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High-Valent Iron Redox in Intercalation Electrodes /

紀錄類型:	書目-電子資源 : Monograph/item
正題名/作者:	High-Valent Iron Redox in Intercalation Electrodes /Hari Ramachandran.
作者:	Ramachandran, Hari,
面頁冊數:	1 electronic resource (128 pages)
附註:	Source: Dissertations Abstracts International, Volume: 87-05, Section: B.
附註:	Advisors: Chueh, William Committee members: Devereaux, Thomas; Nanda, Jagjit.
Contained By:	Dissertations Abstracts International87-05B.
標題:	Oxidation.
電子資源:	http://pqdd.sinica.edu.tw/twdaoapp/servlet/advanced?query=32316488
ISBN:	9798265427854

High-Valent Iron Redox in Intercalation Electrodes /
Ramachandran, Hari,

High-Valent Iron Redox in Intercalation Electrodes /Hari Ramachandran. - 1 electronic resource (128 pages)

Source: Dissertations Abstracts International, Volume: 87-05, Section: B.

Iron is the most abundant transition metal in Earth's crust, and redox cycling between its well-known low-valent oxidation states of Fe(II) and Fe(III) drives crucial processes in nature. The Fe(II)/(III) redox couple charge compensates cycling of lithium iron phosphate, a positive electrode (cathode) for lithium-ion batteries. High-valent iron redox couples, involving formal oxidation higher than Fe(III), could deliver higher electrochemical potentials and energy densities. However, because of the instability of high-valent Fe electrodes, they have proven difficult to probe and exploit in intercalation systems.In this thesis, I report and characterize a formal Fe(III)/(V) redox couple, by studying the charge-compensation mechanism of Li4FeSbO6 (LFSO), a layered Fe(III) oxide. First, I showcase a new synthesis pathway for LFSO that enables electrochemical investigation. Using valence-sensitive core level spectroscopy, I show that the high-voltage plateau displayed by LFSO is charge-compensated by a unique Fe(III)/(V) redox couple. The Fe(V) species has a negative charge-transfer ground state, coming from hole density on ligand states. Finally, I investigate the stability of the Fe(III)/(V) redox couple in LFSO and contrast it with the instability and O-dimerization observed in other Fe-redox cathodes, and show that the crystallographic ordering in LFSO is crucial to stabilizing the highly covalent Fe(V) state. This work presents a pathway for developing batteries with high energy density using low-cost and Earth-abundant Fe.

English

ISBN: 9798265427854Subjects--Topical Terms:

188332
Oxidation.

High-Valent Iron Redox in Intercalation Electrodes /
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