Doubling the Capacity of Lithium Manganese Oxide Spinel by a Flexible Skinny Graphitic Layer |
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Authors: | Dr. Hyun Kuk Noh Han‐Saem Park Prof. Hu Young Jeong Prof. Sang Uck Lee Prof. Hyun‐Kon Song |
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Affiliation: | 1. School of Energy and Chemical Engineering, UNIST, Ulsan, 689‐798 (Korea);2. UNIST Central Research Facilities (UCRF), UNIST, Ulsan 689‐798 (Korea);3. Department of Chemistry, University of Ulsan, Ulsan 680‐749 (Korea) |
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Abstract: | By coating nanoparticular lithium manganese oxide (LMO) spinel with a few layers of graphitic basal planes, the capacity of the material reached up to 220 mA h g?1 at a cutoff voltage of 2.5 V. The graphitic layers 1) provided a facile electron‐transfer highway without hindering ion access and, more interestingly, 2) stabilized the structural distortion at the 3 V region reaction. The gain was won by a simple method in which microsized LMO was ball‐milled in the presence of graphite with high energy. Vibratory ball milling pulverized the LMO into the nanoscale, exfoliated graphite of less than 10 layers and combined them together with an extremely intimate contact. Ab initio calculations show that the intrinsically very low electrical conductivity of the tetragonal phase of the LMO is responsible for the poor electrochemical performance in the 3 V region and could be overcome by the graphitic skin strategy proposed. |
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Keywords: | ab initio calculations graphitic layers lithium‐ion batteries lithium manganese oxide spinel |
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