A critical electrochemical performance descriptor of ferrites as anode materials for Li-ion batteries: Inversion degree

Abstract

In order to understand the essential relationship between the degree of inversion of MFe2O4 and their electrochemical properties as anode materials for Li-ion batteries (LIBs), microspherical MFe2O4 (M = Ni, Co and Zn) nanocomposites were prepared via a facile wet-chemical method. The results showed that all the obtained microspherical nanocomposites are composed of their corresponding nanoparticles with a diameter of about 20 nm. The electrochemical results showed that these hierarchical nanocomposites exhibit excellent properties with high capacities, good cycling stabilities and superior rate capabilities. Moreover, MFe2O4 electrodes at different degree of inversion demonstrated the different Li-ions storage mechanisms. NiFe2O4, at high degree of inversion demonstrated one-step mechanism. CoFe2O4, at medium degree of inversion demonstrated consecutive two-step mechanism. Finally, ZnFe2O4, at low degree of inversion, demonstrated separated multistep mechanism. Therefore, it is reasonable to believe that different degree of inversion can be used as the electrochemical performance descriptor for novel ferrites-based anode materials for high performance LIBs.