Comparative Study of LiNi 0.5 Mn 1.5 O 4 - δ and LiNi 0.5 Mn 1.5 O 4 Cathodes Having Two Crystallographic Structures:  Fd 3 m and P 4 3 32

Nonstoichiometric LiNi0.5Mn1.5O4-δ and stoichiometric LiNi0.5Mn1.5O4 cathodes with two different structures (Fd3̄m and P4332) were synthesized by a molten salt method. Rietveld refinement of the X-ray diffraction (XRD) data and a selected-area electron diffraction (SAED) study confirmed that the face-centered spinel (Fd3̄m) transformed to the primitive simple cubic (P4332) upon additional heating at 700 °C. The LiNi0.5Mn1.5O4-δ cathode having the space group of Fd3̄m showed better electrochemical behaviors than did the LiNi0.5Mn1.5O4 cathode with the space group of P4332, specifically, a lower area-specific impedance (ASI) and a higher discharge capacity during cycling at high rate. XRD and SAED showed that…

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  National Academy of Sciences of Ukraine