Exploring carbon electrode parameters in Li–O 2 cells: Li 2 O 2 and Li 2 CO 3 formation
Ensuring the stability of the electrode and electrolyte in Li–O 2 batteries and achieving a comprehensive understanding of parasitic side reaction management during cycling are key issues for the progress of this promising energy storage technology. Conditions that favour formation of either Li 2 O...
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Published in | Journal of materials chemistry. A, Materials for energy and sustainability Vol. 12; no. 12; pp. 7215 - 7226 |
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Main Authors | , , , , , , |
Format | Journal Article |
Language | English |
Published |
19.03.2024
|
Online Access | Get full text |
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Summary: | Ensuring the stability of the electrode and electrolyte in Li–O
2
batteries and achieving a comprehensive understanding of parasitic side reaction management during cycling are key issues for the progress of this promising energy storage technology. Conditions that favour formation of either Li
2
O
2
or Li
2
CO
3
in Li–O
2
cells on carbon-based electrodes were investigated.
Operando
Raman microscopy measurements and
ex situ
Raman and X-ray photoelectron spectroscopy (XPS) analyses were performed for Li–O
2
systems using Li[ClO
4
]/DMSO as the electrolyte and carbon paper (CP) and carbon paper with carbon nanotubes (CPCNT) as electrodes. Using CP electrodes (either treated or untreated with O
2
plasma), the major discharge product formed was Li
2
O
2
. In contrast, for CPCNT electrodes, the formation of Li
2
CO
3
as the main discharge product was observed at lower capacities, then significant formation of Li
2
O
2
proceeded at higher discharge capacities. XPS highlighted that the surface chemistry of the CPCNT electrode comprised fluorine and a variety of iron species, which could be linked to the promotion of Li
2
CO
3
formation. Furthermore, it was observed that when Li
2
CO
3
is the main discharge product, the active sites of functional groups on carbon surfaces that favour carbonate formation become coated/passivated. Consequently, the dominant reaction pathway then alters, leading to the growth of Li
2
O
2
over the surface. These outcomes emphasized the important role in cycling stability of the active sites on carbon electrodes, arising from the synthesis process or possible contaminants. |
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ISSN: | 2050-7488 2050-7496 |
DOI: | 10.1039/D3TA07701B |