Li-PIEs · Lithium-Conductive Phase-Independent Electrolytes

I propose combining organic synthesis, theoretical modelling, and materials science to develop a fundamentally new type of lithium- conducting electrolyte. Electrolytes are a vital part of modern life – for example, they are key components of the lithium-ion batteries powering personal electronics and electric vehicles. The electrolyte acts as the medium to transfer charges between the electrodes and its properties and performance depends on the type of material used. Different requirements associated with different sizes and types of devices is driving the development of new electrolyte materials.Traditionally, these materials are classified as either solid- or fluid-phase electrolytes, and the mechanisms of charge transfer differ between the two phases. Recently, a new type of electrolyte has been developed by the host PI that can function as either a solid or liquid electrolyte without losses in performance – they are phase-independent electrolytes (McGonigal et al., Science, 2024, accepted). However, these materials transport anions, while most batteries require cation-conducting electrolytes (e.g., lithium ions). To harness the potential of this new class of electrolytes, this concept must be adapted to apply to cation-conducting electrolytes, and this requires the development of newmolecular designs, their synthesis and characterisation.I will use DFT to model the structure and assembly of cyclopentadienide anions to identify candidates that have suitably diffuse charge and flexible structures to act as phase-independent electrolytes. I will then synthesise the top candidates and characterise their phase transition temperatures, phase structures, and lithium-ion conductivities. The relationship between molecular structure and the material properties will be developed to allow for the rational design of phase independent electrolytes. This will generate new research directions for the development of high-performing organic electrolytes.