Applications of Transition metal dichalcogenides and Transition metal dioxides for renewable technologies
Baker, E
Date: 15 April 2024
Thesis or dissertation
Publisher
University of Exeter
Degree Title
PhD in Physics
Abstract
In this thesis, we have studied many different two-dimensional materials for their use as either devices for photoelectrolysis or as Li-ion battery electrodes. Both of which are key technologies for the future of the human race and the planet as a whole. The first 3 chapters provide the background and methods used within this thesis. ...
In this thesis, we have studied many different two-dimensional materials for their use as either devices for photoelectrolysis or as Li-ion battery electrodes. Both of which are key technologies for the future of the human race and the planet as a whole. The first 3 chapters provide the background and methods used within this thesis. In chapter 4 we investigate MoS₂ and PdSe₂ for their potential use as photoelectrolysis devices, finding that their performances are unaffected by the presence of another material in a heterostructure, indicating that layered materials can be selected for different properties and combined into a heterostructure that would benefit from all these properties. In chapter 5, ScS₂ is investigated for use as a Li-ion battery electrode and shows great potential as a Li-ion cathode. The upper and lower intercalation limits are investigated and it is found that this material possesses a remarkably large window of stability when compared to that of other TMDCs with a capacity of 182.99 mAhg−1, high average voltage of 3.977 V and has minimal volumetric expansion. In chapter 6, nine different TMDC-graphene superlattices are investigated for their use as Li-ion intercalation electrodes. We find that ScS₂-graphene in both T- and R- phases possess voltages nearing 3 V, while the other seven lie in the range of 0 V to 1.5 V. Most of these show little volumetric expansion in the range of 5% to 10%, comparable to that of NMC at 8%. We also assess the capacities of these superlattices, finding that ScS₂-T, ScS₂-R and TiS₂-T possess large capacities of 306.77 mAh/g for both ScS₂ phases and 310.84 mAh/g respectively, with MoS₂-T possessing a capacity of 121.99 mAh/g. In chapter 7, we identify the region 0.666 ≤ 𝑥 ≤ 0.625, 0.222 ≤ 𝑦 ≤ 0.25 and 0.08333 ≤ 1 − 𝑥 − 𝑦 ≤ 0.125 in Ni𝑥Mn𝑦Co1−𝑥−𝑦O₂ as being the most likely within the NMC phase space to offer the highest capacities.
Doctoral Theses
Doctoral College
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