Achieving high capacity and rate capability in layered lithium transition metal oxide cathodes for lithium-ion batteries

Title
Achieving high capacity and rate capability in layered lithium transition metal oxide cathodes for lithium-ion batteries
Authors
조병원오시형정경윤굴람 알리노재교안주현디키 수산토김종학
Keywords
Composition; High capacity; Rate capability; Layered transition metal oxide; In situ X-ray diffraction; Single-phase reaction
Issue Date
2017-08
Publisher
Journal of power sources
Citation
VOL 360-584
Abstract
In this study, we target to find a new composition for a layered mixed metal oxide, which has a high structural stability and a good electrochemical performance. Our strategy is to alter the transition metal composition focusing on the relative amounts of redox active Ni and Co to the inactive Mn, based on highly-stabilized LiNi1/3Co1/3Mn1/3O2. X-ray absorption near-edge structure and X-ray diffraction analyses show that the degree of cation disorder decreases on increasing the ratio of Ni and Co to Mn, by the presence of Ni3+, suggesting that slightly higher Ni and Co contents lead to improved structural stability. Electrochemical studies demonstrate that LiNi0.4Co0.4Mn0.2O2 cathodes exhibit considerable improvements in both the reversible capacity and the rate capabilities at a voltage range of 2.5– 4.6 V. In situ XRD measurements reveal that LiNi0.4Co0.4Mn0.2O2 maintains a single-phase and undergoes lesser structural variations compared to controlled compositions during a delithiation process up to 4.6 V, while achieving a high reversible capacity over 200 mAh g− 1. As a result, LiNi0.4Co0.4Mn0.2O2 experiences fewer structural degradations during electrochemical cycling, which explains the excellent long-term cycling performance.
URI
http://pubs.kist.re.kr/handle/201004/65892
ISSN
0378-7753
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KIST Publication > Article
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