Enhanced energy storage performance of nanocrystalline Sm-doped CoFe2O4 as an effective anode material for Li-ion battery applications

A simple modified combustion method was demonstrated in the development of cobalt ferrite (CoFe 2 O 4 ) and samarium (Sm)-doped CoFe 2 O 4 nanostructures. The Sm 3+ -doped CoFe 2 O 4 can significantly affect their crystallite size, lattice parameter, and electrical and electrochemical properties. The powder X-ray diffraction analysis revealed the formation of cubic spinel CoFe 2 O 4 . The structural coordination of pristine and Sm 3+ -doped CoFe 2 O 4 samples was confirmed by Raman and Fourier transform infrared spectroscopy analyses and also peak positions of Sm 3+ -doped CoFe 2 O 4 sample shifted toward lower wavenumber, which may be due to the cell expansion resulting from Sm 3+ doping in CoFe 2 O 4 structure. In addition to above, X-ray photoelectron spectroscopy results clearly demonstrated the doping of Sm 3+ into CoFe 2 O 4 crystal lattice. The electrical conductivity of Sm 3+ -doped CoFe 2 O 4 is one order of magnitude higher than that of pristine CoF 2 O 4 . The prepared pristine and Sm 3+ -doped CoFe 2 O 4 samples were investigated as an anode material for lithium (Li)-ion batteries. The Sm 3+ -doped CoFe 2 O 4 anode showed a better reversibility and rate performance than the pristine CoFe 2 O 4 anode. Also, the Sm 3+ -doped CoFe 2 O 4 electrode exhibited a stable cycling performance with a discharge capacity of 800 mAh g −1 after 150 cycles at 0.1 C and delivered a discharge capacity of 778 mAh g −1 after 400 cycles at 200 mA g −1 . The observed high electrochemical performance of Sm 3+ -doped CoFe 2 O 4 electrode may be attributed to its improved structural stability and enhanced oxidation reaction which maintain the number of Li ions involved in the charge-discharge process.