A Comprehensive Review on Next Generation Unmanned Aerial Vehicles: Hydrogen Fuel Cell Technology

Conventional lithium-ion batteries used in unmanned aerial vehicles (UAVs) are constrained by modest specific energy, which restricts flight endurance to roughly 10–40 min for small platforms. Hydrogen fuel cell technology has therefore attracted growing interest from both the military and the civil aviation sectors. Proton exchange membrane fuel cells (PEMFCs) combined with compressed hydrogen storage offer substantially higher system-level specific energy and high electrochemical conversion efficiency, and are at present the most promising alternative propulsion source for extended-endurance missions. Type IV 700 bar vessels represent the qualified state of the art for platforms below 25 kg maximum take-off weight, whereas linerless Type V vessels remain a promising but pre-qualification option. Realising these architectures also depends on lightweight structural materials, in particular carbon-fibre-reinforced polymer composites and the structural adhesives used to join the metallic boss to the composite shell. This review examines the fundamentals of PEMFC technology, hydrogen storage systems, hybrid power system architectures, energy management strategies including dynamic modelling and multi-stack power allocation, safety and certification requirements, representative field demonstrations, economic and environmental assessment, and the principal technical barriers and open research questions. Advanced thermal management, emerging electrode and membrane materials, health-aware and artificial-intelligence-assisted energy management, and a certifiable means of compliance for such controllers are identified as the factors that will determine whether hydrogen-powered UAV technology reaches commercial and operational maturity.