Direct ink writing of two-dimensional materials for electrochemical energy storage devices
File(s)
Author(s)
Panagiotopoulos, Apostolos
Type
Thesis
Abstract
Extrusion-based 3D printing offers a novel approach for creating intricate device geometries unachievable by other manufacturing techniques. This study introduces a method for fabricating miniaturised energy storage devices using robocasting and viscoelastic inks made from atomically thin transition metal dichalcogenide (TMD) sheets. The focus is on scaling up TMD-based ink processing for industrial viability to manufacture 3D electrodes with optimised architectures. This is achieved through a solid-state bulk-powder intercalation and direct hydration process, with a 100% material yield, unlike other exfoliation methods requiring sedimentation, filtration, and reincorporation into ink.
Extensive material characterisation was performed from bulk to exfoliated inks to 3D printed electrodes, including rheological assessment, surface and crystallographic analyses, imaging, tomographic microscopies, and novel electrochemical techniques were proposed. For the first time, a high-capacitive combination of mono to few-layered MoS2 and TiS2 were directly exfoliated and suspended in a hydrogel carrier. By adjusting the ink's rheological properties to enhance shear-induced extrusion flow, microelectrodes for symmetric supercapacitors were 3D printed. The rational design of 3D electrodes exposed highly capacitive 2D nanosheets, enabling rapid surface electrostatic charges and continuous charge transfer reactions, leading to higher capacitance and cyclability.
The optimised devices demonstrated state-of-the-art performance in non-carbonaceous TMD-only supercapacitors with a two-step ink processing, 3D printing of complex architectures, and remarkable performance metrics: 0.63F/cm² areal capacitance at 90 mg/cm², 6.5 F/g gravimetric capacitance, and 4.5 F/cm³ volumetric capacitance at 35 mg/cm². The 3D electrodes exhibited excellent cycling stability and coulombic efficiency over 100,000 cycles. This high performance is attributed to the metallic conductivity of lithiated TMDs and their crystallographic phase engineering.
Overall, this study presents a viable method for fabricating miniaturised energy storage devices using TMD-based inks and Direct Ink Writing technology, providing detailed characterisation and insights into the performance factors of TMD-based 3D printed supercapacitor electrodes.
Extensive material characterisation was performed from bulk to exfoliated inks to 3D printed electrodes, including rheological assessment, surface and crystallographic analyses, imaging, tomographic microscopies, and novel electrochemical techniques were proposed. For the first time, a high-capacitive combination of mono to few-layered MoS2 and TiS2 were directly exfoliated and suspended in a hydrogel carrier. By adjusting the ink's rheological properties to enhance shear-induced extrusion flow, microelectrodes for symmetric supercapacitors were 3D printed. The rational design of 3D electrodes exposed highly capacitive 2D nanosheets, enabling rapid surface electrostatic charges and continuous charge transfer reactions, leading to higher capacitance and cyclability.
The optimised devices demonstrated state-of-the-art performance in non-carbonaceous TMD-only supercapacitors with a two-step ink processing, 3D printing of complex architectures, and remarkable performance metrics: 0.63F/cm² areal capacitance at 90 mg/cm², 6.5 F/g gravimetric capacitance, and 4.5 F/cm³ volumetric capacitance at 35 mg/cm². The 3D electrodes exhibited excellent cycling stability and coulombic efficiency over 100,000 cycles. This high performance is attributed to the metallic conductivity of lithiated TMDs and their crystallographic phase engineering.
Overall, this study presents a viable method for fabricating miniaturised energy storage devices using TMD-based inks and Direct Ink Writing technology, providing detailed characterisation and insights into the performance factors of TMD-based 3D printed supercapacitor electrodes.
Version
Open Access
Date Issued
2023-09-24
Date Awarded
01/08/2024
License URL
Advisor
Mattevi, Cecilia
Saiz, Eduardo
Sponsor
Engineering and Physical Sciences Research Council
European Research Council
Grant Number
EP/N509486/1
Grant Agreement No. 819069
Publisher Department
Materials
Publisher Institution
Imperial College London
Qualification Level
Doctoral
Qualification Name
Doctor of Philosophy (PhD)