[18p-223-1~17] 6.3 Oxide electronics

△ [18p-223-1] Iron Content (x) Dependence of Local Structure of O3-NaCo_1-xFe_xO₂

〇(M1)Toshiaki Moriya¹, Hideharu Niwa^1,2,3, Yutaka Moritomo^1,2,3 (1.Grad. Sch. Pure and Appl. Sci., Univ. Tsukuba, 2.Fac. Pure and Appl. Sci., Univ. Tsukuba, 3.TREMS, Univ. Tsukuba)

Keywords:batteries, synchrotron Radiation

NaMO₂ (M is a transition metal)is a promising candidate as positive electrode material for sodium-ion batteries. The chemical substitution of M is an effective way to improve the electrochemical performance. Here, we systematically investigated the interatomic distance around Fe in O3-NaCo_1-xFe_xO₂ (0.001 ≤ x ≤ 0.05) by EXAFS (Extended X-ray Absorption Fine Structure). By comparing the experimental values of Fe-M bond length (d_Fe-M) and calculated values based on homogeneous dispersion of Fe, significant differences are observed at x ≥ 0.05. It suggests an aggregation of Fe-O-Fe moiety at x ≥ 0.05.