fig4

Figure 4. XPS analysis of the SEI layer. (A) XPS survey spectra of the Mo₂Ti₂C₃T_x, Mo₂TiC₂T_x, Mo₂CT_x, and the bare Cu. (B) Atomic concentration of Li, F, C, and O in the SEI layer. (C) Li 1s XPS spectra. (D) Relative percentage of different components in the SEI layer of the Mo₂Ti₂C₃T_x, Mo₂TiC₂T_x, Mo₂CT_x, and bare Cu electrodes.