Electrochemical characterisation of proposed counter electrode materials for electrochromic windows
Electrochemical characterisation of proposed counter electrode materials for electrochromic windows
Electrochromic windows are described as multilayer structures whose optical properties can be changed on the application of an electrical stimulus. They have assumed commercial importance due to their ability to modulate both the amount of visible light and IR radiation that may enter or leave a room. Therefore they may be utilised to help reduce lighting and heating costs. The history of elecrochromism is discussed along with the basic principles of device design and operation. The performance of the various materials that are used in a working device is also discussed. The role of the counter electrode, or ion storage layer, is shown to be just as critical in the implementation of a working electrochromic device as the working, or electrochromic layer. The principles of ion insertion are discussed with both the thermodynamic and kinetic viewpoints, thus illustrating the methodology required for the electrochemical characterisation of the materials. The vital role of the co - insertion of the electron is also discussed as it is this that directly affects the optical and electrical properties of the materials. The experimental techniques used to probe the materials under investigation are discussed.
Results are presented and analysed for two different proposed counter electrode materials, nickel oxide (NiO) and a mixture of vandadiumV oxide and titaniumIV oxide (vanadium/titanium oxide). The NiO is shown to have behaviour that changes considerably on cycling and to have little reversible capacity in a potential range which is acceptable. It is therefore rejected as a possible counterelectrode material. However, the vanadium/titanium oxide is shown to have a large reversible insertion capacity, > 20 mC cm-2 for all electrode thicknesses examined, within acceptable potential limits. The diffusion coefficient of the inserted Li+ ions is shown to be concentration dependent, and of the order � 1x10-13 cm2 s-1. Secondary Ion Mass spectrometry showed the inserted Li+ ions to be distributed evenly in the insertion layer. There was some evidence of parasitic reactions occurring during ion insertion and extraction.
University of Southampton
1997
Brotherston, Ian David
(1997)
Electrochemical characterisation of proposed counter electrode materials for electrochromic windows.
University of Southampton, Doctoral Thesis.
Record type:
Thesis
(Doctoral)
Abstract
Electrochromic windows are described as multilayer structures whose optical properties can be changed on the application of an electrical stimulus. They have assumed commercial importance due to their ability to modulate both the amount of visible light and IR radiation that may enter or leave a room. Therefore they may be utilised to help reduce lighting and heating costs. The history of elecrochromism is discussed along with the basic principles of device design and operation. The performance of the various materials that are used in a working device is also discussed. The role of the counter electrode, or ion storage layer, is shown to be just as critical in the implementation of a working electrochromic device as the working, or electrochromic layer. The principles of ion insertion are discussed with both the thermodynamic and kinetic viewpoints, thus illustrating the methodology required for the electrochemical characterisation of the materials. The vital role of the co - insertion of the electron is also discussed as it is this that directly affects the optical and electrical properties of the materials. The experimental techniques used to probe the materials under investigation are discussed.
Results are presented and analysed for two different proposed counter electrode materials, nickel oxide (NiO) and a mixture of vandadiumV oxide and titaniumIV oxide (vanadium/titanium oxide). The NiO is shown to have behaviour that changes considerably on cycling and to have little reversible capacity in a potential range which is acceptable. It is therefore rejected as a possible counterelectrode material. However, the vanadium/titanium oxide is shown to have a large reversible insertion capacity, > 20 mC cm-2 for all electrode thicknesses examined, within acceptable potential limits. The diffusion coefficient of the inserted Li+ ions is shown to be concentration dependent, and of the order � 1x10-13 cm2 s-1. Secondary Ion Mass spectrometry showed the inserted Li+ ions to be distributed evenly in the insertion layer. There was some evidence of parasitic reactions occurring during ion insertion and extraction.
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Published date: 1997
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Local EPrints ID: 460222
URI: http://eprints.soton.ac.uk/id/eprint/460222
PURE UUID: 54f68269-768a-4cd9-bd2a-29ea585a20e6
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Date deposited: 04 Jul 2022 18:13
Last modified: 04 Jul 2022 18:13
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Author:
Ian David Brotherston
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