Empowering Urban Skies: Energy Storage Solutions with Batteries, Fuel Cells, and Supercapacitors for Advanced Air Mobility and Air Taxi Systems

The rapid growth of urbanization and increasing congestion in metropolitan areas have spurred the development of Advanced Air Mobility (AAM) systems, with electric and hybrid air taxis emerging as a promising solution for sustainable urban transport. Central to the viability of AAM is the selection and integration of suitable energy storage and conversion technologies, which directly impact safety, endurance, cost, and scalability. This paper provides a comprehensive review of the current state and future prospects of batteries, supercapacitors, and fuel cells in the context of AAM applications. Batteries, particularly lithium-ion chemistries, are currently the most mature technology, enabling near-term demonstrations and certification efforts. However, their limitations in energy density, charging time, and thermal management restrict endurance and necessitate innovations in solid-state and lithium–sulfur variants. Supercapacitors, though limited in energy capacity, offer unparalleled power density and rapid response, making them ideal for handling transient loads during take-off, landing, and regenerative braking. Fuel cells present a promising long-term solution, providing high specific energy and zero carbon emissions at the point of use. Yet, their adoption depends heavily on the establishment of scalable hydrogen production, storage, and refueling infrastructure. The review further highlights hybrid architectures that combine these technologies, such as battery–supercapacitor and battery–fuel cell systems, to exploit complementary advantages. Integration challenges, including thermal management, power electronics, and intelligent energy management systems, are analyzed alongside safety considerations and certification requirements. Case studies of ongoing demonstrators illustrate the diverse strategies being pursued globally. Finally, the paper identifies key challenges and future directions, emphasizing material innovations, infrastructure readiness, supportive policy frameworks, and a roadmap for next-generation AAM energy systems. The findings underscore that while battery-powered air taxis are poised for near-term deployment, the long-term sustainability of AAM will rely on hybrid solutions and breakthroughs in advanced materials and hydrogen technologies.