Laminar-protuberant like p-FeS2 rooted in mesoporous carbon sheets as high capacity anode for Na-ion batteries

Iron sulfide (FeS2) serves as tempting anode material for sodium-ion batteries (SIBs) owing to their higher theoretical specific capacity and truncated cost. However, the huge volume expansion during electrochemical cycling lowers the electro-conductivity and restricts their practical usage. In this study, a FeS2/carbon hybrid composite has been prepared through hydrothermal reaction and tested as a negative electrode for SIBs. The morphological analysis presents void betwixt p-FeS2 particles, ensuring structural reliability. X-ray photoelectron spectroscopy and X-ray absorption spectroscopy techniques are executed to examine the chemical environment and oxidation states for discharged/charged FeS2/C. When tested as an anode, the initial sodiation/desodiation capacity was recorded as 679/562 mAh g-1 at a rate of 0.05 C (where 1 C = 447 mA g-1). The rate performance of FeS2/C was evaluated in a range of 0.05-10.0 C where the material delivers a capacity of 319 mAh g-1 at 10.0 C. The FeS2/C composite exhibited an excellent Na storage capacity of 402 mAh g-1 after 200 cycles at 0.05 C with capacity retention and coulombic efficiency of 72% and 99.5%, respectively. The improved adsorption of Na-ions, good rate capacity and cycling stability is promoted from the synergistic interaction among FeS2 par-ticles sited on the conductive sheets of mesoporous carbon matrix. Moreover, mesoporous carbon matrix is deemed responsible for better charge transfer and suppressing volume expansion during insertion/extraction cycles.

Automated summary

In this study, a FeS2/carbon hybrid composite was prepared for sodium-ion batteries (SIBs) as a negative electrode. The FeS2/C composite exhibited excellent structural reliability, sodium storage capacity, and rate performance. The synergistic interaction among FeS2 particles sited on the conductive sheets of mesoporous carbon matrix contributed to the improved adsorption of sodium ions, good rate capacity, and cycling stability.