Organosulfur/Conducting Polymer Composite Cathodes

Abstract

The dimercaptan 2,5-dimercapto-1,3,4-thiadiazole ͑DMcT͒ has been employed as a component in secondary lithium battery cathodes. However, spectroscopic studies of its behavior have been impeded by general uncertainty regarding its vibrational band character. The purpose of this study is to provide a spectroscopic basis for the unambiguous determination of protonation and oxidation state of DMcT. The first part of this paper is concerned with structural and spectroscopic assignment of DMcT and some derivatives. Several structural and spectroscopic assignments are intrinsically interesting, including ͑i͒ the suggestion that the thioamide-containing compounds adopt the thione tautomer structure whenever the opposite nitrogen is unsubstituted and ͑ii͒ assignment of an A 1 ring mode for the first time for these compounds. The second part of this paper uses that resource to examine the in situ Raman spectroelectrochemistry of DMcT in a nonaqueous solvent. The results confirm, in part, the redox wave assignments made previously in the literature. Specifically, Raman spectroelectrochemistry of solutions of DMcT and the lithium salt of its first conjugate base ͑LiDMcT͒ show that at ca. 0.8 V LiDMcT is oxidized while DMcT is not oxidized, and that at ϩ1.9 V both species were oxidized. Results regarding oxidation-initiated precipitation of oligomers are also reported.

Poly[dithio-2,5-(1,3,4-thiadiazole)] (PDMcT)–poly(3,4-ethylenedioxythiophene) (PEDOT) composite cathode for high-energy lithium/lithium-ion rechargeable batteries

“…Poly[dithio-2,5-(1,3,4-thiadiazole)] (PDMcT) was prepared by chemical polymerization of DMcT monomer following the procedure previously reported [22] …”

Lithium storage in conductive sulfur-containing polymers

“…Generally, the C-S stretching appears at ca. 800-600 cm À1 [25]. However, some reports have also assigned the peaks at 1080 and 670 cm À1 to the C-S stretching [26,27].…”

Sulfides organic polymer: Novel cathode active material for rechargeable lithium batteries

“…Later, varies organic disulfide compounds have been synthesized and studied, such as poly(1,4-phenylene-1,2,4-dithiazol-3 ,5 -yl) [3], cyclic disulfide polyamides [4], copolymer of 2,2-dithiodianiline and aniline [5], dimercaptan 2,5-dimercapto-1,3,4-thiadiazole (DMcT) [6], poly(bis(phenylamino)disulfide) [7], poly(4,6-dihydro-1H- [1,2]dithiino [4,5-c]pyrrole) [8], benzene-based polyorganodisulfide [9] and so on. We have reported the synthesis of anthracene based organic disulfide cathode active materials, anthra [1 ,9 ,8 -b,c,d,e] [4 ,10 ,5 -b ,c ,d ,e ] bis-[1,6,6a(6a-SIV)-trithia]pentalene (ABTH) and its homopolymer (PABTH) [10].…”