrode material and enhances its electrical conductivity. Moreover, the Fe 7 S 8 nanoparticles are uniformly dispersed in the surface of the carbon microspheres, reducing agglomeration and effectively alleviating volume expansion, thereby maintaining the structural stability of the electrode material. The Fe 7 S 8 /NCNs composite exhibits excellent cycling stability (with an initial discharge specific capacity of 1142.6 mAh g −1 at 0.1 A g −1 and a high specific capacity of 829.3 mAh g −1 after 150 cycles) and superior rate performance (a reversible capacity of 603.5 mAh g −1 when the current density is reduced from 3 A g −1 back to the initial 0.1 A g −1 ).