Fig. 3: Morphologies and residual composition of cycled Cu in Li | |Cu half cells.
a Potential-capacity profiles of the Li stripping process of Li | |Cu cells through CC plating protocol. b Potential-capacity profiles of the Li stripping process of Li | |Cu cells through MPC plating protocol. c Front and d Cross-sectional SEM images of the Cu foil in Li | |Cu half-cell after being cycled 50 times through CC protocol (3 mAh cm-2, 3 h). e Front and f Cross-sectional SEM images of the Cu foil in Li | |Cu half-cell after being cycled 50 times through MPC protocol (3 mAh cm-2, 3 h). XPS depth profiles for the carbon (C)1 s spectra of the cycled Cu foil after 50 times through g CC and h MPC protocols, respectively. XPS depth profiles for the oxygen (O)1 s spectra of the cycled Cu foil after 50 times through i CC and j MPC protocols, respectively. It is worth noting that for the CC protocol, cycled Cu foil in Li | |Cu half-cell, the Li metal negative electrode was both plated and stripped via CC current, while for the MPC protocol, cycled Cu foil in Li | |Cu half-cell, the Li metal negative electrode was plated via MPC current and stripped via CC current. The electrolyte used here is 1 M LiTFSI in DOL/DME (v/v, 1/1) with 1 wt% LiNO3. Scale bar: c, d, e, f, 50 μm.
