My PhD project is titled “From atomistic to continuum models of interfaces in Li-ion batteries” and funded by The Faraday Institution . This involves the computational modelling of grain boundaries and interfaces in solid state electrolytes. Current methods of modelling the affect of grain boundaries in solid electrolytes are based on Poisson-Boltzmann theory, which only considers systems where the defect mole fraction of defects is in the dilute limit. Defects in solid electrolytes are usually outside of this limit. Therefore my project focuses specifically on developing new models that can progress current Poisson-Boltzmann theory by investigating the affect of defect interactions in solid electrolytes. This will hopefully allow the appropriate modelling of solid state electrolytes and give indications on the true affect of grain boundaries in prospective solid state materials. These insights could help highlight optimal synthesis conditions in order to engineer the most preferable grain boundaries in these materials. Consequently, improving their performance and commercial viability.