fig3

Figure 3. (A) Galvanostatic Na plating profiles on the bare Cu and Bi₂S₃@Cu substrates at 1 mA cm^-2; (B) Comparison of CEs upon Na plating/stripping cycling on the Cu and Bi₂S₃@Cu substrates at 5 mA cm^-2 and 1 mAh cm^-2; (C and D) Voltage-capacity curves of sodium plating/stripping processes on Bi₂S₃@Cu substrate (C) and Cu substrate (D) at 5 mA cm^-2; (E-G) Voltage-time profiles of symmetric cells of Na/Bi₂S₃@Cu and Na@Cu electrodes at (E) 2 mA cm^-2 and 2 mAh cm^-2, (F) 3 mA cm^-2 and 1 mAh cm^-2, and (G) 5 mA cm^-2 and 5 mAh cm^-2, with insets displaying magnified views of selected cycles; (H) Rate performance of Na/Bi₂S₃@Cu symmetric cells tested at current densities ranging from 2 mA cm^-2 to 10 mA cm^-2 with a fixed capacity of 1 mAh cm^-2; (I) Nyquist plots of Na/Bi₂S₃@Cu symmetric cells after different cycles. CEs: Coulombic efficiencies.