title: Phase-Controlled Electrochemical Activity of Epitaxial Mg-Spinel Thin Films.
abstract: We report an approach to control the reversible electrochemical activity (i.e., extraction/insertion) of Mg(2+) 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 Mg(2+) 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.
authors.forename: Zhenxing
authors.initials: Z
authors.lastname: Feng
authors.forename: Xiao
authors.initials: X
authors.lastname: Chen
authors.affiliation: Center for Nanophase Materials Science, Oak Ridge National Laboratory , Oak Ridge, Tennessee 37831, United States.
authors.forename: Liang
authors.initials: L
authors.lastname: Qiao
authors.forename: Albert L
authors.initials: AL
authors.lastname: Lipson
authors.forename: Timothy T
authors.initials: TT
authors.lastname: Fister
authors.forename: Li
authors.initials: L
authors.lastname: Zeng
authors.affiliation: Department of Chemistry, University of Illinois at Chicago , Chicago, Illinois 60607, United States.
authors.forename: Chunjoong
authors.initials: C
authors.lastname: Kim
authors.affiliation: Department of Chemistry, University of Illinois at Chicago , Chicago, Illinois 60607, United States.
authors.forename: Tanghong
authors.initials: T
authors.lastname: Yi
authors.forename: Niya
authors.initials: N
authors.lastname: Sa
authors.forename: Danielle L
authors.initials: DL
authors.lastname: Proffit
authors.forename: Anthony K
authors.initials: AK
authors.lastname: Burrell
authors.affiliation: Department of Chemistry, University of Illinois at Chicago , Chicago, Illinois 60607, United States.
authors.forename: Jordi
authors.initials: J
authors.lastname: Cabana
authors.forename: Brian J
authors.initials: BJ
authors.lastname: Ingram
authors.affiliation: Center for Nanophase Materials Science, Oak Ridge National Laboratory , Oak Ridge, Tennessee 37831, United States.
authors.forename: Michael D
authors.initials: MD
authors.lastname: Biegalski
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Bedzyk
authors.forename: Paul
authors.initials: P
authors.lastname: Fenter
keywords: Mg-spinel; epitaxial phase stabilization; multivalent insertion; phase-selective electrochemical activity; pulsed laser deposition