With increasing demands for high performance/capacity rechargeable batteries the materials science community is currently facing two severe issues. First of all there is from a safety point of view a strong drive towards all-solid-state energy devices where a new generation of energy materials needs to be developed. Secondly, the current lithium ion technology is being challenged due to the allocation of natural resources as well as a drastically increasing Li prizes. For the latter the sodium ion technology is put forward as a viable alternative. For this proposed experiment we aim to use the high intensity muon beam of the ISIS facility to investigate the microscopic diffusion mechanism in a series of Na-based materials that have showed promising tuning possibilities using both chemical substitution as well as nano-scale surface treatments.