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|
| Type |
Poster Presentation |
| Area |
Material Chemistry |
| Room No. |
Exhibition Hall 2 |
| Time |
4월 19일 (금요일) 11:00~12:30 |
| Code |
MAT.P-447 |
| Subject |
Calcium-Doping for Structure Stabilization of Sodium Transition Metal Oxide Cathodes in Sodium Ion Batteries |
| Authors |
Su Cheol Han, Myoungho Pyo*
Department of Printed Electronics Engineering, Suncheon National University, Korea
|
| Abstract |
P2-Na0.67Ni0.33Mn0.67O2(NNMO), which has a layered structure, is a promising cathode material for sodium ion batteries. The stack TM slabs in a layered structure of NNMO, are composited of edge and face-shared (TM)O6 octahedra, forming metal-occupied Octahedral sites and empty tetrahedral sites. The prismatic sites in Na slabs are also occupied by Na+ ions, which are sandwiched by edge and face-sharing with TM slabs. In this work, P2-Na0.67-2xNi0.33Mn0.67O2 (0 < x ≤ 0.1) was synthesized by incorporating Ca2+ into NaO6 layer of NNMO. Both the significant difference in ionic radii between Ca2+ (1.0Å) and Ni2+ (0.69 Å), Mn3+ (0.58 Å) and the reduction of Na+ content allowed the preparation of phase-pure and cation-mixing-free (i.e., absence of Ca2+ in transition metal oxide layers) Na0.67-2xCaxNi0.33Mn0.67O2 up to x = 0.05. It is expected that, while no noticeable change is observed in a dimension of (TM)O6 octahedron, NaO6 layers continuously shrink as the increase of Ca2+ content. The latter effect was expected to prevent the structural change (Na+-vacancy ordering) during repeated charge-discharge, eventually contributing to the improvement of capacity retention. Preliminary study indicated that, while pristine NNMO. showed a continuous decrease in discharge capacity, Na0.57Ca0.05Ni0.33Mn0.67O2 maintained a significant fraction of an initial capacity with a small capacity fading during 40 cycles. |
| E-mail |
sucheol@sunchon.ac.kr |
|
123rd General Meeting of the KCS