Flower-like Fe-doped NiSe2/C hybrid spheres fabricated by a glucose-intercalation strategy for enhanced sodium storage properties

Nickel diselenide (NiSe₂), which has a high theoretical capacity, has attracted considerable attention as a promising anode material for sodium-ion batteries (SIBs). Nevertheless, the intrinsically low conductivity, large volume variation, and significant aggregation of NiSe₂ during sodiation/desodiation remain significant obstacles to its application. Herein, we report flower-like Fe-doped NiSe₂/C hybrid spheres (denoted as Fe-NiSe₂/C) fabricated by a glucose intercalation strategy for efficient sodium storage. These Fe-NiSe₂/C hybrid spheres are composed of thin porous carbon nanosheets decorated with Fe-NiSe₂ nanoparticles. In situ introduced carbon nanosheets derived from intercalated glucose accompanied by moderate Fe doping in NiSe₂ nanoparticles can provide accelerated ion/electron transfer kinetics through fast ion channels in the flower-like architecture and intimately contacted interfaces between NiSe₂ and carbon nanosheets as well as maintain structural integrity by alleviating volume variation. Consequently, the optimal anode of the Fe-NiSe₂/C hybrid spheres delivered a high discharge capacity of 415 mAh g⁻¹ at 0.5 A g⁻¹, outstanding rate capability (243 mAh g⁻¹ at 5 A g⁻¹), and significantly enhanced cycling stability (388 mAh g⁻¹ at 1 A g⁻¹ over 200 cycles). This work offers an efficient and valuable strategy for realizing tailored heteroatom doping in transition metal selenides, accompanied by an in situ combination of conductive carbonaceous networks for advanced alkali metal ion batteries.