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Using Mo0.5Nb0.5O2 Solid Solutions With Varying Degrees of Phase Separation to Understand and Enhance High-Rate Electrochemical Charge Storage in a Model Lithium-Ion Battery Oxide Anode.

紀錄類型:	書目-語言資料,手稿 : Monograph/item
正題名/作者:	Using Mo0.5Nb0.5O2 Solid Solutions With Varying Degrees of Phase Separation to Understand and Enhance High-Rate Electrochemical Charge Storage in a Model Lithium-Ion Battery Oxide Anode./
作者:	Chen, Ewing Yu-Wen.
面頁冊數:	1 online resource (46 pages)
附註:	Source: Masters Abstracts International, Volume: 85-12.
Contained By:	Masters Abstracts International85-12.
標題:	Chemical engineering. -
電子資源:	click for full text (PQDT)
ISBN:	9798382837246

Using Mo0.5Nb0.5O2 Solid Solutions With Varying Degrees of Phase Separation to Understand and Enhance High-Rate Electrochemical Charge Storage in a Model Lithium-Ion Battery Oxide Anode.
Chen, Ewing Yu-Wen.

Using Mo0.5Nb0.5O2 Solid Solutions With Varying Degrees of Phase Separation to Understand and Enhance High-Rate Electrochemical Charge Storage in a Model Lithium-Ion Battery Oxide Anode. - 1 online resource (46 pages)

Source: Masters Abstracts International, Volume: 85-12.

Thesis (M.S.)--University of California, Los Angeles, 2024.

Includes bibliographical references

Li-ion batteries are technologically vital for reducing reliance on fossil fuels through the electrification of transportation, particularly electric vehicles. However, many Li-ion battery materials are limited in their ability to fast-charge. Notably, first-order phase transformations during lithiation/delithiation in these materials can hinder charging speeds through slow propagation of phase fronts a limited Li-ion diffusion. In this work, we modify the tunnel-structure host material MoO2 via cation substitution to create Mo0.5Nb0.5O2 solid solutions with varying extents of cation mixing to induce partial phase transition suppression. We utilize operando synchrotron X-ray diffraction with electrochemical analyses to elucidate the effect of cation mixing within the solid solution on suppression of first-order insertion-induced phase transitions and their effect on electrochemical performance. We find that there are two limits to the phase behavior. Materials synthesized a high temperature are quite crystalline, but can show clustering of Mo and Nb oxide domains in Mo0.5Nb0.5O2, and these materials show distinct first-order phase transitions during cycling, lower capacity, poor rate performance, and decreased cycle life. The use of metal-oxide cluster precursors in the synthesis produces a similar result. In poorly crystalline Mo0.5Nb0.5O2, the Mo and Nb remain well mixed, and the structure evolution becomes entirely single-phase/solid-solution, indicating first-order phase transition suppression. Unfortunately, the rate performance and capacity remain poor due to inhibited Li mobility in the disordered structures. Synthesizing materials at the lowest temperature that produces crystalline Mo0.5Nb0.5O2, results in materials with partial first-order phase transition suppression, and these materials demonstrated the best capacity, rate capability, and cycle life performance. Thus, this work demonstrates cation substitution as a method to control first-order phase transition behavior in tunnel structure Li insertion host materials for battery applications.

Electronic reproduction.
Ann Arbor, Mich. :
ProQuest,
2024

Mode of access: World Wide Web

ISBN: 9798382837246Subjects--Topical Terms:

555952
Chemical engineering.
Subjects--Index Terms:

Li-ion batteriesIndex Terms--Genre/Form:

554714
Electronic books.

Using Mo0.5Nb0.5O2 Solid Solutions With Varying Degrees of Phase Separation to Understand and Enhance High-Rate Electrochemical Charge Storage in a Model Lithium-Ion Battery Oxide Anode.
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520 $a Li-ion batteries are technologically vital for reducing reliance on fossil fuels through the electrification of transportation, particularly electric vehicles. However, many Li-ion battery materials are limited in their ability to fast-charge. Notably, first-order phase transformations during lithiation/delithiation in these materials can hinder charging speeds through slow propagation of phase fronts a limited Li-ion diffusion. In this work, we modify the tunnel-structure host material MoO2 via cation substitution to create Mo0.5Nb0.5O2 solid solutions with varying extents of cation mixing to induce partial phase transition suppression. We utilize operando synchrotron X-ray diffraction with electrochemical analyses to elucidate the effect of cation mixing within the solid solution on suppression of first-order insertion-induced phase transitions and their effect on electrochemical performance. We find that there are two limits to the phase behavior. Materials synthesized a high temperature are quite crystalline, but can show clustering of Mo and Nb oxide domains in Mo0.5Nb0.5O2, and these materials show distinct first-order phase transitions during cycling, lower capacity, poor rate performance, and decreased cycle life. The use of metal-oxide cluster precursors in the synthesis produces a similar result. In poorly crystalline Mo0.5Nb0.5O2, the Mo and Nb remain well mixed, and the structure evolution becomes entirely single-phase/solid-solution, indicating first-order phase transition suppression. Unfortunately, the rate performance and capacity remain poor due to inhibited Li mobility in the disordered structures. Synthesizing materials at the lowest temperature that produces crystalline Mo0.5Nb0.5O2, results in materials with partial first-order phase transition suppression, and these materials demonstrated the best capacity, rate capability, and cycle life performance. Thus, this work demonstrates cation substitution as a method to control first-order phase transition behavior in tunnel structure Li insertion host materials for battery applications.
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