Using Experiment and First-Principles to Assess Electrochemical Windows of Common Solid Electrolytes for Their Application in All Solid-State Lithium Batteries.

Abstract

During the last decades, lithium batteries have been developed to power a growing number of portable applications and to meet the needs of an increasingly mobile society. Their industrial and commercial application has always occurred in two successive steps of equal importance: the discovery of new electrode materials and/or electrolytes, followed by their extensive optimisation. A new generation of lithium batteries has been recently developed to meet high expectations in terms of safety, stability and capacity: All-Solid-State Lithium Batteries (ASSLB), where the conventional liquid electrolyte (LiPF6 + EC/DEC) is replaced by a safer and more stable ceramic, polymer or glass solid electrolyte (SE). ASSLB are partly developed with the prospect of using high potential materials as positive electrode and lithium metal as negative electrode. This is only possible through SE stated large electrochemical windows. Nevertheless, values for these electrochemical windows are very divergent in the literature published through the last decades. Recently, several studies have come to specifically decry the frequent overestimation of SE electrochemical stabilities 1,2. Establishing a robust procedure to determine SE real electrochemical windows has become detrimental. Our work is focused on developing a combined theoretical and experimental approach to better assess the electrochemical stability of widely used SE such as Li1.3Al0.3Ti1.7(PO4)3, Li1.5Al0.5Ti1.5(PO4)3 and LiLaTi2O6. In this presentation, we shed light on the importance of selecting the right experimental setup and explore the link between experimental and interpreted thermodynamic results.1) Y. Tian, T. Shi, W. Richards, J. Li, J. Kim, S-H. Bo, G. Ceder. Energy Environ. Sci., 2017, 10, 11502)Z. Zhang, Y. Shao, B. Lotsch, Y-S. Hu, H. Li, J. Janek, L. Nazar, C-W. Nan, J. Maier, M. Armand, L. Chen. Energy Environ. Sci. 2018,11, 1945-1976.