Lithium Sulfonate Functionalization of Carbon Cathodes as a Substitute for Lithium Nitrate in the Electrolyte of Lithium–Sulfur Batteries
Artikel i vetenskaplig tidskrift, 2020

A method for grafting lithium sulfonate (LiSO3) groups to carbon surfaces is developed and the resulting carbons are evaluated for their potential to reduce the lithium polysulfide (LiPS) shuttle in lithium–sulfur (Li–S) batteries, replacing the common electrolyte additive lithium nitrate (LiNO3). The LiSO3 groups are attached to the ordered mesoporous carbon (CMK3) surface via a three-step procedure to synthesize LiSO3-CMK3 by bromomethylation, sodium sulfite (Na2SO3) substitution, and cation exchange. As a comparison, ethylenediamine (EN)-substituted CMK3, EN-CMK3, is also synthesized and tested. When used as a cathode in Li–S batteries, the unfunctionalized CMK3 suffers from strong LiPS shuttling as evidenced by its low initial Coulombic efficiencies (ICEs, <10%) compared to its functionalized derivatives EN-CMK3 and LiSO3-CMK3 (ICEs >75%). Postcycling analysis reveals the benefits of cathode surface functionalization on the lithium anode via an attenuated LiPS shuttle. When monitored at open circuit, the functionalized cathodes maintain their cell voltages much better than the CMK3 control and concurrent electrochemical impedance spectroscopy reveals their higher total cell resistance, which provides evidence for a reduced LiPS shuttle in the vicinity of both electrodes. Overall, such surface groups show promise as cathode-immobilized “lithium nitrate mimics.”.

lithium polysulfide shuttle

Li–S batteries

lithium nitrate

surface functionalization

bromomethylation

Författare

Samuel Joseph Fretz

Chalmers, Kemi och kemiteknik, Tillämpad kemi, Teknisk ytkemi

Urbi Pal

Deakin University

Gaetan M.A. Girard

Deakin University

P. C. Howlett

Deakin University

Anders Palmqvist

Rektor

Advanced Functional Materials

1616-301X (ISSN)

Vol. In Press

Ämneskategorier

Materialkemi

Annan kemiteknik

Annan kemi

DOI

10.1002/adfm.202002485

Mer information

Senast uppdaterat

2020-08-13