Fig. 4From: Carbon- and Binder-Free NiCo2O4 Nanoneedle Array Electrode for Sodium-Ion Batteries: Electrochemical Performance and Insight into Sodium Storage ReactionDischarge–charge profiles of NCO-NNA electrodes in a Li and b Na half-cells measured at a current density of 50 mA g−1 during the initial 10 cyclesBack to article page