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E-Thesis 238 views

Towards Cost Effective and Sustainable Renewable Energy Storage Batteries / AMIR JALALIAN-KHAKSHOUR

Swansea University Author: AMIR JALALIAN-KHAKSHOUR

  • E-Thesis under embargo until: 26th May 2028

DOI (Published version): 10.23889/SUthesis.63622

Abstract

There is an urgent need to switch to a low-carbon economy, mostly using renewable energy generation sources, such as wind energy. Due to the intermittent generation nature of these generation methods, there is a need for an energy storage device to level any potential mismatch in generation/demand....

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Published: Swansea, Wales, UK 2023
Institution: Swansea University
Degree level: Doctoral
Degree name: EngD
Supervisor: Croft, Nick. and Margadonna, Serena.
URI: https://cronfa.swan.ac.uk/Record/cronfa63622
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Abstract: There is an urgent need to switch to a low-carbon economy, mostly using renewable energy generation sources, such as wind energy. Due to the intermittent generation nature of these generation methods, there is a need for an energy storage device to level any potential mismatch in generation/demand. The overall areas of interest in this thesis were, firstly what method or approach could be used to compare different electrochemical cell options for a wind-diesel, off grid generation system. Secondly, what are the future challenges with electrochemical cells and what knowledge creation could be carried out to help with this. The first goal of this work was considering the criteria of the selection of a suitable energy storage device. As per the industrial focused requirements of the Engineering Doctorate (EngD), a ‘business case’ using a commercial renewable energy system software (HOMER) was carried out to compare and contrast different commercial electrochemical cells, in the context of the sponsors wind turbine. It was found that the available commercial Lithium-ion cells were advantageous in terms of the levelised cost of energy output, due to superior performance characteristics. Sodium Ion Batteries (SIB’s) offer a potential cheaper, safer and more sustainable alternative to the current dominate technology in the energy storage market, the lithium-Ion batteries (LIB’s). Furthermore, the development of all solid-state batteries, in which the currently utilised liquid electrolytes are substituted for solid electrolyte materials, could lead to safer battery systems. Designing suitable solid electrolytes remains a huge scientific challenge, to achieve the desirable electrochemical stability, ion conduction and negligible electronic conduction. The sodium ion conducting Na3Zr2Si2PO12 solid electrolyte, is a promising solid electrolyte material, and is a prolifically studied material in scientific journal publications. A facile solid-state synthesis method was selected, with a novel concept of utilising nano-scale precursor particles to achieve high density, high purity, high conductivity Na3Zr2Si2PO12 pellets. The investigation was carried out with a direct comparison of nano-scale precursors to macro-scale precursors to have a direct comparison of the effect this has on material microstructure and electrochemical performance. The analysis included the use of scanning electron microscope (SEM) images, Brunauer-Emmett-Teller (BET) surface area and porosity measurements, to measure the material characteristics of the pre-sintered powders. For analysis of the synthesised Na3Zr2Si2PO12 pellets, X-ray diffraction (XRD) profiles and Rietveld refinement was used to characterise the phase formation composition and impurity species and content. SEM was used to characterise the crystal microstructure and grain/grain boundary details. Archimedes density testing was used to test the densification of the sintered pellets. To determine the ionic conductivity of the pellets electrochemical impedance spectroscopy (EIS) was used.To test the reliability of the developed sodium ion conducting electrolyte in an electrochemical cell, electrochemical studies were then carried out. Firstly, the interfacial resistances and efficacy to strip/plate sodium metal of the developed Na3Zr2Si2PO12 material was assessed. This was assessed by galvanostatically cycling a Na-metal/ Na3Zr2Si2PO12/Na-metal symmetrical cell. Then the interfacial resistance of the Na-metal/ Na3Zr2Si2PO12 interaction was assessed using an EIS measurement. The developed material pellets showed a promising performance, achieving a competitive ionic conductivity of 1.13 × 10-3 S.cm-1 for nano precursors using the highest sintering duration of 40 hours (at 1230°C). The next step was to develop a solid-state sodium ion cell, this was done with the use of a novel concept of using a reduced graphene oxide (rGO), organic cathode material in a solid-state cell. The use of a carbonaceous cathode material may provide advantages in terms of a ‘green’ material, when compared to traditional cathode materials. In the study a solid-state cell using a rGO cathode material, a sodium metal anode material and a Na3Zr2Si2PO12 solid electrolyte was developed. The performance of this cell was directly compared to an identical cell, except the use of a more conventional liquid electrolyte (1M NaClO4 in EC: PC). The solid state cell showed very promising results.
Item Description: A selection of third party content is redacted or is partially redacted from this thesis due to copyright restrictions.
Keywords: Sodium-Ion, Batteries, Solid electrolytes, renewable energy, sustainable
College: Faculty of Science and Engineering