Phase-Controlled Electrochemical Activity of Epitaxial Mg-Spinel Thin Films

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• 作者：Zhenxing Feng ; Xiao Chen ; Liang Qiao ; Albert L. Lipson ; Timothy T. Fister ; Li Zeng ; Chunjoong Kim ; Tanghong Yi ; Niya Sa ; Danielle L. Proffit ; Anthony K. Burrell ; Jordi Cabana ; Brian J. Ingram ; Michael D. Biegalski ; Michael J. Bedzyk ; Paul Fenter
• 刊名：ACS Applied Materials & Interfaces
• 出版年：2015
• 出版时间：December 30, 2015
• 年：2015
• 卷：7
• 期：51
• 页码：28438-28443
• 全文大小：417K
• ISSN：1944-8252

文摘

We report an approach to control the reversible electrochemical activity (i.e., extraction/insertion) of Mg²⁺ in a cathode host through the use of phase-pure epitaxially stabilized thin film structures. The epitaxially stabilized MgMn₂O₄ (MMO) thin films in the distinct tetragonal and cubic phases are shown to exhibit dramatically different properties (in a nonaqueous electrolyte, Mg(TFSI)₂ in propylene carbonate): tetragonal MMO shows negligible activity while the cubic MMO (normally found as polymorph at high temperature or high pressure) exhibits reversible Mg²⁺ activity with associated changes in film structure and Mn oxidation state. These results demonstrate a novel strategy for identifying the factors that control multivalent cation mobility in next-generation battery materials.