PRINTED AND TEMPLATED 3D MXENE STRUCTURES FOR ENERGY STORAGE APPLICATIONS
Citation:
Spurling, Dahnan, PRINTED AND TEMPLATED 3D MXENE STRUCTURES FOR ENERGY STORAGE APPLICATIONS, Trinity College Dublin, School of Chemistry, Chemistry, 2023Download Item:
Abstract:
Recently, MXenes have emerged as a promising family of materials for a variety of energy storage devices, with much of the work surrounding supercapacitors based on Ti3C2Tx. Nanosheets of this material combine a metallically conductive titanium carbide core and a surface functionalised by a range of polar and pseudocapacitive surface groups such as F, O and OH ? denoted Tx. This Thesis first covers the synthesis and characterisation of Ti3C2Tx MXene, along with a facile freeze-thaw method for enhancing the yield of delaminated flakes by 42 ? 6%. The high conductivity and capacitance of this material makes it ideal for supercapacitors, though real-world applications will need control of electrode structure, as excessively dense and/or thick electrodes compromise both rate performance and specific capacitance. Therefore, this thesis describes two methods to create hierarchically structured 3D Ti3C2Tx electrodes at distinct length scales and for distinct applications.
At smaller scales, such as internet of things (IoT) and portable electronics, microsupercapacitors may present a solution to the requirement for compact energy storage. Specifically, directly incorporating microsupercapacitors into the product through printing is very appealing. To address the ion transport and capacitance issues of more conventional, dense, 2D printed films, we show that aerosol jet printing (AJP) of aqueous Ti3C2Tx inks can be used to fabricate symmetric, interdigitated microsupercapacitors where the 3D structured microsupercapacitors exhibit up to 97% greater areal capacitance than mass equivalent planar microsupercapacitors, up to 138 mF/cm2 at 5 mV/s. Additionally, three-electrode measurements of high areal loading 3D electrodes resulted in exceptional values for areal and volumetric capacitance of 3.47 F cm-2 and 347 F cm-3 respectively at 5 mV s-1.
For larger, macroscopic electrodes, this Thesis presents a method to create hierarchical 3D networked Ti3C2Tx thin film ?aeromaterial? with tuneable nano- and microstructure. Using sacrificial templates of sintered ZnO tetrapods, and careful control of the coating process, highly porous MXene structures with tailored layer thickness are obtained. These structures may be compressed to a desired thickness, from 2 mm to 0.05 mm to tailor the microstructure. By balancing porosity and thickness, electrodes that combine a high areal loading of up to ~7.2 mg cm-2, high density of ~1440 mg cm-3, and high electrochemical performance of 240 F g-1 and 140 F cm-3 are demonstrated. Optimising the above properties, electrodes with a remarkable areal capacitance of ~1.4 F cm-2 are achieved, even at high rates of 200 mV s-1, outperforming other state of the art MXene based electrodes of comparable density and thickness by almost 200%. I hope that this concept will pave the way to transfer the exceptional properties of nanomaterial thin film electrodes to the macroscopic level, enabling the development of advanced, high-performance electrodes for practically relevant energy storage applications.
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Irish Research Council (IRC)
Intel
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https://tcdlocalportal.tcd.ie/pls/EnterApex/f?p=800:71:0::::P71_USERNAME:SPURLINDDescription:
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Author: Spurling, Dahnan
Sponsor:
Irish Research Council (IRC)Intel
Advisor:
Nicolosi, ValeriaPublisher:
Trinity College Dublin. School of Chemistry. Discipline of ChemistryType of material:
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