Figure 2. Raman spectra for bulk and thin-film MoS₂ samples before lithiation.

Spectra obtained at (a) low frequencies and (b) high frequencies. The y-axis is the signal intensity normalized by laser power (S/P) in the unit of counts per second per milliwatt (cps mW⁻¹). The bulk spectrum is shifted up by 50 cps mW⁻¹. Raman spectra for bulk Li_xMoS₂ samples at different degrees of lithiation (x=0, 0.34 and 0.68) at (c) low frequencies, (d) high frequencies. The x=0.34 and x=0 spectra are shifted up by 65 and 130 cps mW⁻¹, respectively.