fig4

Figure 4. Performance of the Li||Li and Li||Cu cells with PP, PEI and PEI-EDA separators. Constant current cycle curves of Li||Li symmetric cells at 0.2 mA·cm^-2, 0.2 mAh·cm^-2 (A), 1 mA·cm^-2, 1 mAh·cm^-2 (B), and at stepped-increased current densities from 0.5 to 5 mA·cm^-2 (C); (D) EIS spectra of the Li||Li cells after 50 cycles; (E) Galvanostatic voltage profiles of Li deposition; (F) Performance of the Li||Cu cells; (G) Charge and discharge profiles of the Li||Cu cells; (H-J) SEM image of the Li-metal on Cu foil after five cycles at the density current of 0.5 mA·cm^-2: (H) PP, (I) PEI, (J) PEI-EDA. PEI-EDA: Ethylenediamine grafting polyetherimide; PEI: polyetherimide; PP: polypropylene; SEM: scanning electron microscopy; EIS: electrochemical impedance spectroscopy.