Abstract
Anionic redox processes play a key role in determining the accessible capacity and cycle life of Li-rich cathode materials for batteries. We present a framework for investigating the anionic redox processes based on data readily available from standard DFT calculations. Our recipe includes a method of classifying different anionic species, counting the number of species present in the structure and a preconditioning scheme to promote anionic redox. The method is applied to a set of LixMnO3 (1 ≤ x ≤2) structures, with cationic disorder, to identify the evolution of anionic redox processes during cycling. Additionally, we investigate how different choices of exchange-correlation functionals affect the formation of anionic redox species. The preconditioning of the structures is shown to promote the formation of peroxo-like species. Furthermore, the choice of exchange-correlation functional has a large impact on the type of anionic redox species present, and thus care must be taken when considering localization in anionic species.
Highlights
Anionic redox processes are currently an intensely studied topic in battery research as it allows a significant increase in the accessible energy capacity in Li-rich cathodes in lithium-ion batteries[1,2]
We propose an algorithm for determining the types of anionic species present in the structures based on data readily accessible from standard density functional theory (DFT) calculations
The presented method is capable of estimating the amount of localized anionic redox and the trends in the evolution of anionic redox during cycling, all based on data readily available from standard DFT calculations
Summary
Anionic redox processes are currently an intensely studied topic in battery research as it allows a significant increase in the accessible energy capacity in Li-rich cathodes in lithium-ion batteries[1,2]. Li2MnO3 is one of the Li-rich cathode materials where the anionic redox is known to make a dominant contribution to its high theoretical capacity of around 460 mAh g−13–5. Many possible explanations for the cyclability were suggested, and anionic redox is regarded as one of the main contributors[5,9]. Li2MnO3 suffers from a fast capacity fading, in the initial cycling step[10]. Its fast capacity fading is attributed to the anionic redox process, which leads to an irreversible and potentially dangerous evolution of oxygen gas[7,10]
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
