Amine and amide functionalized mesoporous carbons: a strategy improving sulfide/host interactions in Li‐S batteries

Samuel J. Fretz, Marco Agostini, Piotr Jankowski, Patrik Johansson, Aleksandar Matic, Anders E. C. Palmqvist*

*Corresponding author for this work

Research output: Contribution to journalJournal articleResearchpeer-review

Abstract

Lithium‐sulfur (Li‐S) batteries are of great interest due to their potentially high energy density, but the low electronic conductivity of both the sulfur (S 8 ) cathode active material and the final discharge product lithium sulfide (Li 2 S) require the use of a conductive host. Usually made of relatively hydrophobic carbon, such hosts are typically ill‐suited to retain polar discharge products such as the intermediate lithium polysulfides (LiPs) and the final Li 2 S. Herein, we propose a route to increase the sulfur utilization by functionalizing the surface of ordered mesoporous carbon CMK3 with polar groups. These derivatized CMK3 materials are made using a simple two‐step procedure of bromomethylation and subsequent nucleophilic substitution with amine or amide nucleophiles. We demonstrate that, compared to the unfunctionalized control, these modified CMK3 surfaces have considerably larger binding energies with LiPs and Li 2 S, which are proposed to aid the electrochemical conversion between S 8 and Li 2 S by keeping the LiPs species in close proximity to the carbon surface during Li‐S battery cycling. As a result, the functionalized cathodes exhibit significantly improved specific capacities relative to their unmodified precursor.
Original languageEnglish
JournalBatteries and Supercaps
ISSN2566-6223
DOIs
Publication statusAccepted/In press - 2020

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