Facile Electrochemical Mg-Ion Transport in a Defect-Free Spinel Oxide
- Argonne National Lab. (ANL), Lemont, IL (United States)
- Univ. of Illinois, Chicago, IL (United States)
- Argonne National Lab. (ANL), Lemont, IL (United States); Univ. of Illinois, Chicago, IL (United States)
Inversion, i.e. Mg/Mn antisite disorder, in a spinel oxide simultaneously causes blockage of favorable Mg2+ migration paths, raising activation barriers for diffusion, and it reduces the number of redox-active metals, limiting the maximum capacity in the spinel. Here, an inversion-free spinel, MgCr1.5Mn0.5O4, was synthesized by exploiting the different intrinsic crystal field stabilization of redox-active Cr and Mn in the form of a solid-solution. The capability of the tailored spinel to reversibly (de)intercalate Mg2+ at high redox potentials was investigated. The decrease in inversion dramatically lowered the electrochemical overpotential and hysteresis, and enabled utilization of high potentials at ~2.9 V (vs. Mg/Mg2+) upon re-intercalation of Mg2+. A combination of characterization techniques reveals that the structural, compositional, and redox changes within the spinel oxide were consistent with the observed electrochemical Mg2+ activity. Quantification of selective solely to lattice Mg2+ upon the electrochemical reaction was investigated by monitoring NMR signals in isotope 25Mg-enriched spinel oxides. Our findings enhance the understanding of Mg2+ transport within spinel oxide frameworks and provide conclusive evidence for bulk Mg migration in oxide lattices at high redox potentials with minimized electrochemical hysteresis.
- Research Organization:
- Argonne National Laboratory (ANL), Argonne, IL (United States)
- Sponsoring Organization:
- USDOE Office of Science (SC), Basic Energy Sciences (BES). Joint Center for Energy Storage Research (JCESR); National Science Foundation (NSF); Brookhaven National Laboratory (BNL)
- Grant/Contract Number:
- AC02-06CH11357; SC0012704
- OSTI ID:
- 1879893
- Journal Information:
- Chemistry of Materials, Journal Name: Chemistry of Materials Journal Issue: 8 Vol. 34; ISSN 0897-4756
- Publisher:
- American Chemical Society (ACS)Copyright Statement
- Country of Publication:
- United States
- Language:
- English
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