摘要: Solid oxide fuel cells (SOFCs) represent a highly efficient electrochemical energy conversion technology; however, their commercial deployment is facing a series of bottlenecks, such as material degradation at high temperatures and limited kinetic at intermediate operating temperatures. It is, therefore, essential to have a comprehensive understanding of the atomicscale defect chemistry and ion transport mechanisms of materials caused by elements whose activity is difficult to detect with X-rays (such as oxygen and hydrogen). This review systematically summarizes key applications of neutron scattering techniques in addressing these fundamental challenges. These methods leverage the ultra-high sensitivity and excellent penetration depth of neutrons to light nuclei for in situ analysis, providing invaluable insights. We summarize key advances in neutron powder diffraction (NPD), which enables precise quantification of oxygen non-stoichiometry, resolution of complex crystal structures, and determination of the localization of proton/deuterium species in protonic conductors. Furthermore, we discuss how advanced neutron data analysis can be used to visualize ion diffusion paths and characterize dynamic processes. This review also covers the application of neutron diffraction in the nondestructively testing of residual strains and stresses, which is critical for mechanical durability. This work demonstrates how neutron scattering establishes a quantitative structure-property relationships linking atomic-scale phenomena to the performance of macroscopic SOFC, providing essential guidance for the design of next-generation materials.