Electronic, Structural, and Electrochemical Properties of LiNi_xCu_yMn_2-x-yO₄ (0 < x < 0.5, 0 < y < 0.5) High-Voltage Spinel Materials

Journal Article · Tue Sep 06 00:00:00 EDT 2011 · Chemistry of Materials

DOI:https://doi.org/10.1021/cm200042z· OSTI ID:1018856

Yang, Ming-Che; Xu, Bo; Cheng, Ju-Hsiang; Pan, Chun-Jern; Hwang, Bing-Joe; Meng, Ying S ^[1]

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1. Florida

First principles computation is carried out for investigating the electronic, structural, and electrochemical properties of LiM_1/2Mn_3/2O₄ (M = Ti, V, Cr, Fe, Co, Ni, and Cu). The computation results suggest that doping with Co or Cu can potentially lower Li diffusion barrier as compared to Ni doping. Our experimental research has focused on LiNi_xCu_yMn_2-x-yO₄ (0 < x < 0.5, 0 < y < 0.5), and we found that the amount of Cu will affect the lattice parameters, the cation disorder in the spinel lattice, the particle morphology, as well as the electrochemical properties. Crystal structures, electronic structures, and electrochemical properties of LiNi_xCu_yMn_2-x-6O₄ (0 < x < 0.5, 0 < y < 0.5) are studied by X-ray diffraction (XRD), scanning electron microscopy (SEM), X-ray absorption spectroscopy (XAS), and electrochemical measurements including potentiostatic intermittent titration technique (PITT). With detailed electrochemical measurements and in situ XAS experiments of LiNi_0.25Cu_0.25Mn_1.50O₄, the proposed explanation of the voltage profile by the first principles computation was proven, a second plateau at 4.2 V originates from the oxidation of Cu²⁺ to Cu³⁺, and the plateau at 4.95 V may originate from extra electrons provided by oxygen ions. Although the reversible discharge capacity decreases with increasing Cu amount, optimized composition such as LiCu_0.25Ni_0.25Mn_1.5O₄exhibits high capacities at high rates.

• Research Organization: Argonne National Lab. (ANL), Argonne, IL (United States). Advanced Photon Source (APS)
• Sponsoring Organization: UNIVERSITYDOE - BASIC ENERGY SCIENCES
• OSTI ID: 1018856
• Journal Information: Chemistry of Materials, Vol. 23, Issue (11) ; 06, 2011; ISSN 0897-4756
• Publisher: American Chemical Society (ACS)
• Country of Publication: United States
• Language: ENGLISH

Related Subjects

74 ATOMIC AND MOLECULAR PHYSICS
ABSORPTION SPECTROSCOPY
CAPACITY
CATIONS
CRYSTAL STRUCTURE
DIFFUSION BARRIERS
ELECTRONIC STRUCTURE
ELECTRONS
LATTICE PARAMETERS
MORPHOLOGY
OXIDATION
OXYGEN IONS
SCANNING ELECTRON MICROSCOPY
SPINELS
TITRATION
X-RAY DIFFRACTION