Berlin 2018 – wissenschaftliches Programm

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MM: Fachverband Metall- und Materialphysik

MM 10: Battery Materials

MM 10.4: Vortrag

Montag, 12. März 2018, 16:30–16:45, H 0106

Understanding Cation-Disordered Cathode Materials — •Alexander Urban — University of St Andrews, Scotland, UK — University of California, Berkeley, USA

Cation-disordered transition-metal (TM) oxides have recently emerged as a new class of high-energy-density cathode materials for Li-ion batteries [1]. We previously showed that the practical capacity of disordered cathodes can be well estimated using percolation theory [2] and that high-throughput (HT) first principles calculations can be used to screen for novel materials in well-defined composition spaces [3]. However, apart from HT calculations, the discovery of novel disordered materials has mostly been guided by intuition.

Here, we combine a normal-mode analysis of TM site distortions with a tight-binding model and density-functional theory calculations to identify a specific electronic-structure mechanism that affects cation disorder in TM oxides. We show that d⁰ TM species (Ti⁴⁺, Nb⁵⁺, Mo⁶⁺, etc.) promote disordering, whereas TMs with other d-band fillings, especially d⁶ TMs (e.g., Co³⁺), destabilize the disordered phase [4]. This mechanism explains the stability of the known disordered cathodes and provides a simple guideline for the design of novel disordered compositions.

[1] Lee, Urban, Li, Su, Hautier, Ceder, Science 343 (2014) 519–522. [2] Urban, Lee, Ceder, Adv. Energy Mater. 4 (2014) 1400478. [3] Urban, Matts, Abdellahi, Ceder, Adv. Energy Mater. 6 (2016) 1600488. [4] Urban, Abdellahi, Dacek, Artrith, Ceder, Phys. Rev. Lett. 119 (2017) 176402.