New Materials for Solid-State Batteries

Rechargeable lithium-ion batteries are widely used in mobile applications. However, concerns about the availability of lithium and cobalt raw materials suggest alternative materials may be needed in future large-scale applications. This PhD project in solid-state materials chemistry will investigate alternative battery materials based on sodium. The materials to be targeted will be new families of mixed-metal sulphides. The high polarizability of the sulphide anion will aid diffusion of the sodium ions, on which the operation of the battery depends. The focus will be on relatively open framework structures containing large pore volumes. This will provide suitable sites for the incorporation of sodium ions during operation of the battery. The selection of materials to be investigated will be driven by the need to contain earth-abundant elements with a range of accessible oxidation states, to facilitate the redox processes that accompany the shuttling of sodium ions during the charge/discharge process. The project will combine materials synthesis by conventional high-temperature methods with novel mechanochemical and solvothermal approaches. Initial in-house characterization of the materials will exploit a combination of powder X-ray diffraction and electron microscopy. These investigations will be complemented by neutron diffraction and synchrotron X-ray diffraction measurements at the nearby ISIS and Diamond Facilities respectively. The energy storage performance of the materials will be evaluated through the construction of test cells for electrochemical studies.