Battery materials are highly complex; solid-state lithium conducting electrolytes are often highly disordered and the structure of many promising cathode materials for future technologies are poorly understood. Understanding their chemistry can be challenging even considering the non-defective system, yet defect chemistry can play an important part in defining their properties. This project aims to use first principles techniques to model both the kinetics and thermodynamics of defects in current and next generation battery materials in order to gain greater insight into material properties.