Fe₂O₃ Nanoparticles on Hard Carbon as Anode of Sodium-Ion Batteries

Hard carbon is a commonly used anode material for sodium-ion batteries (SIBs) due to its high cycling stability. However, its specific capacity is limited due to its intercalation and de-intercalation mechanism. On the contrary, metal oxide has a higher specific capacity due to its conversation mechanism. However, its electric conductivity is low. In this work, a strategy of coating iron oxide (Fe 2 O[Formula: see text] nanoparticles on the surface of hard carbon is developed to enhance the electrochemical performance of SIB anodes. Composites with different contents of Fe 2 O 3 are synthesized, and their morphology and electrochemical performance are characterized. The results show that the increase of Fe 2 O 3 in composite can obviously increase the capacity of composite. However, the cycling stability is decreased. Composite with 38% Fe 2 O 3 exhibits high reversible specific capacity (413.7[Formula: see text]mAh[Formula: see text]g[Formula: see text] at 100[Formula: see text]mA[Formula: see text]g[Formula: see text], high rate performance (182.1[Formula: see text]mAh[Formula: see text]g[Formula: see text] at 5[Formula: see text]A[Formula: see text]g[Formula: see text], and acceptable cycling stability (333.8[Formula: see text]mAh[Formula: see text]g[Formula: see text] after 100 cycles at 100[Formula: see text]mA[Formula: see text]g[Formula: see text]. GCD curves after different cycles are compared, and the possible reason for capacity decay is suggested.