Predicting lithium iron oxysulfides for battery cathodes

DOI: 10.1021/acsaem.1c03094

Authors: Bonan Zhu (University College London; The Faraday Institution) , David O. Scanlon (University College London; Diamond Light Source; The Faraday Institution)
Co-authored by industrial partner: No

Type: Journal Paper
Journal: Acs Applied Energy Materials

State: Published (Approved)
Published: January 2022

Abstract: Cathode materials that have high specific energies and low manufacturing costs are vital for the scaling up of lithium-ion batteries (LIBs) as energy storage solutions. Fe-based intercalation cathodes are highly attractive because of the low cost and the abundance of raw materials. However, existing Fe-based materials, such as LiFePO4, suffer from low capacity due to the large size of the polyanions. Turning to mixed anion systems can be a promising strategy to achieve higher specific capacity. Recently, antiperovskite-structured oxysulfide Li2FeSO has been synthesized and reported to be electrochemically active. In this work, we perform an extensive computational search for iron-based oxysulfides using ab initio random structure searching (AIRSS). By performing an unbiased sampling of the Li–Fe–S–O chemical space, several oxysulfide phases have been discovered, which are predicted to be less than 50 meV/atom from the convex hull and potentially accessible for synthesis. Among the predicted phases, two anti-Ruddlesden–Popper-structured materials Li2Fe2S2O and Li4Fe3S3O2 have been found to be attractive as they have high theoretical capacities with calculated average voltages of 2.9 and 2.5 V, respectively, and their distances to hull are less than 5 meV/atom. By performing nudged-elastic band calculations, we show that the Li-ion transport in these materials takes place by hopping between the nearest neighboring sites with low activation barriers between 0.3 and 0.5 eV. The richness of materials yet to be synthesized in the Li–Fe–S–O phase field illustrates the great opportunity in these mixed anion systems for energy storage applications and beyond.

Journal Keywords: oxysulfides; battery cathodes; lithium-ion batteries; energy storage applications; crystal structure prediction

Diamond Keywords: Batteries; Lithium-ion

Subject Areas: Materials, Energy, Chemistry


Technical Areas:

Added On: 17/01/2022 09:00

Discipline Tags:

Energy Storage Energy Physical Chemistry Energy Materials Chemistry Materials Science Chemical Engineering Engineering & Technology

Technical Tags: