CCPR073 - Discovery of inorganic lithium solid electrolytes for all-solid-state batteries

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The development of solid electrolyte (SE) systems is a field that is ever-growing due to the increasing motivation to develop a commercially viable all-solid-state battery (ASSB). Currently, there are concerns with the limitations of Li-ion battery (LIB) technology, when compared with the higher hypothetical energy storage capacity of ASSBs. A focal point of ASSB development is the advancement of the state-of-the-art of solid electrolytes.Recently, a novel material was developed at the University of Liverpool, that utilised ion arrangements comparable to intermetallic systems to produce a system that has improved structural diversity and subsequently a high Li ion conductivity (Science, 2024, 383, 739-745). Such ion arrangements facilitate a wide array of cation coordination environments, providing low energy barriers and increased ionic conductivity when compared with other leading SE systems.The purpose of this research is to expand on this new structural chemistry by exploring new compositions and materials that may adopt this structure type. This involves diversification of cationic and anionic species. The hypothesis being that further increased disorder will improve the already impressive ionic conductivity of this system. Additionally, the relationship between known intermetallic structural motifs and ionic conductors will be explored further to identify other anion arrangements that are favourable as potential solid state Li ion conductors.In the pursuit to expand the capability of this novel system, the project will employ the use of computational techniques to derive hypothetically stable variations of this newly established system. Varied experimental approaches will be employed to seek to achieve computationally determined stable materials, with preliminary phase purity will be measured by Powder X-Ray Diffraction (PXRD) analysis and synchrotron data. Rietveld refinement will be used to characterise the structure of a novel material, possibly in combination with high-resolution single crystal XRD data.Elemental analysis will be thoroughly determined thereafter by inductively coupled plasma optical emission spectroscopy (ICP-OES), CHNS and NMR. Studies will then go on to quantify the performance of the material as a solid electrolyte, assessing the ionic conductivity by alternating current (AC) impedance measurements and electronic conductivity by direct current (DC) polarization. The Li-transport mechanism in newly developed materials will be understood by combining quantitative data and structural analysis with ab initio molecular dynamics (AIMD) to determine the Li transport mechanism and contribute overall to the understanding of the chemical space.