Investigation of low molecular weight sulfur–limonene polysulfide electrodes in Li–S cells

Abstract

The use of inverse vulcanised copolymeric electrodes have typically provided favourable effects on one the most challenging aspects of Li-S cell chemistry, the capacity retention. Unfortunately, it is not clearly...

The Role of Carbon-Based Cathode Components in Li–S Batteries

“…, and Li 2 S (S K-edge) 12,15,16 -Analyte can be amorphous -Sensitivity to variations in oxidation states -(XAS) sensitivity to variations in molecular geometry -inherent metastability of polysulfides in isolation can complicate deconvolution of some measured spectra -(XAS) self-absorption effects from large particle sizes and high concentrations of the photo-absorber can cause significant distortions to measured spectra 1 H, 13 C, 7 Li Solidstate NMR -Identification of amorphous lithium environments via 7 Li NMR 12,17 -Hydrocarbon environments can be investigated using 1 H-13 C crosspolarization methods; abundant 1 H nuclei yield high signal to noise but often broad and featureless peaks due to strong 1 H-1 H coupling. This isotopic abundance however can be used to enhance sensitivity of neighboring rare 13 C that can offer higher resolution between different chemical environments -Evolution of copolymeric structure over cycling via 13 C-1 H NMR [17][18][19] -Analyte can be amorphous -Correlation between copolymer and lithium moieties via 1 H- 13 C HETCOR and 1 H- 7 Li EXSY NMR [18][19][20] -Inherent metastability of polysulfides in isolation that complicate deconvolution of measured spectra -Narrow range of 7 Li chemical shifts and alternatively poor signal to noise in 6 Li NMR techniques used, the information they provide and the contribution to the current understanding of these materials.…”