Review and evaluation of metal-hydride-based hydrogen sensors as safety devices for future sustainable aviation

Abstract

This paper presents an overview of metal-hydride-based hydrogen sensors and evaluates their potential for utilization in aerospace safety applications in future hydrogen-powered aviation. The ‘electrical resistance’, ‘cantilever expansion’, ‘nanogap expansion’, ‘fiber optical’, ‘chemochromic optical’ and ‘acoustic’ sensing principles are being described. Requirements including specific performance parameters for hydrogen sensors in aerospace safety applications are identified. Evaluation criteria are derived from these requirements and finally the sensing mechanisms are evaluated by means of a weighted point rating. The results of this evaluation reveal the high potential of ‘electrical resistance’, ‘cantilever expansion’, ‘nanogap expansion’ and ‘fiber optical’ sensors, although none of these principles meets all the requirements yet. With the transition to hydrogen-based aviation, metal hydrides and its various applications will become more attractive. Synergies between these technologies may further drive the research and development progress, so that metal-hydride-based hydrogen sensors can overcome their current drawbacks and contribute to the transition to future hydrogen-powered sustainable aviation.