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Dissertation
Study of Early Transition Metal Carbides for Energy Storage Applications
Doctor of Philosophy (Ph.D.), Drexel University
Mar 2016
DOI:
https://doi.org/10.17918/etd-6657
Abstract
An increase in energy and power density is needed to match the growing energy storage demands linked with the development of renewable energy production, and portable electronics. Several energy storage technologies exist including lithium-ion batteries, sodium-ion batteries, fuel cells and supercapacitors. These systems are mutually complementary. For example, supercapacitors can deliver high power densities whereas batteries can be used for high energy density applications. The first objective of this work was to investigate the electrochemical performances of a new family of 2-D materials called MXenes by cyclic voltammetry and galvanostatic charge-discharge measurements and to propose new solutions to tackle the energy storage concern. To achieve this goal, several directions have been explored. The first part of the research focused on Ti₃C₂-based MXenes behavior as electrode materials for supercapacitors in aqueous electrolytes. The charge storage mechanisms in basic and neutral aqueous electrolytes, investigated by X-ray diffraction, were demonstrated to be attributed to cations intercalation between Ti₃C₂ layers. X-ray photoelectron spectroscopy highlighted the contribution of oxygenated functional groups on surface redox reactions in sulfuric acid. High capacitances were achieved, up to 520 F/cm3 and 325 F/g. Then the electrochemical behaviors of MXenes in sodium-based organic electrolytes were explored. A new hybrid system of sodium-ion capacitor was proposed. It was demonstrated that V2C-based MXene electrodes were suitable to be used as positive electrodes with an operating potential from 1 V to 3.5 V vs. Na⁺/Na. Continuous intercalation and de-intercalation of sodium ions between the V2C layers during sodiation and desodiation were showed by X-ray diffraction. An asymmetric sodium-ion capacitor full cell was assembled using hard carbon as negative electrode and showed promising results, with a capacity of 50 mAh/g. The last part was focused on the study of MXene electrodes for supercapacitors in an organic electrolyte; 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide (EMITFSI) in acetonitrile. High volumetric capacitances, up to 245 F/cm3, were achieved by using carbon nanotubes as an additive to improve ion accessibility to Ti₃C₂ layers. The redox intercalation of large EMI+ cations between Ti₃C₂ layers at -0.4 V vs. Ag was observed by X-ray diffraction.
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Details
- Title
- Study of Early Transition Metal Carbides for Energy Storage Applications
- Creators
- Yohan Dall'Agnese - DU
- Contributors
- Yury Gogotsi (Advisor) - Drexel University (1970-)Patrice Simon (Advisor) - Drexel University (1970-)
- Awarding Institution
- Drexel University
- Degree Awarded
- Doctor of Philosophy (Ph.D.)
- Publisher
- Drexel University; Philadelphia, Pennsylvania
- Number of pages
- xvii, 158 pages
- Resource Type
- Dissertation
- Language
- English
- Academic Unit
- Materials (Science and) Engineering (Metallurgical Engineering) [Historical]; College of Engineering (1970-2026); Drexel University
- Other Identifier
- 6657; 991014632237904721