Advanced materials processing and non-destructive evaluation for next-generation hydrogen storage systems: A review of protective coatings, membranes, and composite structures

The transition to a hydrogen-based economy critically depends on the development of safe, efficient, and durable storage systems. However, practical implementation of metal hydride beds and Type IV composite vessels faces three critical challenges: surface degradation and poisoning of storage media, the need for ultra-high purity hydrogen, and assurance of long-term structural integrity of composite overwraps. Addressing these interconnected issues demands a holistic approach integrating advanced materials processing with robust diagnostic tools. This review examines three synergistic technological pillars. First, we discuss protective coating technologies for powdered metal hydrides, including deposition devices and coating compositions that mitigate hydrogen embrittlement and impurity poisoning. Second, we review membrane filtration for hydrogen purification, analyzing prototype filter performance and integration as upstream components ensuring feed gas quality. Third, we explore non-destructive evaluation (NDT) methods for composite structures, focusing on conceptual prototype systems for in-situ structural health monitoring. By synthesizing advances across these fields, this review identifies current research trends, highlights critical knowledge gaps, and proposes a roadmap for concurrent engineering of materials, processing techniques, and diagnostic systems. The overarching goal is a unified framework for designing next-generation hydrogen storage solutions that are both high-performing and intrinsically safe.