[9p-W351-1~12] 9.4 Thermoelectric conversion

[9p-W351-3] x-dependence of Temperature Coefficient of Redox Potential of P2-Na_xCoO₂

〇Yuya Fukuzumi¹, Yoyo Hinuma², Yutaka Moritomo^1,3,4 (1.Grad. Sch. Pure and Appl. Sci., Univ. Tsukuba, 2.Ctr. Frontier Sci., Chiba Univ., 3.Fac. Pure and Appl. Sci., Univ. Tsukuba, 4.TREMS, Univ. Tsukuba)

Keywords:entropy, transition metal oxide, tertiary battery

Temperature coefficient of redox potential (α = ∂V/∂T, where V and T are redox potential and temperature, respectively) is a significant material parameter, which is important to develop tertiary batteries. In this study, α of P2-Na_xCoO₂ was measured against sodium concentration (x). The x-dependence of α was not reproduced even quantitatively by our DFT calculations using a phase separation (PS) model. In the presentation, we discuss the reason for the mismatch of the PS model and consider an effect of configurational entropy of sodium ions.