Understanding the Effect of Cation Disorder on the Voltage Profile of Lithium Transition-Metal Oxides [electronic resource].
- Washington, D.C. : United States. Dept. of Energy. Office of Basic Energy Sciences, 2016. and Oak Ridge, Tenn. : Distributed by the Office of Scientific and Technical Information, U.S. Dept. of Energy
- Physical Description:
- pages 5,373-5,383 : digital, PDF file
- Additional Creators:
- University of California, Berkeley, United States. Department of Energy. Office of Basic Energy Sciences, and United States. Department of Energy. Office of Scientific and Technical Information
- Restrictions on Access:
- Free-to-read Unrestricted online access
- Cation disorder is a phenomenon that is becoming increasingly important for the design of high-energy lithium transition metal oxide cathodes (LiMO<sub>2</sub>) for Li-ion batteries. Disordered Li-excess rocksalts have recently been shown to achieve high reversible capacity, while in operando cation disorder has been observed in a large class of ordered compounds. The voltage slope (dV/dx<sub>u</sub> )is a critical quantity for the design of cation-disordered rocksalts, as it controls the Li capacity accessible at voltages below the stability limit of the electrolyte (~4.5-4.7 V). In this study, we develop a lattice model based on first principles to understand and quantify the voltage slope of cation-disordered LiMO<sub>2</sub>. We show that cation disorder increases the voltage slope of Li transition metal oxides by creating a statistical distribution of transition metal environments around Li sites, as well as by allowing Li occupation of highvoltage tetrahedral sites. We further demonstrate that the voltage slope increase upon disorder is generally smaller for highvoltage transition metals than for low-voltage transition metals due to a more effective screening of Li-M interactions by oxygen electrons. Short-range order in practical disordered compounds is found to further mitigate the voltage slope increase upon disorder. In conclusion, our analysis shows that the additional high-voltage tetrahedral capacity induced by disorder is smaller in Liexcess compounds than in stoichiometric LiMO<sub>2</sub> compounds.
- Published through SciTech Connect., 07/13/2016., Chemistry of Materials 28 15 ISSN 0897-4756 AM, and Aziz Abdellahi; Alexander Urban; Stephen Dacek; Gerbrand Ceder.
- Funding Information:
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