Figure 8.

Discharge Process, Synthesis Strategies, and Morphological Characterization

(A) Before discharge: the black area represents carbon with pores infiltrated by sulfur and gray particles on the cube surface are SBA-15.

(B) Discharge to 2.15 V: the green-colored area denotes polysulfide ions (S_n²⁻, 3 ≤ n ≤ 8), which are “concentrated” in the SBA-15.

(C) Discharge to 1.5 V: polysulfide ions diffuse out of SBA-15 platelets and are further reduced into solid sulfides (Li₂S/Li₂S₂) within the silica colloidal monolith (SCM) carbon framework. Reprinted with permission from (Ji et al., 2011c). Copyright 2011, Nature Publishing Group.

(D) Schematic of the synthetic process that involves coating of sulfur nanoparticles with TiO₂ to form sulfur-TiO₂ core-shell nanostructures, followed by partial dissolution of sulfur in toluene to achieve the yolk-shell morphology.

(E and F) (E) Scanning electron micrograph and (F) TEM images of as-synthesized sulfur-TiO₂ yolk-shell nanostructures. (E) Scale bar, 2 μm. (F) Scale bar, 1 μm. Through large-ensemble measurements, the average nanoparticle size and TiO₂ shell thickness were determined to be 800 and 15 nm, respectively. Reprinted with permission from (Seh et al., 2013). Copyright 2013, Nature Publishing Group.