Structure and electrochemical performance of hollow microspheres of LiFexNi1/3−xCo1/3Mn1/3O2 (0.000 ≤ x ≤ 0.267) as cathodes for lithium-ion batteries

Abstract

LiFe_xNi_1/3−xCo_1/3Mn_1/3O₂ (0.000 ≤ x ≤ 0.267) hollow microspheres have been synthesized by an approach using manganese carbonate microspheres as self-templates and substituting stoichiometric iron for nickel. XRD analysis shows that the obtained materials have a layered α-NaFeO₂ structure (rhombohedral lattice, Rm space group). With the addition of iron, the lattice parameters of these samples increase in the low-x region (x ≤ 0.133) and reach their maximum values at x = 0.133. The behavior of the lattice parameters is consistent with their specific capacities at 0.1 C rate, which means moderate substitution of iron can enhance the performance. Meanwhile, the iron substitution destroys the hollow microspheres and results in microsphere aggregation, which can be found from their surface morphologies using the SEM analysis. Compared with the others, when x is equal to 0.133, the sample exhibits a relatively superior electrochemical performance.