Understanding the nature of absorption/adsorption in nanoporous polysulfide

sorbents for the Li-S battery

Scott Evers, Taeeun Yim and Linda F. Nazar*

Department of Chemistry, University of Waterloo, 200 University Avenue West, Waterloo,

Ontario N2L 3G1, Canada

* lfnazar@uwaterloo.ca

Supplementary FTIR and Raman Spectra

To clarify whether β-TiO2 and γ-TiO2 interacts with LiPS via physical/chemical adsorption as

seen with α-TiO2 in Figure 6, we probed the bonding interaction between both titanias and sulfur

using FTIR and Raman spectroscopy. The FTIR spectrum of β-TiO2/Li2S4 (Figure S1a, bottom)

and γ-TiO2/Li2S4 (Figure S1b, bottom) do not show any discernible new peaks corresponding to

interactions between sulfur and titania (i.e. S-Ti-O) as seen in Figure 6a for α-TiO2. In this case

the Raman spectra for β-TiO2 is more definitive (Figure S1c). There are two peaks at ~395 cm-1

and 510 cm-1

for neat β-TiO2 and when Li2S4 is synthesized in the presence of β-TiO2 these

peaks do not shift (as indicated by the dotted red reference line). In the case of γ-TiO2, the

Raman spectra (Figure S1d) is more difficult to interpret and there may be a peak shift which

could indicate interactions between sulfur and titania, but the sulfur signal from Li2S4 is too

broad and strong and may envelop the titania peak. In any case, even if there is some surface

interaction, the poor electrochemical performance of γ-TiO2 proves that surface adsorption is not

singularly sufficient; there must be a porous architecture present.

Figure S1: (a) FTIR spectra of neat β-TiO2 (top, purple) and neat β-TiO2/Li2S4 (bottom, black);

(b) FTIR spectra of neat γ-TiO2 (top, red) and neat γ-TiO2/Li2S4 (bottom, black); (c) Raman

spectra of neat β-TiO2 (top, purple) and neat β-TiO2/Li2S4 (bottom, black); (d) Raman spectra of

neat γ-TiO2 (top, red) and neat γ-TiO2/Li2S4 (bottom, black)