Research Information System
International Journal Of Energy Research, vol.11, no.1, pp.1-13, 2021 (SCI-Expanded)
Na0.67(Mn0.5Fe0.5)1-xCuxO2 powders (where x = 0, 0.05, 0.1, 0.2, and 0.3) were
produced by quenching at 900C, and the structural features of the powders
were studied in detail. It was found that the undoped and Cu-substituted for
(x ≤ 0.2) powders had no impurity phases in the structure. Furthermore, the
lattice volume calculated by the GSAS-II open-source program decreased with
increasing Cu content, and it is suggested that Cu ions have a 3+ valence state
in the samples. The cycling voltammetry of the cells is very similar to each
other. The constant current charge/discharge cycling measurements were performed
for up to 100 cycles, and the best performance was observed for x = 0.2
Cu substitution in Na0.67(Mn0.5Fe0.5)1-xCuxO2. The best capacity value was
obtained as 182.3 mAh/g at the C/10 rate for x = 0.2 Cu substitution. The
cycling measurements at 50C exhibit worse capacity fade when compared to
the measurements performed under ambient conditions. The in situ infrared
thermal imaging measurements for the cell that had the highest performance
in this study were performed for a constant voltage of 4.3 V for charging and
1.5 V for discharging of the cell. The ohmic heat was calculated from chronoamperometry
measurements, and the heat generation was fitted with the quadratic
term in the system.