fig3

Figure 3. (A) The first cycle of CV profiles for batteries with different catalysts at a scan rate of 0.1 mV s^-1; (B) Tafel slopes derived from the CV profiles in (A); (C) Tafel slopes of Ni-CoTe, CoTe, and Gr derived from three CV cycles. The error bars represent the standard deviation (cycle-to-cycle variation) of the Tafel slopes calculated from three consecutive CV cycles; (D-F) Potentiostatic discharge profiles at 2.05 V; (G) Temperature-dependent EIS spectra of the Ni-CoTe cell at 2.3 V; (H) Corresponding Arrhenius plots derived from (G); (I) Discharge activation barriers of Ni-CoTe and CoTe cells calculated from (H). EIS: Electrochemical impedance spectroscopy; CV: cyclic voltammetry.