A class of polysulfide catholytes for lithium-sulfur batteries: energy density, cyclability, and voltage enhancement
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:
- DE-AR0000377
- OSTI ID:
- 1211275
- Journal Information:
- Physical Chemistry Chemical Physics. PCCP (Print), Vol. 17, Issue 3; ISSN 1463-9076
- Country of Publication:
- United States
- Language:
- English
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