Formation and Lithiation of Ferroselite Nanoflowers as High-energy Li-ion Battery Electrodes

Ferroselite (FeSe2) nanoflowers were prepared by a mild hydrothermal method at 170 degrees C with Na2SeSO3 and FeC2O4 as the raw materials, and lithiated through a secondary hydrothermal reaction with Li salt solution. The products were characterized by XRD, FE-SEM, EDS, CV and model battery testing. The results show that the as-prepared FeSe2 nanoflowers composed of uniform nanoplates about 20 nm in thickness and 100 nm in diameter, exhibit high discharge capacity of ca. 431 mAh/g. Notably, the capacity retention rate of FeSe2 nanoflower electrodes is greatly improved from 45% before lithiation to 63% after lithiation through secondary hydrothermal lithiation modification and this improvement of cycling property is confirmed by CV investigation, probably resulting from increase of structure stability and weakening of electrostatic interaction between FeSex layers and Li+ ions in interlayer during the discharge when Li ions occupy the interstitial site of FeSe2 lattice.