Fig. 6

Evolution of particle morphology of the PAN-coated MYS-CuO cyclized at 280 °C (P-280-MYS) used as the cathode during charging-discharging. a Voltage profile of the P-280-MYS cathode at a current density of 10 mA g^− 1 during the first charge-discharge cycle. Surface morphology of the P-280-MYS cathode at depths of discharge (DODs) of b 25%, c 50%, and d 100% and states of charge (SOCs) of e 25%, f 50%, and g 100%. h Schematic of the overall morphological evolution of the active material of the P-280-MYS cathode during the first charge-discharge cycle