Zhang, Wei;
(2024)
Development and Investigation of NASICON-Type Cathode Materials for High-Power and Long-Lasting Sodium-Ion Batteries.
Doctoral thesis (Ph.D), UCL (University College London).
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Abstract
Sodium-ion batteries are promising in large-scale energy storage systems, communication base stations and electric vehicles, etc. It is important to develop cathode materials with high voltage and high capacity in order to increase energy density for real-world applications. High ionic conductivity, high redox potential, good air tolerance, low volume change, and ease of redox tunability make sodium superionic conductor (NASICON)-type NaxMM’(PO4)3 (M/M’ = Mn, V, Fe, Cr, etc.) cathodes very promising. The majority of NASICON cathodes, however, continue to have poor capacities (< 120 mAh g-1 ) due to the restricted (one to two) electron transport per unit of chemical formula. The battery’s performance is further restricted by its low intrinsic electronic conductivity, poor capacity retention, and dissolution of transition metals. Strategies including electrode structure construction, interface optimisation, lattice regulation, entropy engineering, tuning the electronic structure, and phase control are adopted for these issues. This thesis consists of four chapters. In the first chapter, the introduction of the fundamentals of sodium-ion batteries is provided, including the background, mechanism, and literature reviews of recent progress on cathode materials. The second chapter describes a reduced graphene oxide supporting and Cr doping strategy to improve the typical NASICON-Na3V2(PO4)3 and activate its multi-electron reactions with excellent fast-charging performance. In the third chapter, a high-entropy strategy by five dopants (Cr, Mn, Fe, Al, and Mg) in transition metal sites of Na3V2(PO4)3 is adopted to further synergistically enhance the structural stability with good rate performances and prolonged lifespan. In the fourth chapter, an anionic coordination manipulation strategy is introduced to stabilise a more environmentally friendly, high-voltage, Mn-rich NASICON Na4MnCr(PO4)3 cathode material with improved electronic conductivity, reduced Mn dissolution, and an optimised Mn ligand framework. Besides, a series of theoretical studies and advanced in-situ & ex-situ characterisations are conducted to disclose the underlying mechanisms of all materials.
| Type: | Thesis (Doctoral) |
|---|---|
| Qualification: | Ph.D |
| Title: | Development and Investigation of NASICON-Type Cathode Materials for High-Power and Long-Lasting Sodium-Ion Batteries |
| Open access status: | An open access version is available from UCL Discovery |
| Language: | English |
| Additional information: | Copyright © The Author 2024. Original content in this thesis is licensed under the terms of the Creative Commons Attribution-NonCommercial 4.0 International (CC BY-NC 4.0) Licence (https://creativecommons.org/licenses/by-nc/4.0/). Any third-party copyright material present remains the property of its respective owner(s) and is licensed under its existing terms. Access may initially be restricted at the author’s request. |
| UCL classification: | UCL UCL > Provost and Vice Provost Offices > UCL BEAMS UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences > Dept of Chemistry |
| URI: | https://discovery.ucl.ac.uk/id/eprint/10189991 |
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