Influence of dopant species and Li-content on the Li-diffusion characteristics of high-Ni LiNiO2 based cathodes for next generation lithium-ion batteries

While increasing the Ni content of well-established transition metal layered oxide cathode materials improves the energy density, thermal and cycling stability can be adversely affected. As society pushes towards better performing battery materials for automotive applications, understanding why these instabilities arise and how to mitigate them is essential for the eventual improvement of commercial battery performance. It has been established that highly controlled small quantities of dopants on select atomic sites can act to improve cycling stability and longevity. For example, Mg doped onto the Li site can act as a structural pillar which helps to maintain atomic rigidity as the material when it is highly delithiated, mitigating structural collapse. We have recently developed a suite of doped LNO materials to further understand how the full theoretical capacity of high Ni content cathodes can be realised. We propose to study three variations of a material previously characterised by our group (LiNiO2), namely Mg-doped LNO, dual doped Mg+W-doped LNO, and Li excess LNO. Muon spectroscopy will allow us to elucidate what effect the subtle structural alterations have on the fundamental Li+ diffusion characteristics of each material. Such information will be valuable to understanding how dopants can be used to improve the performance of next-generation battery materials.