Preparation, characterization and electrochemical performance of LiNi xCoyCuzMn2-x-y-zO4 as positive electrodes in lithium rechargeable batteries

Authors

Atef Y. ShenoudaFollow
El Sayed M. El Sayed, Central Metallurgical Research and Development Ins
Hua-Kun Liu, University of WollongongFollow

RIS ID

44822

Publication Details

Shenouda, A. Y., El Sayed, E. M. Liu, H. K. (2011). Preparation, characterization and electrochemical performance of LiNi xCoyCuzMn2-x-y-zO4 as positive electrodes in lithium rechargeable batteries. Journal of New Materials for Electrochemical Systems, 14 (1), 19-26.

Abstract

A series of spinel compounds including LiCu_0.25Co_0.25Ni_0.25Mn_1.25O₄ and LiMn₂O₄ were prepared by the sol–gel method using glycine, ethanol, and ammonia solutions. The structural and magnetic properties were examined by X-ray diffraction, Scanning Electron Microscopy, and electron spin resonance. The prepared powders have spinel-phase cubic structure with space group Fd3m. It is found that the Curie constant “Cp” and the effective magnetic moment “μ_eff” values decrease with the more metal doping. The electrochemical properties were characterized and found to be superior for the LiCu_0.25Co_0.25Ni_0.25Mn_1.25O₄. It was observed that the Warburg impedance coefficient (?w) was 122 Ω.s^-0.5 for LiCu_0.25Co_0.25Ni_0.25Mn_1.25O₄ (sample B), which was lower than the value for LiMn₂O₄ (sample A), 819Ω.s^-0.5. Also, the diffusion coefficient (D) values of the lithium ions diffusing into the bulk electrode materials were calculated. Sample B had a higher “D” value than sample A. The prepared multi-doped lithium manganate spinel material delivered a higher specific discharge capacity of ~150 mAhg^-1 compared to 115 mAhg^-1 for LiMn₂O₄ after 150 cycles.