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Quinones as redox mediators for the lithium-oxygen battery

Quinones as redox mediators for the lithium-oxygen battery
Quinones as redox mediators for the lithium-oxygen battery
Increasing demand for lighter and more powerful batteries has driven research beyond lithium-ion batteries. One system that has received significant attention is lithium-oxygen. This system exploits the reduction of oxygen to lithium peroxide, to provide a theoretical specific energy of 3500 Wh kg-1. One of the major problems facing the lithium-oxygen battery is the passivation of the air electrode caused by insoluble lithium oxides and lithium carbonate formed from unstable electrolytes. These products are not fully oxidized during the charge step and accumulate within the electrode, causing the capacity to fade with each cycle.

This work focuses on the use of quinones as solution based catalysts in non-aqueous electrolytes to facilitate the electron transfer of both the oxygen reduction reaction (ORR) and the oxygen evolution reaction (OER). The required overpotential for the ORR is shown to decrease by 400 mV and the discharge capacity increase by 100% by incorporating quinones into the electrolyte. Analysis of the carbon electrode by X-ray diffraction confirms lithium peroxide as the discharge product. Furthermore the evolution and consumption of oxygen during cycling has been demonstrated to require only two electrons per mole of oxygen using on-line mass spectrometry indicating that the dominant reaction is the formation of lithium peroxide.
University of Southampton
Richardson, William Andrew
d5c5d485-b8f5-489d-9596-443e178e03e5
Richardson, William Andrew
d5c5d485-b8f5-489d-9596-443e178e03e5
Garcia-Araez, Nuria
9358a0f9-309c-495e-b6bf-da985ad81c37

Richardson, William Andrew (2017) Quinones as redox mediators for the lithium-oxygen battery. University of Southampton, Doctoral Thesis, 190pp.

Record type: Thesis (Doctoral)

Abstract

Increasing demand for lighter and more powerful batteries has driven research beyond lithium-ion batteries. One system that has received significant attention is lithium-oxygen. This system exploits the reduction of oxygen to lithium peroxide, to provide a theoretical specific energy of 3500 Wh kg-1. One of the major problems facing the lithium-oxygen battery is the passivation of the air electrode caused by insoluble lithium oxides and lithium carbonate formed from unstable electrolytes. These products are not fully oxidized during the charge step and accumulate within the electrode, causing the capacity to fade with each cycle.

This work focuses on the use of quinones as solution based catalysts in non-aqueous electrolytes to facilitate the electron transfer of both the oxygen reduction reaction (ORR) and the oxygen evolution reaction (OER). The required overpotential for the ORR is shown to decrease by 400 mV and the discharge capacity increase by 100% by incorporating quinones into the electrolyte. Analysis of the carbon electrode by X-ray diffraction confirms lithium peroxide as the discharge product. Furthermore the evolution and consumption of oxygen during cycling has been demonstrated to require only two electrons per mole of oxygen using on-line mass spectrometry indicating that the dominant reaction is the formation of lithium peroxide.

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Published date: March 2017

Identifiers

Local EPrints ID: 413848
URI: http://eprints.soton.ac.uk/id/eprint/413848
PURE UUID: acd4a2e1-9d17-4373-b62b-aa05f5ae5ec8
ORCID for Nuria Garcia-Araez: ORCID iD orcid.org/0000-0001-9095-2379

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Date deposited: 07 Sep 2017 16:33
Last modified: 29 Jun 2020 04:01

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Contributors

Author: William Andrew Richardson
Thesis advisor: Nuria Garcia-Araez ORCID iD

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