A class of polysulfide catholytes for lithium-sulfur batteries: energy density, cyclability, and voltage enhancement

Journal Article · Thu Jan 01 04:00:00 EST 2015 · Physical Chemistry Chemical Physics. PCCP (Print)

DOI:https://doi.org/10.1039/c4cp04895d· OSTI ID:1211275

Yu, XW; Manthiram, A

Liquid-phase polysulfide catholytes are attracting much attention in lithium-sulfur (Li-S) batteries as they provide a facile dispersion and homogeneous distribution of the sulfur active material in the conductive matrix. However, the organic solvents used in lithium-polysulfide (Li-PS) batteries play an important role and have an impact on the physico-chemical characteristics of polysulfides. For instance, significantly higher voltages (similar to 2.7 V) of the S/S-n(2-) (4 <= n <= 8) redox couple are observed in Li-PS batteries with dimethyl sulfoxide (DMSO) and N-methyl-2-pyrrolidone (NMP) solvents. Accordingly, high power Li-PS batteries are presented here with the catholyte prepared with NMP solvent and operated with the highly reversible sulfur/long-chain polysulfide redox couple. On the other hand, a remarkable cyclability enhancement of the Li-PS battery is observed with the long-chain, ether-based tetraglyme (TEGDME) solvent. The voltage enhancement and the cyclability enhancement of the Li-PS batteries are attributed to the solvation effect, viscosity, and volatility of the solvents. Finally, highly concentrated polysulfide catholytes are successfully synthesized, with which high energy density Li-PS batteries are demonstrated by employing a multi-walled carbon nanotube (MWCNT) fabric electrode.

• Sponsoring Organization: USDOE Advanced Research Projects Agency - Energy (ARPA-E)
• DOE Contract Number: AR0000377
• OSTI ID: 1211275
• Journal Information: Physical Chemistry Chemical Physics. PCCP (Print), Journal Name: Physical Chemistry Chemical Physics. PCCP (Print) Journal Issue: 3 Vol. 17; ISSN 1463-9076
• Country of Publication: United States
• Language: English