Origin of Electrochromism in High-Performing Nanocomposite Nickel Oxide

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• 作者：Feng Lin ; Dennis Nordlund ; Tsu-Chien Weng ; Dimosthenis Sokaras ; Kim M. Jones ; Rob B. Reed ; Dane T. Gillaspie ; Douglas G. J. Weir ; Rob G. Moore ; Anne C. Dillon ; Ryan M. Richards ; Chaiwat Engtrakul
• 刊名：ACS Applied Materials & Interfaces
• 出版年：2013
• 出版时间：May 8, 2013
• 年：2013
• 卷：5
• 期：9
• 页码：3643-3649
• 全文大小：377K
• 年卷期：v.5,no.9(May 8, 2013)
• ISSN：1944-8252

文摘

Electrochromic effects of transition metal oxides provide a great platform for studying lithium intercalation chemistry in solids. Herein, we report on an electronically modified nanocomposite nickel oxide (i.e., Li_2.34NiZr_0.28O_x) that exhibits significantly improved electrochromic performance relative to the state-of-the-art inorganic electrochromic metal oxides in terms of charge/discharge kinetics, bleached-state transparency, and optical modulation. The knowledge obtained from O K-edge X-ray absorption spectroscopy (XAS) and X-ray photoelectron spectroscopy (XPS) suggests that the internally grown lithium peroxide (i.e., Li₂O₂) species plays a major role in facilitating charge transfer thus enabling optimal electrochromic performance. This understanding is relevant to recent theoretical studies concerning conductivity in Li₂O₂ for lithium鈥揳ir batteries (as cited in the main text). Furthermore, we elucidate the electrochromism in modified nickel oxide in lithium ion electrolyte with the aid of Ni K-edge XAS and Ni L-edge XAS studies. The electrochromism in the nickel oxide materials arises from the reversible formation of hole states on the NiO₆ units, which then impacts the Ni oxidation state through the Ni3d-O2p hybridization states. This study sheds light on the lithium intercalation chemistry for general energy storage and semiconductor applications.

Keywords:

electrochromism; multicomponent; nickel oxide; X-ray absorption spectroscopy; lithium intercalation