Figure 5.

(a) PXRD pattern of 2D α-Ge anodes after the cycling process (blue line), simulated Li₂CO₃ (purple line), and simulated Li₂O (blue line). Black triangles are assigned to Ge-crystalline, purple squares are assigned to Li₂CO₃, blue squares are assigned to Li₂O, orange squares are assigned to VGCF, and green squares are assigned to Cu. (b) Raman spectrum of 2D α-Ge after the cycling process. Raman spectrum measurement (black line), deconvoluted contributions of crystalline α-Ge at 298 cm⁻¹ (green line), amorphous Ge at 275 cm⁻¹ (orange line), and cumulative plot of both contributions (purple), laser power of 1.75 mW. (c) Ge 3d and O 2s XPS peaks (hν = 1253.6 eV) for 2D α-Ge anode after the cycling process. Experimental data (dotted line) and resulting fit (thick continuous lines). Thin lines correspond to the different contributions and dashed lines to the spin-orbit splitting of Ge 3d.