Oxygen Vacancies and Ordering of d‐levels Control Voltage Suppression in Oxide Cathodes: the Case of Spinel LiNi0.5Mn1.5O4‐δ |
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| Authors: | Peter V Sushko Kevin M Rosso Ji‐Guang Zhang Jun Liu Maria L Sushko |
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| Affiliation: | 1. Department of Physics and Astronomy and London Centre for Nanotechnology, University College London, Gower Street, London, WC1E 6BT, UK;2. Pacific Northwest National Laboratory, Richland, WA 99352, USA |
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| Abstract: | This study presents a microscopic model for the correlation between the concentration of oxygen vacancies and voltage suppression in high voltage spinel cathodes for Li‐ion batteries. Using first principles simulations, it is shown that neutral oxygen vacancies in LiNi0.5Mn1.5O4‐δ promote substitutional Ni/Mn disorder and the formation of Ni‐rich and Ni‐poor regions. The former trap oxygen vacancies, while the latter trap electrons associated with these vacancies. This leads to the creation of deep and shallow Mn3+ states and affects the stability of the lattice Li ions. Together, these two factors result in a characteristic profile of the voltage dependence on Li content. This insight provides guidance for mitigating the voltage suppression in LiNi0.5Mn1.5O4 and other cathodes. |
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| Keywords: | structure– property relationships spinel transition metal oxides oxygen vacancies energy storage |
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