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Title: Development Electrolytes for Next Generation All-Solid-State Li-ion batteries

Abstract: The lithium-ion batteries demand is growing fast, as illustrated by the nearly 20-fold increase in electric vehicle sales in just 5 years. This growth is fueled by continuous improvement of the battery properties, which for the next generation batteries poses the challenges of improved safety (now a concern due to the flammable nature of the organic liquid electrolytes, especially in fast-charging applications) and increased energy density. In all-solid-state batteries, a solid-state-electrolyte replaces the liquid organic electrolyte, yielding improved safety, increased specific energy density, and increased specific power density. One of the main challenges for solid-state electrolyte is reaching room temperature Li-ion conductivity comparable to the one of liquid electrolytes (i.e. 1-10 mS/cm).

Complex hydrides, such as LiBH4, have demonstrated promising properties as solid electrolyte, including a high electrochemical stability, even against lithium metal. In our group we have been investigating these materials since 8 years, and in the past years I have specifically focused on different approaches to achieve sufficient room temperature Li+ conductivity, needed for batteries applications, in LiBH4, such as halide substitution, and oxide-LiBH4 nanocomposites. We focused on both the fundamental understanding of the Li-ion conduction mechanism and enhancement and on the application of the materials synthetized, i.e. implementation in a battery cell. In my lecture I will give the background of this research and focus on recent work1 on exploring a promising approach to enhance the Li-ion conductivity of LiBH4 at room temperature, namely the creation of highly conductive interfaces by mixing it with MgO, and its use as solid-state electrolyte in a battery cell.

(1) Gulino, V.; Brighi, M.; Murgia, F.; Ngene, P.; de Jongh, P.; Černý, R.; Baricco, M. Room-Temperature Solid-State Lithium-Ion Battery Using a LiBH4–MgO Composite Electrolyte. ACS Appl. Energy Mater. 2021, 4 (2), 1228–1236. .