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Title: Cathode of LiMg{sub y}Mn{sub 2{minus}y}O{sub 4} and LiMg{sub y}Mn{sub 2{minus}y}O{sub 4{minus}{delta}} spinel phases for lithium secondary batteries

Abstract

To improve the cycle performance of LiMn{sub 2}O{sub 4} (Fd{bar 3}m) as the cathode of 4 V class lithium secondary batteries, the cathode properties of the quaternary cubic spinel phases LiMg{sub y}Mn{sub 2{minus}y}O{sub 4} synthesized at 750 C were examined. Although the cycle performance of the LiMg{sub y}Mn{sub 2{minus}y}O{sub 4} was improved by the substitution of Mg{sup 2+} for Mn{sup 3+} in the octahedral sites, the first discharge capacity was reduced considerably compared with that of the parent LiMn{sub 2}O{sub 4}. In order to compensate for the theoretical capacity reduction in LiMg{sub 1/6}Mn{sub 11/6}O{sub 4}, nonstoichiometric spinel oxides LiMg{sub 1/6}Mn{sub 11/6}O{sub 4{minus}{delta}} were prepared under controlled oxygen partial pressures at 750 C. The single-phase region of {delta} in LiMg{sub 1/6}Mn{sub 11/6}O{sub 4{minus}{delta}} was 0 {le} {delta} {le} 0.04, which was larger than that of parent LiMn{sub 2}O{sub 4} (0 {le} {delta} < 0.018) in previous work. From density data, a metal excess model (Li){sub 8a}[Li{sub {delta}/(4{minus}{delta})}Mg{sub {delta}/6(4{minus}{delta})}Mn{sub 11{delta}/6(4{minus}{delta})}]{sub 16c}[Mg{sub 1/6}Mn{sub 11/6}]{sub 16d}O{sub 4} was proposed as the defect structure in the LiMg{sub 1/6}Mn{sub 11/6}O{sub 4{minus}{delta}}. The chemical diffusion coefficient of lithium ion for nonstoichiometric LiMg{sub 1/6}Mn{sub 11/6}O{sub 4{minus}{delta}} was smaller than that for the stoichiometric LiMg{sub 1/6}Mn{sub 11/6}O{sub 4}. Thismore » also supported the metal excess model, because excess metals in 16c sites prevented an easier diffusion of lithium in the 8a-16c-8a diffusion path.« less

Authors:
; ;  [1]
  1. Tokyo Inst. of Tech. (Japan). Dept. of Chemical Engineering
Publication Date:
OSTI Identifier:
345323
Resource Type:
Journal Article
Journal Name:
Journal of the Electrochemical Society
Additional Journal Information:
Journal Volume: 146; Journal Issue: 4; Other Information: PBD: Apr 1999
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; 25 ENERGY STORAGE; METAL-NONMETAL BATTERIES; LITHIUM; CATHODES; LITHIUM OXIDES; MAGNESIUM OXIDES; MANGANESE OXIDES; PHASE STUDIES; PERFORMANCE

Citation Formats

Hayashi, N, Ikuta, H, and Wakihara, M. Cathode of LiMg{sub y}Mn{sub 2{minus}y}O{sub 4} and LiMg{sub y}Mn{sub 2{minus}y}O{sub 4{minus}{delta}} spinel phases for lithium secondary batteries. United States: N. p., 1999. Web. doi:10.1149/1.1391769.
Hayashi, N, Ikuta, H, & Wakihara, M. Cathode of LiMg{sub y}Mn{sub 2{minus}y}O{sub 4} and LiMg{sub y}Mn{sub 2{minus}y}O{sub 4{minus}{delta}} spinel phases for lithium secondary batteries. United States. doi:10.1149/1.1391769.
Hayashi, N, Ikuta, H, and Wakihara, M. Thu . "Cathode of LiMg{sub y}Mn{sub 2{minus}y}O{sub 4} and LiMg{sub y}Mn{sub 2{minus}y}O{sub 4{minus}{delta}} spinel phases for lithium secondary batteries". United States. doi:10.1149/1.1391769.
@article{osti_345323,
title = {Cathode of LiMg{sub y}Mn{sub 2{minus}y}O{sub 4} and LiMg{sub y}Mn{sub 2{minus}y}O{sub 4{minus}{delta}} spinel phases for lithium secondary batteries},
author = {Hayashi, N and Ikuta, H and Wakihara, M},
abstractNote = {To improve the cycle performance of LiMn{sub 2}O{sub 4} (Fd{bar 3}m) as the cathode of 4 V class lithium secondary batteries, the cathode properties of the quaternary cubic spinel phases LiMg{sub y}Mn{sub 2{minus}y}O{sub 4} synthesized at 750 C were examined. Although the cycle performance of the LiMg{sub y}Mn{sub 2{minus}y}O{sub 4} was improved by the substitution of Mg{sup 2+} for Mn{sup 3+} in the octahedral sites, the first discharge capacity was reduced considerably compared with that of the parent LiMn{sub 2}O{sub 4}. In order to compensate for the theoretical capacity reduction in LiMg{sub 1/6}Mn{sub 11/6}O{sub 4}, nonstoichiometric spinel oxides LiMg{sub 1/6}Mn{sub 11/6}O{sub 4{minus}{delta}} were prepared under controlled oxygen partial pressures at 750 C. The single-phase region of {delta} in LiMg{sub 1/6}Mn{sub 11/6}O{sub 4{minus}{delta}} was 0 {le} {delta} {le} 0.04, which was larger than that of parent LiMn{sub 2}O{sub 4} (0 {le} {delta} < 0.018) in previous work. From density data, a metal excess model (Li){sub 8a}[Li{sub {delta}/(4{minus}{delta})}Mg{sub {delta}/6(4{minus}{delta})}Mn{sub 11{delta}/6(4{minus}{delta})}]{sub 16c}[Mg{sub 1/6}Mn{sub 11/6}]{sub 16d}O{sub 4} was proposed as the defect structure in the LiMg{sub 1/6}Mn{sub 11/6}O{sub 4{minus}{delta}}. The chemical diffusion coefficient of lithium ion for nonstoichiometric LiMg{sub 1/6}Mn{sub 11/6}O{sub 4{minus}{delta}} was smaller than that for the stoichiometric LiMg{sub 1/6}Mn{sub 11/6}O{sub 4}. This also supported the metal excess model, because excess metals in 16c sites prevented an easier diffusion of lithium in the 8a-16c-8a diffusion path.},
doi = {10.1149/1.1391769},
journal = {Journal of the Electrochemical Society},
number = 4,
volume = 146,
place = {United States},
year = {1999},
month = {4}
}