(Best Student Presentation) Accurate First-Principle Study of High-Entropy Materials for Lithium-Ion Batteries

The availability of well performing and cost efficient energy storage devices is of utmost importance for a smooth transition to sustainable energy. Lithium-ion batteries (LIBs) have been successfully commercialized and widely used in various portable devices. Functional materials with higher voltages and greater capacity are needed to further boost the energy density of these batteries. Recently, high-entropy materials (HEMs), with their unique structural characteristics and tunable functional properties, are actively investigated by several research groups [1]. High-entropy alloys (HEAs) with superior mechanical properties were first reported about a decade ago. Afterwards, the concept was adapted to high-entropy ceramic (HECs), such as high-entropy oxides, which are promising materials for electrodes as well as electrolytes in LIBs [2-4]. These materials usually contain more than 5 metals in a single disordered phase [5]. HECs are constructed with different type of cations and anions. Their structural and electronic complexity represent a challenge to the computational methods. We discuss the refined Density Functional Theory (DFT)-based methods that are able to successfully describe the electronic structure of these materials. The correct assignment of oxidation states of transition metals is one of the challenges, and we will show importance of correct description of d orbitals for achieving this task. Besides, we will also discuss the cycling performance, as well as thermodynamic aspects of selected HECs [6,7]. Last but not least, we will briefly discuss how accurate atomistic simulations could accelerate design of high-performance materials for Li-ion batteries of the future. [1] Zhang, R.-Z. & Reece, M. J. Review of high entropy ceramics: design, synthesis, structure and properties. J. Mater. Chem. A 7 , 22148–22162 (2019). [2] Lun, Z. et al. Cation-disordered rocksalt-type high-entropy cathodes for Li-ion batteries. Nat. Mater. 20 , 214–221 (2021). [3] Sarkar, A. et al. High entropy oxides for reversible energy storage. Nat Commun 9 , 3400 (2018). [4] Jung, S.-K. et al. Unlocking the hidden chemical space in cubic-phase garnet solid electrolyte for efficient quasi-all-solid-state lithium batteries. Nat Commun 13 , 7638 (2022). [5] Rost, C. M. et al. Entropy-stabilized oxides. Nat Commun 6 , 8485 (2015). [6] Cui, Y. et al. High entropy fluorides as conversion cathodes with tailorable electrochemical performance. Journal of Energy Chemistry 72, 342–