Fig. 5: Electrochemical performances of air-exposed Na0.67MnO2 and Na0.67Ni0.33Mn0.67O2.
From: The stability of P2-layered sodium transition metal oxides in ambient atmospheres
a The cycling performance of pristine Na0.67MnO2, the inset shows the charge-discharge curve at the 2nd cycle. b The charge-discharge curves and cycling stability of totally hydrated Na0.67MnO2 sample. c–f The electrochemical performances within the voltage range of 2.0–4.0 V of three Na0.67Ni0.33Mn0.67O2 samples (pristine Na0.67Ni0.33Mn0.67O2, Na0.67Ni0.33Mn0.67O2 samples immersed in water for 20 days and exposed in RH 93% + CO2 for 3 days). c The initial charge-discharge curves at 12 mA g−1. d The cycling stability of the three samples at 120 mA g−1 (after two formation cycles at 12 mA g−1). e The comparison of the impedance responses at the 1st and 100th cycles with frequency varied from 100 kHz to 10 mHz. f The rate capability of three samples at the voltage range of 2.0–4.0 V.
