The most important scientific problems to solve for the future is how to efficiently convert and store clean energy. To realize all-solid-state devices and high-performance sodium batteries we need to obtain an improved understanding and control of ion diffusion on the atomic scale. In this proposal we aim to study a novel enhancement of ion diffusion rate in a Na-battery material by the use of external pressure. Initial studies reveal a strong effect on the onset temperature for Na-ion diffusion with pressure. We have from neutron diffraction directly linked the onset of diffusion to a subtle structural phase transition. We estimate that with 3% lattice strains it is possible to improve the diffusion rate in the present compound with several orders of magnitude, which opens the door for improvements in device performance as well as the re-evaluation of previously discarded materials.